diagnostic trouble codes (dtc) - Aisin, Allison and 5R110W

th
AND 4000
PRODUCT
FAMILIES TROUBLESHOOTING
– CONTROLS
3000 AND3000
4000 PRODUCT
FAMILIES
TROUBLESHOOTING
MANUAL—ALLISON 4MANUAL
GENERATION
ALLISON 4TH GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
PREFACE
Welcome to the TS3989EN Troubleshooting Manual. We make every effort to keep our service information current
and accurate. Because of the time lag involved with writing and printing processes, the transmission TCM may
report a code that has not yet been added to this document. If you encounter a code that is not yet in this
publication, please call the Allison Transmission Technical Assistance Center at 1-800-252-5283.
Go to the Table of Contents
Copyright© 2005 General Motors Corp.
Troubleshooting
Manual
2005 DECEMBER
TS3989EN
Allison Transmission
VOCATIONAL MODELS
3000 VOCATIONAL MODELS
3000 HS
3000 RDS
3000 EVS
3000 MH
3000 PTS
3000 TRV
3200 SP
3200 TRV
3500 RDS
3500 EVS
B 300(P)(R)
B 400(P)(R)
T 200
T 300
3500 SP
3700 SP
4000 VOCATIONAL MODELS
4000 EVS
4000 HS
4000 MH
4000 RDS
4000 TRV
4500 EVS
4500 HS
4500 RDS
4500 SP
4500 TRV
4700 EVS
4700 RDS
4800 EVS
Allison Transmission, General Motors Corporation
P.O. Box 894 Indianapolis, Indiana 46206-0894
www.allisontransmission.com
Printed in USA
Copyright © 2005 General Motors Corp.
B 500
B 500P
B 500R
B 500PR
T 425
T 450
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
FOREWORD — How to Use This Manual
This manual provides troubleshooting information for the 3000 and 4000 Product Families Transmissions. Service
Manuals SM4013EN and SM4014EN, plus Parts Catalogs PC2150EN and PC2456EN may be used in conjunction
with this manual.
This manual includes:
•
•
•
•
Description of the 3000 and 4000 Product Families Allison 4TH Generation Electronic Control system.
Description of the electronic control system components.
Description of diagnostic codes, system responses to faults, and troubleshooting.
Wire, terminal, and connector repair information.
Specific instructions for using many of the available or required service tools and equipment are not included in
this manual. The service tool manufacturer will furnish instructions for using the tools or equipment.
Additional information may be published from time to time in Service Information Letters (SIL) and will be
included in future revisions of this and other manuals. Please use these SILs to obtain up-to-date information
concerning Allison Transmission products.
This publication is revised periodically to include improvements, new models, special tools, and procedures. A
revision is indicated by a new date on the title page and in the lower left corner of the rear cover. Check with your
Allison Transmission service outlet for the currently applicable publication. Additional copies of this publication
may be purchased from authorized Allison Transmission service outlets. Look in your telephone directory under
the heading of Transmissions — Truck, Tractor, etc.
Take time to review the Table of Contents and the manual. Reviewing the Table of Contents will aid you in quickly
locating information.
NOTE:
Allison Transmission is providing for service of wiring harnesses and wiring harness components as
follows:
• Repair parts for the internal wiring harness and for wiring harness components attached to the
shift selector will be available through the Allison Transmission Parts Distribution Center (PDC).
Use the P/N from your appropriate parts catalog or from Appendix E in this manual. Allison
Transmission (AT) is responsible for warranty on these parts.
• Repair parts for the external harnesses and external harness components must be obtained from
St. Clair Technologies Inc. (SCTI). SCTI provides parts to any Allison customer or OEM and is
responsible for warranty on these parts. SCTI recognizes AT, manufacturers, and SCTI part
numbers. SCTI provides a technical HELPLINE at 519-627-1673 (Wallaceburg). SCTI will have
parts catalogs available. The SCTI addresses and phone numbers for parts outlets are:
St. Clair Technologies, Inc.
920 Old Glass Road
Wallaceburg, Ontario, N8A 4L8
Phone: 519-627-1673
Fax: 519-627-4227
ii
St. Clair Technologies, Inc.
Calle Damanti S/N Col
Guadalupe—Guaymas
Sonora, Mexico 85440
Phone: 011-526-2222-43834
Fax: 011-526 2222-43553
Copyright © 2005 General Motors Corp.
3000/4000 PRODUCT FAMILIES 4TH GENERATION ELECTRONIC CONTROLS TROUBLESHOOTING MANUAL
IMPORTANT SAFETY NOTICE
IT IS YOUR RESPONSIBILITY to be completely familiar with the warnings and cautions
used in this manual. These warnings and cautions advise against using specific service
procedures that can result in personal injury, equipment damage, or cause the equipment to
become unsafe. These warnings and cautions are not exhaustive. Allison Transmission could
not possibly know, evaluate, or advise the service trade of all conceivable procedures by which
service might be performed or of the possible hazardous consequences of each procedure.
Consequently, Allison Transmission has not undertaken any such broad evaluation.
Accordingly, ANYONE WHO USES A SERVICE PROCEDURE OR TOOL WHICH IS NOT
RECOMMENDED BY ALLISON TRANSMISSION MUST first be thoroughly satisfied
that neither personal safety nor equipment safety will be jeopardized by the service
procedures used.
Also, be sure to review and observe WARNINGS, CAUTIONS, and NOTES provided by the
vehicle manufacturer and/or body builder before servicing the Allison transmission in that
vehicle.
Proper service and repair is important to the safe and reliable operation of the equipment.
The service procedures recommended by Allison Transmission and described in this manual
are effective methods for performing troubleshooting operations. Some procedures require
using specially designed tools. Use special tools when and in the manner recommended.
The WARNINGS, CAUTIONS, and NOTES in this manual apply only to the Allison
transmission and not to other vehicle systems which may interact with the transmission. Be
sure to review and observe any vehicle system information provided by the vehicle
manufacturer and/or body builder at all times the Allison transmission is being serviced.
WARNINGS, CAUTIONS, AND NOTES
Three types of headings are used in this manual to attract your attention:
WARNING!
Is used when an operating procedure, practice, etc., which, if not correctly followed,
could result in injury or loss of life.
CAUTION:
Is used when an operating procedure, practice, etc., which, if not strictly observed,
could result in damage to or destruction of equipment.
NOTE:
Is used when an operating procedure, practice, etc., is essential to highlight.
Copyright © 2005 General Motors Corp.
iii
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
TRADEMARKS USED IN THIS MANUAL
The following trademarks are the property of the companies indicated:
• Allison DOCTM is a trademark of General Motors Corporation.
• DEXRON® is a registered trademark of General Motors Corporation.
• LPS® Cleaner is a registered trademark of LPS Laboratories.
• Loctite® is a registered trademark of the Loctite Corporation.
• MagiKey® is a registered trademark of NEXIQ Technologies, Inc.
• Teflon® is a registered trademark of the DuPont Corporation.
• TranSyndTM is a trademark of Castrol Ltd.
SHIFT SELECTOR TERMS AND DISPLAY INDICATIONS
Shift selector terms and displays are represented in this manual as follows:
• Button Names — ↑, ↓, “display mode”, MODE, etc.
• Transmission Ranges — D (Drive), N (Neutral), R (Reverse), 1 (First), 2 (Second), etc.
• Displays — “o, L”; “o, K”, etc. (Display occurs one character at a time.)
iv
Copyright © 2005 General Motors Corp.
AND 4000
PRODUCT
FAMILIES TROUBLESHOOTING
–
3000 AND 3000
4000 PRODUCT
FAMILIES
TROUBLESHOOTING
MANUAL—ALLISON MANUAL
4th GENERATION
CONTROLS
ALLISON 4TH GENERATION CONTROLS
TABLE OF CONTENTS
Page
Foreword . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .ii
SAFETY INFORMATION
Important Safety Notice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii
Warnings, Cautions, and Notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii
Trademarks Used in This Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iv
Shift Selector Terms and Display Indications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iv
SECTION 1. GENERAL DESCRIPTION
1–1. TRANSMISSION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1–1
1–2. TRANSMISSION CONTROL MODULE (TCM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1–3
1–3. SHIFT SELECTOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1–4
A. Pushbutton Shift Selector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1–4
B. Lever Shift Selector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1–5
1–4. THROTTLE POSITION SENSOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1–5
1–5. SPEED SENSORS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1–6
1–6. CONTROL MODULE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1–7
1–7. WIRING HARNESSES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1–9
A. External Wiring Harness. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1–9
B. Internal Wiring Harness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1–11
1–8. VEHICLE INTERFACE MODULE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1–12
1–9. AUTODETECT FEATURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1–12
A. Retarder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1–13
B. Oil Level Sensor (OLS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1–13
C. Throttle Source . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1–13
D. Engine Coolant Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1–14
1–10. TRANSID (TID) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1–14
SECTION 2. DEFINITIONS AND ABBREVIATIONS
2–1. CHECK TRANS LIGHT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2–1
2–2. ALLISON TRANSMISSION DIAGNOSTIC TOOL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2–1
2–3. ABBREVIATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2–3
Copyright © 2005 General Motors Corp.
v
AND 4000
PRODUCT
FAMILIES TROUBLESHOOTING
–
3000 AND 3000
4000 PRODUCT
FAMILIES
TROUBLESHOOTING
MANUAL—ALLISON MANUAL
4th GENERATION
CONTROLS
ALLISON 4TH GENERATION CONTROLS
TABLE OF CONTENTS (Continued)
Page
SECTION 3. BASIC KNOWLEDGE
3–1. BASIC KNOWLEDGE REQUIRED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3–1
3–2. USING THE TROUBLESHOOTING MANUAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3–1
3–3. SYSTEM OVERVIEW. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3–2
3–4. IMPORTANT INFORMATION IN THE TROUBLESHOOTING PROCESS . . . . . . . . . . . . . . . . 3–2
3–5. BEGINNING THE TROUBLESHOOTING PROCESS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3–4
3–6. TCM DIAGNOSTIC PROCEDURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3–5
3–7. RESTTING OF TCM PARAMETERS TO SUPPORT ENGINE UPDATE . . . …………………3–6
3–8. RESETTING TCM AUTOSELECT. . . ………………………………………………………3–6
SECTION 4. WIRE CHECK PROCEDURES
4–1. TESTING FOR OPENS, SHORTS BETWEEN WIRES, AND SHORTS-TO-GROUND . . . . . . . 4–1
4–2. TESTING AT TRANSMISSION FEEDTHROUGH CONNECTOR FOR INTERNAL
HARNESS OPENS, SHORTS BETWEEN WIRES, AND SHORTS-TO-GROUND . . . . . . . . . . 4–3
SECTION 5. OIL LEVEL SENSOR
5–1. INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5–2. ELECTRONIC FLUID LEVEL READING (SHIFT SELECTOR) . . . . . . . . . . . . . . . . . . . . . . . .
A. Fluid Level Reading Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5–3. ELECTRONIC FLUID LEVEL CHECK (ALLISON DOC™ FOR PC–SERVICE TOOL) . . . . .
A. Fluid Level Reading Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5–1
5–3
5–3
5–5
5–5
SECTION 6. DIAGNOSTIC CODES
6–1. DIAGNOSTIC CODE MEMORY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6–1
6–2. CODE READING AND CODE CLEARING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6–2
6–3. DIAGNOSTIC CODE RESPONSE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6–3
6–4. SHIFT SELECTOR DISPLAYS RELATED TO ACTIVE CODES . . . . . . . . . . . . . . . . . . . . . . . . 6–4
6–5. DIAGNOSTIC CODE LIST AND DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6–4
6–6. DIAGNOSTIC CODE TROUBLESHOOTING. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6–14
A. Beginning the Troubleshooting Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6–14
B. Solenoid Locations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6–14
C. Diagnostic Code Schematics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6–14
SECTION 7. INPUT AND OUTPUT FUNCTIONS
7–1. INPUT FUNCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7–1
7–2. OUTPUT FUNCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7–3
SECTION 8.
vi
GENERAL TROUBLESHOOTING OF PERFORMANCE COMPLAINTS
Copyright © 2005 General Motors Corp.
AND 4000
PRODUCT
FAMILIES TROUBLESHOOTING
–
3000 AND 3000
4000 PRODUCT
FAMILIES
TROUBLESHOOTING
MANUAL—ALLISON MANUAL
4th GENERATION
CONTROLS
ALLISON 4TH GENERATION CONTROLS
TABLE OF CONTENTS (Continued)
Page
APPENDICES
A. IDENTIFICATION OF POTENTIAL CIRCUIT PROBLEMS . . . . . . . . . . . . . . . . . . . . . . . . . . . A–1
B. CHECKING CLUTCH AND RETARDER PRESSURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B–1
C. SOLENOID AND CLUTCH CHART . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C–1
D. WIRE/CONNECTOR CHART . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D–1
E. CONNECTOR PART NUMBERS, TERMINAL PART NUMBERS,
TOOL PART NUMBERS, AND REPAIR INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . E–1
F. THROTTLE POSITION SENSOR ADJUSTMENT. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .F–1
G. WELDING ON VEHICLE/VEHICLE INTERFACE MODULE . . . . . . . . . . . . . . . . . . . . . . . . . . G–1
H. HYDRAULIC SCHEMATICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . H–1
J. 3000 AND 4000 PRODUCT FAMILIES WIRING SCHEMATIC . . . . . . . . . . . . . . . . . . . . . . . . . . J–1
K. SOLENOID RESISTANCE CHARTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . K–1
L. EXTERNALLY-GENERATED ELECTRONIC INTERFERENCE . . . . . . . . . . . . . . . . . . . . . . . . L–1
M. DIAGNOSTIC TREE—3000 AND 4000 PRODUCT FAMILIES HYDRAULIC SYSTEM . . . . M–1
N. ALLISON DOC™ FOR PC–SERVICE TOOL. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . N–1
P. INPUT/OUTPUT FUNCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .P–1
Q. THERMISTOR TROUBLESHOOTING INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Q–1
R. SAE J1939 COMMUNICATION LINK. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . R–1
Copyright © 2005 General Motors Corp.
vii
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
SECTION 1—GENERAL DESCRIPTION
1–1.
TRANSMISSION
The Allison 4th Generation Controls feature closed-loop clutch control to provide superior shift quality over a
wide range of operating conditions. The 3000 and 4000 Product Families transmissions configurations can be
programmed to have up to six forward ranges, neutral, and one reverse range. The MD 3070, 3700 SP, HD 4070/
4076, 4700 RDS, 4700/4800 EVS, 4700/4800 SP have up to seven forward ranges and one reverse.
Figure 1–1 is a block diagram of the basic system inputs and outputs.
SHIFT SELECTOR
RANGE AND
MODE SWITCH
DISPLAY
OIL LEVEL SENSOR
SPEED SENSORS
THROTTLE POSITION SENSOR
TCM
RETARDER MODULATION
SOLENOIDS
DIAGNOSTIC PRESSURE SWITCH
VEHICLE/ENGINE
COMMUNICATION LINKS
TEMPERATURE SENSOR
(SUMP/RETARDER)
VIM
INPUTS
OUTPUTS
V09074.00.00
Figure 1–1. Transmission Control Module
Figure 1–2 shows Allison 4th Generation electronic control components.
Allison 4th Generation Controls consist of the following elements:
• Remote 12V or 12/24V Max Feature Sealed Transmission Control Module (TCM)
• Remote Pushbutton or Lever Shift Selector
• Optional Secondary Shift Selector
• Throttle Position Sensor (TPS) (or electronic engine throttle data or PWM signal)
• Engine, Turbine, and Output Speed Sensors
• Control Module (Electro-Hydraulic Valve Body)
• Wiring Harnesses
• Vehicle Interface Module (VIM)
• Autodetect Feature
• TransID Feature
• Optional Retarder Controls
• Optional Engine Coolant Temperature Input.
NOTE:
• All external harnesses are OEM supplied.
• The VIM is an OEM option.
Copyright © 2005 General Motors Corp.
1–1
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
GENERAL DESCRIPTION
TRANSMISSION
CONTROL
MODULE
(TCM)
ALLISON DOC™
FOR PC
J1939
CONNECTOR
DIAGNOSTIC
TOOL
CONNECTOR
VIW
CONNECTOR
(OPTIONAL)
DEUTSCH 9-PIN
DIAGNOSTIC TOOL
CONNECTOR
VIM
CONNECTOR
SCI (J1587)
CONNECTOR
(OPTIONAL)
COMPACT
PUSHBUTTON
SELECTOR
RETARDER ACCUMULATOR
CONNECTOR
RETARDER
MODULATION
REQUEST (RMR)
CONNECTOR
TRANSFER CASE CONNECTOR
(3000 PRODUCT FAMILY 7– SPEED)
SENSOR HARNESS
CONNECTOR (OPTIONAL)
REMOTE LEVER
SELECTOR
OUTPUT
SPEED SENSOR
CONNECTOR
SHIFT
SELECTOR
CONNECTOR
RETARDER TEMP.
SENSOR CONNECTOR
THROTTLE POSITION
SENSOR (TPS)
CONNECTOR
REMOTE
PUSHBUTTON
SELECTOR
O
D
E
THROTTLE
POSITION
SENSOR (TPS)
M
R
VEHICLE
INTERFACE
MODULE
(VIM)
N
TURBINE
SPEED SENSOR
CONNECTOR
(4000 PRODUCT
FAMILY)
ENGINE
SPEED
SENSOR
CONNECTOR
D
Bulkhead Connector (Optional)
RETARDER “PCS5”
SOLENOID
CONNECTOR
STRIP PUSHBUTTON
SHIFT SELECTORS
(EUROPEAN
OEM)
1
2
R
N
D
3
D
N
R
NOTE: Illustration is not to scale. Actual harness
configuration may differ from this illustration.
20-WAY
TRANSMISSION
FEEDTHROUGH
HARNESS
CONNECTOR
V09274.01.00
.
Figure 1–2. Typical Allison 4th Generation Control Components
1–2
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
GENERAL DESCRIPTION
1–2.
TRANSMISSION CONTROL MODULE (TCM)
The electronic control of the transmission is performed by a microcomputer. The microcomputer is an independent
controller and is referred to as a Transmission Control Module (TCM). TCMs are available in both 12V and 12/24V
configurations to match the configuration of the vehicle electrical system.
The TCM (Figure 1–3) contains the microcomputer which is the brain of the control system. The TCM receives
and processes information defining:
• Shift selector
• Throttle position
• Sump/retarder temperature
• Pressure switch state
• Engine speed
• Turbine speed
• Transmission output speed.
The TCM uses the information to:
• Control transmission solenoids
• Supply system status
• Provide diagnostic information.
Each TCM has a date code laser etched on the outer case of the TCM. This is the date when the TCM passed final
testing. This date is commonly used to denote the change configuration level of the TCM. It is normal for the TCM
date displayed electronically to be a few days prior to the date shown on the label.
V09005.00.00
Figure 1–3. Transmission Control Module (TCM)
Copyright © 2005 General Motors Corp.
1–3
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
GENERAL DESCRIPTION
1–3.
SHIFT SELECTOR
Pushbutton and lever shift selectors for the Allison 4th Generation Series are remote mounted from the TCM and
communicate to the TCM via the J1939 communications data link. All shift selectors except the strip-type
pushbutton have a dual digit vacuum fluorescent (VF) display and a mode indicator (LED). During normal
transmission operation, illumination of the LED indicator shows that a secondary or special operating condition
has been selected by pressing the MODE button. During diagnostic display mode, illumination of the LED
indicator shows that the displayed diagnostic code is active. Display brightness is regulated by the same vehicle
potentiometer that controls dash light display brightness. More information on both types of shift selectors is
continued below.
A.
Pushbutton Shift Selector (Figure 1–4)
There are three full-function pushbutton shift selectors and a strip pushbutton shift selector. Strip
pushbutton shift selectors are used primarily by non-North American OEMs. A full-function shift
selector has a MODE button and diagnostic display capability through the dual digit vacuum
fluorescent (VF) display. The strip pushbutton shift selector does not have a MODE button,
diagnostic capability, or adjustable illumination. The full-function pushbutton shift selector has
six (6) pushbuttons which are R (Reverse), N (Neutral), D (Drive), ↓ (Down), ↑ (Up), and MODE.
Manual forward range downshifts and upshifts are made by pressing the ↓ (Down) or ↑ (Up) arrow
buttons after selecting D (Drive). The N (Neutral) button has a raised lip to aid in finding it by touch.
The MODE button is pressed to select a secondary or special operating condition, such as
ECONOMY shift schedule. Diagnostic information is obtained by pressing the ↑ (Up) and ↓ (Down)
arrow buttons at the same time.
The strip pushbutton shift selector has either three or six range selection positions as shown in
Figure 1–4. When a strip pushbutton shift selector is used, diagnostic information must be obtained
by using the Allison DOC™ For PC–Service Tool, or a customer-furnished remote display.
DISPLAY
DISPLAY
MODE ID
MODE ID
MODE INDICATOR
(LED)
MODE
MODE INDICATOR
(LED)
6
1
COMMON
COMPACT
2
3
D N R
STRIP PUSHBUTTON
SHIFT SELECTORS
V07178.01.00
Figure 1–4. Typical Pushbutton Shift Selectors
1–4
1
MODE
BUTTON
MODE
BUTTON
CONTOURED BEZEL
D N R
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
GENERAL DESCRIPTION
B. Lever Shift Selector (Figure 1–5)
The lever shift selector can have as many as six forward range positions (seven for the 7-speed
models), as well as R (Reverse) and N (Neutral). There is a hold override button which must be
pressed and held in order to move between certain selector positions. The hold override button must
be pressed when shifting between R, N, and D. The hold override button is released when the desired
selector position is reached. The selector lever can be moved freely between D and the numbered
forward ranges without pressing the hold override button. The lever selector can be chosen with the
lever on the left side or on the right side and with the R (Reverse) position toward the front or toward
the rear of the selector. Diagnostic and oil level (if sensor is present) information is obtained from the
LED display by pressing the “display mode” button.
HOLD OVERRIDE BUTTON
HOLD OVERRIDE BUTTON
MODE INDICATOR
(LED)
1
2
3
4
5
D
N
R
MODE INDICATOR
(LED)
MODE BUTTON
6
1
6
1
DIGITAL DISPLAY
DISPLAY MODE/
DIAGNOSTIC BUTTON
SIX-SPEED, LEFT-HAND
LEVER SELECTOR
WITH REVERSE TO REAR
R
N
D
5
4
3
2
1
MODE BUTTON
6
1
MODE ID
DIGITAL DISPLAY
SIX-SPEED, RIGHT-HAND
LEVER SELECTOR
WITH REVERSE TO FRONT
DISPLAY MODE/
DIAGNOSTIC BUTTON
CONTOURED BEZEL
V07177.01.00
Figure 1–5. Typical Lever Shift Selector
1–4.
THROTTLE POSITION SENSOR (Figure 1–6)
The Throttle Position Sensor (TPS) can be mounted to the engine, chassis, or transmission. The TPS contains a pull
actuation cable and a potentiometer. One end of the cable is attached to the engine fuel lever and the other, inside a
protective housing, to the TPS potentiometer. Output voltage from the TPS is directed to the TCM through the
external harness. The voltage signal indicates the throttle position and, in combination with other input data,
determines shift timing.
A
B
C
THROTTLE POSITION SENSOR
V00628
Figure 1–6. Throttle Position Sensor (Without Mounting Brackets)
Copyright © 2005 General Motors Corp.
1–5
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
GENERAL DESCRIPTION
1–5.
SPEED SENSORS (Figure 1–7)
Three speed sensors—engine speed, turbine speed, and output speed—provide information to the TCM. The
engine speed signal is generated by ribs on the shell of the torque converter pump. The turbine speed signal is
generated by the rotating-clutch housing spline contours. The output speed signal is generated by a toothed
member attached to the output shaft (except for the 3000 Product Family 7-speed models, where the toothed
member is the transfer case idler gear). The speed ratios between the various speed sensors allow the TCM to
determine if the transmission is in the selected range. Speed sensor information is also used to control the timing of
clutch apply pressures, resulting in the smoothest shifts possible. Hydraulic problems are detected by comparing
the speed sensor information for the current range to that range’s speed sensor information stored in the TCM
memory.
FORMER (BEFORE JANUARY, 2006)
3000 AND 4000
PRODUCT FAMILIES
ENGINE
(EXTERNAL)
4000
PRODUCT FAMILY
TURBINE
(EXTERNAL)
3000
PRODUCT FAMILY
TURBINE
(INTERNAL)
3000
PRODUCT FAMILY
(EXCEPT 7-SPEED)
RETARDER OUTPUT
(EXTERNAL)
3000
PRODUCT FAMILY
7-SPEED OUTPUT
(INTERNAL)
3000 AND 4000
PRODUCT FAMILIES
OUTPUT (EXTERNAL),
4000 PRODUCT FAMILY
RETARDER
3000
PRODUCT FAMILY
7-SPEED OUTPUT
(INTERNAL)
3000 AND 4000
PRODUCT FAMILIES
OUTPUT (EXTERNAL),
4000 PRODUCT FAMILY
RETARDER
CURRENT (JANUARY, 2006)
3000/4000
PRODUCT FAMILIES
ENGINE
(EXTERNAL)
4000
PRODUCT FAMILY
TURBINE
(EXTERNAL)
3000
PRODUCT FAMILY
TURBINE
(INTERNAL)
3000
PRODUCT FAMILY
(EXCEPT 7-SPEED)
RETARDER OUTPUT
(EXTERNAL)
V09819.00.00
Figure 1–7. Speed Sensors
1–6
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
GENERAL DESCRIPTION
1–6.
CONTROL MODULE (Figure 1–8)
The Allison 4th Generation Series transmission control module contains a main body assembly and solenoid valve
body assembly, which are mounted to an aluminum channel plate. The TCM issues commands to various solenoids
in the two valve bodies to govern fluid flow to the clutches (including torque converter clutch). The solenoids
produce an output pressure that is proportional to current from the TCM. Hence, the solenoids are referred to as
pressure control solenoids (PCS).
6-SPEED
3000 PRODUCT FAMILY
CONTROL MODULE
6-SPEED
4000 PRODUCT FAMILY
CONTROL MODULE
7-SPEED
3000 PRODUCT FAMILY
CONTROL MODULE
7-SPEED
4000 PRODUCT FAMILY
CONTROL MODULE
V09276.00.00
Figure 1–8. Allison 4th Generation Control Modules
Copyright © 2005 General Motors Corp.
1–7
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
GENERAL DESCRIPTION
The main valve body assembly contains the following:
• Main pressure regulator valve
• Control main regulator valve
• Converter flow valve
• Lube regulator valve
• Converter regulator valve
• Exhaust backfill valve
• Two latching logic valves
• On/Off solenoid SS1.
The solenoid valve body assembly contains the following:
• Pressure control solenoid MAIN MOD
• PCS1 (A trim)
• PCS2 (B trim)
• PCS3 (C trim)
• PCS4 (D trim)
• TCC (lockup)
• Diagnostic pressure switch PS1
• Five solenoid regulator valves
• One diagnostic valve.
The low valve body assembly (in 3000 and 4000 Product Families 7-speed models) contains solenoid PCS6 (C6)
and one ON/OFF solenoid SS2 (C6 enable). Refer to the appropriate service manual for valve locations.
The Allison 4th Generation controls system includes a main modulation solenoid. Modulated main pressure results
in improved cooler flow and reduced pump losses when throttle position and output speed is low. The Allison 4th
Generation Controls TCM commands the main mod solenoid ON when all of the following conditions are
simultaneously met:
• Sump temperature is greater than 30ºC (86ºF) and less than 150ºC (302ºF) [greater than –5ºC (23ºF) and
•
•
•
•
•
less than 225ºC (437ºF) for 4700 and 4800 model transmissions].
Engine speed less than 1200 rpm in all ranges except neutral. There are no restrictions on engine speed
in neutral.
Throttle percentage less than 15 percent in reverse, low (7-speed), first, or second range. Main mod may
be commanded ON in neutral at any throttle position.
Output speed is less than 250 rpm in neutral, reverse, low (7-speed), first, or second range.
The PTO input to the TCM indicates the PTO is OFF.
Shift not in progress.
The TCM may activate the main mod solenoid for improved clutch control and transmission response during other
unusual operating situations.
A temperature sensor (thermistor) is located in the internal wiring harness. Changes in sump fluid temperature are
indicated by changes in sensor resistance, which changes the signal sent to the TCM. Refer to the chart in
Appendix Q.
The oil level sensor (OLS) is a float type device mounted on the control module channel plate. The OLS senses
transmission fluid level by electronically measuring the buoyancy forces on the float. The sensor operates on 5VDC
supplied by the TCM. The oil level sensor is available on any 3000 and 4000 Product Families transmissions except
the 3000 7-speed transmissions.
1–8
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
GENERAL DESCRIPTION
The diagnostic pressure switch PS1 is mounted on the solenoid valve body assembly and performs the following
two functions:
• When the C5 clutch is filled, PS1 senses PCS2 solenoid regulator valve position to verify proper C3
clutch control in reverse, neutral, and first range.
• When the C5 clutch is exhausted, as in second through sixth ranges, PS1 verifies the position of the C1
and C2 latch valves.
The turbine speed sensor is also mounted on the control module for the 3000 Product Family transmissions. The
turbine speed sensor is directed at the rotating-clutch housing. The turbine speed sensor on the 4000 Product
Family transmission is located on the outside of the main housing.
1–7.
WIRING HARNESSES
A.
External Wiring Harness (Figure 1–9)
The TCM uses a single 80-way connector, which is used to receive input from the following:
Transmission
Engine
Turbine
Output speed sensor
TPS
Vehicle interface module (VIM)
Retarder control module
Shift selector
Diagnostic tool connector
Retarder
Retarder temperature sensor
Accumulator
Many harnesses will include a bulkhead fitting to separate cab and chassis components. Also, many
different styles and materials for harnesses are likely to be encountered.
NOTE:
Allison Transmission is providing for service of wiring harnesses and wiring harness components as
follows:
• Repair parts for the internal wiring harness and for wiring harness components attached to the
shift selector will be available through the Allison Transmission Parts Distribution Center (PDC).
Use the P/N from your appropriate parts catalog or from Appendix E in this manual. Allison
Transmission is responsible for warranty on these parts.
• Repair parts for the external harnesses and external harness components must be obtained from
St. Clair Technologies Inc. (SCTI). SCTI provides parts to any Allison customer or OEM and is
responsible for warranty on these parts. SCTI recognizes Allison Transmission, manufacturers,
and SCTI part numbers. SCTI provides a technical HELPLINE at 519-627-1673 (Wallaceburg).
SCTI will have parts catalogs available. The SCTI addresses and phone numbers for parts
outlets are:
St. Clair Technologies, Inc.
920 Old Glass Road
Wallaceburg, Ontario, Canada N8A 4L8
Phone: 519-627-1673
Fax: 519-627-4227
St. Clair Technologies, Inc.
Calle Damanti S/N Col
Guadalupe—Guaymas
Sonora, Mexico 85440
Phone: 011-526 2222-43834
Fax: 011-526-2222-43553
• SCTI is the source for external harness repair parts.
Copyright © 2005 General Motors Corp.
1–9
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
GENERAL DESCRIPTION
TRANSMISSION
CONTROL
MODULE
(TCM)
ALLISON DOC™
FOR PC
J1939
CONNECTOR
DIAGNOSTIC
TOOL
CONNECTOR
VIW
CONNECTOR
(OPTIONAL)
DEUTSCH 9-PIN
DIAGNOSTIC TOOL
CONNECTOR
VIM
CONNECTOR
SCI (J1587)
CONNECTOR
(OPTIONAL)
COMPACT
PUSHBUTTON
SELECTOR
RETARDER ACCUMULATOR
CONNECTOR
RETARDER
MODULATION
REQUEST (RMR)
CONNECTOR
TRANSFER CASE CONNECTOR
(3000 PRODUCT FAMILY 7– SPEED)
SENSOR HARNESS
CONNECTOR (OPTIONAL)
REMOTE LEVER
SELECTOR
OUTPUT
SPEED SENSOR
CONNECTOR
SHIFT
SELECTOR
CONNECTOR
RETARDER TEMP.
SENSOR CONNECTOR
THROTTLE POSITION
SENSOR (TPS)
CONNECTOR
REMOTE
PUSHBUTTON
SELECTOR
O
D
E
THROTTLE
POSITION
SENSOR (TPS)
M
R
VEHICLE
INTERFACE
MODULE
(VIM)
N
TURBINE
SPEED SENSOR
CONNECTOR
(4000 PRODUCT
FAMILY)
ENGINE
SPEED
SENSOR
CONNECTOR
D
Bulkhead Connector (Optional)
RETARDER “PCS5”
SOLENOID
CONNECTOR
STRIP PUSHBUTTON
SHIFT SELECTORS
(EUROPEAN
OEM)
1
2
R
N
D
3
D
N
R
NOTE: Illustration is not to scale. Actual harness
configuration may differ from this illustration.
20-WAY
TRANSMISSION
FEEDTHROUGH
HARNESS
CONNECTOR
V09274.01.00
Figure 1–9. Typical 4th Generation Electronic Controls External Wiring Harnesses
1–10
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
GENERAL DESCRIPTION
B. Internal Wiring Harness (Figure 1–10)
The internal wiring harness provides connection between the following:
•
•
•
•
•
•
External harness
Pressure control and shift solenoids
Oil level sensor
Diagnostic pressure switch
Temperature sensor
Turbine speed sensor.
TCC (LOCKUP)
PCS1 (C1)
PCS2 (C2/C3)
PS1 DIAGNOSTIC
PRESSURE SWITCH
NT1 TURBINE
SPEED SENSOR
(3000 ONLY)
MAIN MOD
PCS6
(C6, 7-SPEED)
SS1
ON/OFF
OIL LEVEL SENSOR
(4000 ONLY)
PCS4 (C4)
OIL
TEMPERATURE
SENSOR
PCS3 (C3\C5)
SS2
(3000 AND 4000 PRODUCT
FAMILIES 7-SPEED C6 ENABLE)
OIL LEVEL SENSOR
(3000, EXCEPT 7-SPEED)
V09251.00.00
Figure 1–10. Allison 4th Generation Internal Wiring Harness
Copyright © 2005 General Motors Corp.
1–11
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
GENERAL DESCRIPTION
1–8.
VEHICLE INTERFACE MODULE (Figure 1–11)
The vehicle interface module (VIM) provides relays, fuses, and connection points for interface with the output side
of the vehicle electrical system. VIMs are available for both 12V and 24V electrical systems. The VIM for 12V
systems uses all 12V relays. The VIM for 24V systems has all 24V relays. Refer to the appropriate parts catalog for
the transmission assembly number that you are servicing for detailed parts information. Refer to Pages D–15 and
D–16 for VIM wire number and terminal information.
Some OEMs may provide their own equivalent for the VIM which performs the same functions as the VIM shown
in Figure 1–11.
V00631.02
Figure 1–11. Vehicle Interface Module (VIM)
1–9.
AUTODETECT FEATURE
Autodetect is active on the first 25 engine starts and, in the case of throttle source detection logic, may continue
past 25 ignition cycles until a valid source is determined (details follow in A through D below). Autodetect takes
place within the first 30 seconds of each engine start monitored. Autodetect searches for the presence of the
following transmission components or data inputs in the priority listed:
Retarder
Oil Lever Sensor (OLS)
Throttle
Engine Coolant Temperature
Present, Not Present
Present, Not Present
TPS, J1587, J1939
Sensor, J1939, J1587
Even after autodetect has been completed, it can be reset to monitor an additional group of engine starts. Reset may
be necessary if a device known to be present is not detected or if an autodetectable component or sensor was added
after the initial vehicle build. Reset is accomplished by using Allison DOC™ For PC–Service Tool. To use the
Allison DOC™ For PC–Service Tool, select “RESET AUTODETECT” to search for all four devices. Select
“RESET AUTODETECT RETARDER” to search for a retarder only. Selecting “RESET ADAPTIVE SHIFT
PARAMETERS” will not reset autodetect logic.
The Allison DOC™ For PC–Service Tool can also be used to override autodetect and manually enter the
component or sensor to be recognized by the TCM by changing appropriate “customer modifiable constants”
(CMC). The four items above are the only CMCs that are autodetectable. Other CMCs can be changed at any time
and are not related to autodetect. Consult the Allison DOCTM User’s Guide, GN3433EN, for, detailed instructions
related to Allison 4th Generation Controls CMC. Additional details for each of the four autodetectable features are
given below.
1–12
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
GENERAL DESCRIPTION
A.
Retarder
Autodetect searches for the presence of pressure control solenoid 5 (PCS5) to the retarder during the
first 35 engine ignition cycles. Retarder autodetect will countdown for a maximum of 35 ignition
cycles while recording detections of a retarder. A retarder will be identified as present and the retarder
autodetect logic will stop once it is detected for three consecutive ignition cycles. If the ignition cycle
counter completes the 35 cycles before there are three consecutive detections of a retarder, the
software will log that there is no retarder and the retarder autodetect logic will stop. If the autodetect
logic is not satisfied during the first 35 engine starts, the retarder is not detected and will not function
on subsequent engine starts.
WARNING:
If a retarder is present but is not detected by autodetect, the retarder will not
function. Be sure to check for proper functioning immediately after the 35th
engine start. If the retarder is not functioning, check PCS5 solenoid for an open,
short-to-ground, or short-to-battery condition. Use the Allison DOC™ For PC–
Service Tool to reset retarder autodetect or to manually select the presence of the
retarder after the PCS5 circuit is repaired.
B. Oil Level Sensor (OLS)
NOTE:
If an OLS is known to be present, but has not been detected, a possible cause is that the transmission
fluid level is too low. Check the fluid level before beginning the OLS troubleshooting.
Oil level sensor autodetect will countdown for a maximum of 25 engine starts while recording
detections of an OLS. The TCM monitors the OLS input voltage on wire 116. OLS input voltage
must exceed a predetermined level for the TCM to record a detection. Additionally, OLS detection
must occur within 12.5 seconds on any given engine start. An OLS will be identified as present and
the OLS autodetect logic will stop once it is detected during any single engine start.
If the engine start counter completes 25 cycles before TCM records one detection of an OLS, the
software will log that there is no OLS present and the OLS autodetect logic will stop. Then the TCM
concludes that no OLS is present.
No OLS diagnostics take place until the OLS is detected. Frequently check for the presence of oil
level diagnostics if the transmission is known to contain an OLS. If an OLS is known to be present,
but has not been detected, troubleshooting the OLS circuit is required. After the OLS circuit is
repaired, reset autodetect or manually select the OLS function using the Allison DOC™ For PC–
Service Tool.
C. Throttle Source
Throttle autodetect will increment a counter for a throttle source on each engine start during which
the possible throttle source is detected. When the counter for any of the sources indicates five
consecutive detections, the software will set a “confidence flag” to indicate that this is an available
throttle source. Multiple throttle sources can be detected on a single engine start and multiple
confidence flags can be set. There is no limit to the number of engine starts for autodetection of the
throttle source until a confidence flag is set for a source. Once a confidence flag is set for any one of
the sources, a counter begins to countdown for 15 additional engine starts. During the entire
autodetect period, the software will use the highest priority source as the throttle source if multiple
sources are detected before any confidence flags are set. Once a confidence flag is set, that source is
Copyright © 2005 General Motors Corp.
1–13
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
GENERAL DESCRIPTION
used as the source for the throttle signal. When the countdown period is complete, the software will
use the highest priority throttle source having a confidence flag set and the autodetect logic will stop.
D. Engine Coolant Temperature
Engine coolant temperature sensor autodetect will countdown for a total of 25 engine starts while
recording detections of engine coolant temperature sources. A “confidence flag” will be set once a
source is detected for five consecutive engine starts. Multiple sources detected before a confidence
flag is set or multiple confidence flags will result in the highest priority source being used as the
engine coolant temperature source. Multiple sources can be detected on a single engine start cycle.
1–10. TRANSID (TID)
The TransID feature enables the TCM to recognize various transmission hardware configurations and select an
appropriate software calibration. However, if a matching calibration does not exist in memory, the TCM registers a
diagnostic code. Furthermore, TID only works when the controller and transmission have the same generation
controls. Thus, TID will not allow an Allison 4th Generation TCM to recognize a transmission with WTEC III
controls, nor will TID allow a WTEC III ECU to recognize a transmission with Allison 4th Generation Controls.
The TCM senses the transmission configuration using TID wire 176. In initial versions of Allison 4th Generation
Controls, wire 176 is connected to high side driver 1 (HSD1), wire 111, in the internal wiring harness. HSD1
supplies power to PCS6 and MAIN MOD solenoids. This wiring configuration is designated TID A.
Whenever a TID level change is to be made, the new TID level calibration will be added to the PROM Calibration
Configurator System (PCCS) before the change (s) is (are) made in production to the transmissions. All TCMs
programmed and sold after that date will be loaded with the new TID calibration. These TCMs will contain
calibrations for the new level transmission and all previous TID levels and will automatically load the correct
calibration for the transmission based on the TID signal sensed by Autodetect during the first 25 engine starts.
1–14
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
SECTION 2—DEFINITIONS AND ABBREVIATIONS
2–1.
CHECK TRANS LIGHT
When the TCM detects a serious fault, the CHECK TRANS light (usually located on the vehicle instrument panel)
illuminates and action is automatically taken to protect operator, vehicle, and the transmission. A diagnostic trouble
code (DTC) will nearly always be registered when the CHECK TRANS light is on; however, not all diagnostic codes
will turn on the CHECK TRANS light. Codes related to the CHECK TRANS light are detailed in the diagnostic
trouble code chart (refer to Section 6).
Illumination of the CHECK TRANS light indicates that a condition was detected that requires service attention.
Operation may or may not be restricted. Even when operation is restricted, the vehicle can be operated to reach a
service assistance location. Depending upon the cause for the CHECK TRANS light illumination, the TCM may
or may not respond to shift selector requests. The transmission may be locked in a range. That range will be shown
on the shift selector display. Both upshifts and downshifts may be restricted when the CHECK TRANS light is
illuminated. Seek service assistance as soon as possible.
Each time the engine is started, the CHECK TRANS light illuminates briefly and then goes off. This momentary
lighting shows the light circuit is working properly. If the light does not come on during engine start, request
service immediately.
2–2.
ALLISON TRANSMISSION DIAGNOSTIC TOOL
Allison DOC™ (Diagnostic Optimized Connection) For PC–Service Tool is a PC-based diagnostic tool for use
with 3000 and 4000 Product Families transmissions. The Allison DOC™ For PC–Service Tool is a full-feature
diagnostic software application supporting the Allison 4th Generation Control System. When installed on the user’s
own PC, it will allow the technician to acquire data from the transmission’s control system and through the use of
embedded troubleshooting manuals, conduct systematic troubleshooting of transmission complaints.
Basic Features
Allison DOC™ For PC–Service Tool uses a Windows style graphical user interface (GUI) and includes:
•
•
•
•
•
•
•
•
•
•
•
•
User selected views of multiple transmission parameters
Active and historical diagnostic trouble codes (DTCs)
Graphical instrument panel view of transmission parameters
Strip chart function
User configurable Snapshot function
User configurable Print function
Code driven links to embedded Allison 4th Generation Control System Troubleshooting Manuals
Reprogramming capability (available after satisfying Allison Transmission training certification
requirements)
Demo Mode which allows the user to practice the program without being connected to a vehicle
New animated screen by screen help support (found in Help, Video-based training materials, Allison
DOC™ For PC–Service Tool Training Videos)
Application Configuration—This menu function serves as the platform for three different features:
(1) General tab, which allows the user to select language (English only at this time), and unit of measure.
(2) TCM Reprogramming tab, used to enable the reprogramming capability of the Allison DOC™ For
PC–Service Tool.
(3) Update Application tab, will access a web URL that will contain minor updates for the diagnostic
tool to support changes in the various transmission control systems.
Data Bus Viewer allows the user to capture (see and save) the raw data transmitted on the various
vehicle data buses supported by Allison DOC™ For PC–Service Tool (J1939, and J1850)
Copyright © 2005 General Motors Corp.
2–1
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DEFINITIONS AND ABBREVIATIONS
• Printed user’s manual and laminated Job Aid Card
• Adobe Acrobat 5.0 bundled on the CD for reading the Troubleshooting Manual
• Microsoft Media Player 6.4 and 7.0 bundled on the CD for displaying various and updated training
videos (available from the application Help menu).
PC Platform Definition
Allison DOC™ For PC–Service Tool has been tested with and is known to operate on PCs with the following
configurations*:
•
•
•
•
•
•
•
Operating System: Microsoft Windows XP Professional, and Windows 2000 (SP4 or later)
CPU: Pentium III, 800MHz, or Pentium 4, 2.0 GHz (Recommended)
RAM: 128MB RAM, or 256MB RAM or greater (Recommended)
Internet connection capability (Internet Explorer 5.0 or greater)
Hard Drive: 20GB ATA, or 40GB ULTRA ATA/66 or greater (Recommended)
One USB port V1.1, or USB 2.0 (Recommended) 1
CD-ROM: 16x, or 48x Max. Speed or greater (Recommended).
*NOTE:
1.
2.
3.
4.
NOTE:
The Allison DOC™ For PC–Service Tool will not function correctly on PCs not meeting the above
listed definition and will not be supported.
PCCS does not support Windows NT or ME when recalibrating 3000 and 4000 Product Families
transmissions.
PCCS is a separate, stand-alone software application.
For the latest requirements, please refer to www.allisontransmission.com
Additional information available in Appendix N.
1. A serial port (COM1) is required to support the legacy CEC1 controller and for J1850 communications. More information will
be provided in future SILs.
2–2
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DEFINITIONS AND ABBREVIATIONS
2–3.
ABBREVIATIONS
A/N
Assembly Number
ABS
Anti-lock Brake System—OEM-provided means to detect and prevent wheel stoppage to
enhance vehicle handling. Retarder and engine brakes will not apply when ABS is active.
Amp
Unit of electrical current
API
Application Program Interface
AT
Allison Transmission
C1...C6
Clutch 1....Clutch 6
CAN
Controller Area Network—A network for all SAE J1939 communications in a vehicle
(engine, transmission, ABS, etc.)
CIN
Calibration Identification Number
CMC
Customer Modified Constant
CPA
Connector Position Assurance
CT
Closed Throttle
DMM
Digital Multimeter
DNA
Does Not Adapt—Adaptive shift control is disabled
DNS
DO NOT SHIFT—Refers to the DO NOT SHIFT diagnostic response during which the
CHECK TRANS light is illuminated and the transmission will not shift and will not
respond to the Shift Selector
DOC
Diagnostic Optimized Connection
DPA
Dearborn Protocol Adapter
DTC
Diagnostic Trouble Code
DVOM
Digital Volt/Ohmmeter
ECM
Engine Control Module
EMI
ElectroMagnetic Interference
FBO
Feature Based Ordering
FCC
Federal Communications Commission
GPI
General Purpose Input—Input signal to the TCM to request a special operating mode or
condition
GPO
General Purpose Output—Output signal from the TCM to control vehicle components
(such as PTOs, backup lights, etc.) or allow a special operating mode or condition
GUI
Graphical User Interface
HSD
High Side Driver
J1587
Engine/transmission serial data communications link
J1939
High-speed vehicle serial data communications link
LED
Light-Emitting Diode—Electronic device used for illumination
LRTP
Low Range Torque Protection
Copyright © 2005 General Motors Corp.
2–3
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DEFINITIONS AND ABBREVIATIONS
2–3.
ABBREVIATIONS (cont’d)
LSD
Low Side Driver
MB
Mega Byte
NNC
Neutral No Clutches—Neutral commanded with no clutches applied
NVL
Neutral Very Low—The TCM has sensed turbine speed below 150 rpm when output speed
is below 100 rpm and engine speed is above 400 rpm when N (Neutral) was selected. This
is usually caused by a dragging C1 or C3 clutch or a failed turbine speed sensor. NVL is
attained by turning D solenoid “ON” (in addition to E solenoid) and the C4 and C5
clutches are applied to lock the transmission output.
OEM
Original Equipment Manufacturer—Maker of vehicle or equipment
Ohm
Unit of electrical resistance
OL
Over Limit or Oil Level—For Over Limit see “∞”. Indicates Oil Level is being displayed
on a shift selector
OLS
Oil Level Sensor—Electronic device (optional) on control module for indicating
transmission fluid level
PC
Personal Computer
PCCS
PROM Calibration Configurator System
PCS
Pressure Control Solenoid
PLR
Primary Lock Reinforcement (Connector)
P/N
Part Number
PROM
Programmable Read Only Memory
PSS
Primary Shift Selector—Main shift selector in a two-selector control system.
PTO
Power Takeoff
PWM
Pulse Width Modulation
RELS
Reduced Engine Load at Stop
RFI
Radio Frequency Interference
RMR
Retarder Modulation Request—Signal from a retarder control device
RPR
Return to Previous Range—Diagnostic response in which the transmission is commanded
to return to previously commanded range
SCI
Serial Communication Interface—Used to transmit data and messages between the
diagnostic tool and the TCM and other systems such as electronically-controlled engines.
SCTI
St. Clair Technologies, Inc.
SEM
Shift Energy Management
S/N
Serial Number
SOH
State Of Health
SOL OFF
All SOLenoids OFF
SPI
Serial Peripheral Interface—The means of communication between the microprocessor
and the interface circuits
2–4
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DEFINITIONS AND ABBREVIATIONS
2–3.
ABBREVIATIONS (cont’d)
SS
Shift Solenoid
SSS
Secondary Shift Selector—Alternate shift selector in a two-selector control system
TCC
Torque Converter Clutch
TCM
Transmission Control Module
TFT
Transmission Fluid Temperature
TID
TransID—A feature which allows the TCM to know the transmission configuration and
provide the corresponding calibration required
TPA
Terminal Position Assurance
TPS
Throttle Position Sensor—Potentiometer for signaling the position of the engine fuel
control lever
V
Version—Abbreviation used in describing TCM software levels
VDC
Volts Direct Current (DC)
VF
Vacuum Fluorescent
VIM
Vehicle Interface Module—A watertight box containing relays and fuses—interfaces the
transmission electronic control system with components on the vehicle
VIW
Vehicle Interface Wiring—Interfaces TCM programmed input and output functions with
the vehicle wiring
Volt
Unit of electrical force
WOT
Wide Open Throttle
∞
Infinity—Condition of a circuit with higher resistance than can be measured, effectively an
open circuit
Copyright © 2005 General Motors Corp.
2–5
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
SECTION 3—BASIC KNOWLEDGE
3–1.
BASIC KNOWLEDGE REQUIRED
To service Allison 4th Generation Controls, the technician must understand basic electrical concepts. Most
troubleshooting checks consist of checking resistance, continuity, and checking for shorts between wires and to
ground. Technicians need to know how to use a digital volt/ohmmeter (DVOM) to make resistance and continuity
checks. The technician should be able to use jumper wires and breakout harnesses and connectors. Technicians
unsure of making the required checks should ask questions of experienced personnel or find instruction.
The technician should also have the mechanical aptitude required to connect pressure gauges or transducers to
identified pressure ports used in the troubleshooting process. Pressure tap locations and pressure values are shown
in Appendix B—Checking Clutch Pressures.
Input power, ground, neutral start circuitry, etc., can cause problems with electronic controls or vehicle functioning
and may not generate a diagnostic code. A working knowledge of the Allison 4th Generation Controls vehicle
installation is necessary in troubleshooting installation-related problems.
Refer to Section 8 for information concerning performance complaints (non-code) troubleshooting. A complete
wiring schematic is shown in Appendix J. Refer to the Allison 4th Generation Controls and General Information
Sales Tech Data Book for information concerning electronic controls installation and the Installation Checklist.
Reliable transmission operation and performance depend upon a correctly installed transmission. Review the
Installation Checklist in the 3000 and 4000 Product Families transmissions Tech Data Books for proper
installation.
NOTE:
Allison Transmission is providing for service of wiring harnesses and wiring harness components as
follows:
• Repair parts for the internal wiring harness and for wiring harness components attached to the
shift selector will be available through the Allison Transmission Parts Distribution Center (PDC).
Use the P/N from your appropriate parts catalog or from Appendix E in this manual. Allison
Transmission is responsible for warranty on these parts.
• Repair parts for the external harnesses and external harness components must be obtained from
St. Clair Technologies Inc. (SCTI). SCTI provides parts to any Allison customer or OEM and is
responsible for warranty on these parts. SCTI recognizes Allison Transmission, manufacturers,
and SCTI part numbers. SCTI provides a technical HELPLINE at 519-627-1673 (Wallaceburg).
SCTI will have parts catalogs available. The SCTI addresses and phone numbers for parts
outlets are:
St. Clair Technologies, Inc.
920 Old Glass Road
Wallaceburg, Ontario, Canada N8A 4L8
Phone: 519-627-1673
Fax: 519-627-4227
3–2.
St. Clair Technologies, Inc.
Calle Damanti S/N Col
Guadalupe—Guaymas
Sonora, Mexico 85440
Phone: 011-526 2222-43834
Fax: 011-526-2222-43553
USING THE TROUBLESHOOTING MANUAL
Use this manual as an aid to troubleshooting the Allison 4th Generation Controls. Every possible problem and its
solution cannot be encompassed by any manual. However, this manual does provide a starting point from which
most problems can be resolved.
Once a problem solution is discovered in the manual do not look further for other solutions. It is necessary to
determine why a problem occurred. The root cause of a problem as well as the symptom must be corrected to be
sure of trouble-free operation. For example, taping a wire that has been rubbing on a frame rail will not correct the
problem unless the rubbing contact is eliminated.
Copyright © 2005 General Motors Corp.
3–1
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
BASIC KNOWLEDGE
3–3.
SYSTEM OVERVIEW
Allison 4th Generation Control functions are controlled by the TCM. The TCM reads the following to determine
when to command a shift:
• Shift selector range selection
• Output speed
• Throttle position.
In order to control the oncoming and off-going clutches during a shift, the TCM monitors:
• Turbine speed
• Output speed
• Throttle position.
When the TCM detects an electrical fault, it logs a diagnostic code indicating the faulty circuit and may alter the
transmission operation to prevent or reduce damage.
When the TCM detects a non-electrical problem while trying to make a shift, the TCM may try that shift a second
or third time before setting a diagnostic code. Once that shift has been retried, and a fault is still detected, the TCM
sets a diagnostic code and holds the transmission in a fail-to-range mode of operation.
3–4.
IMPORTANT INFORMATION IN THE TROUBLESHOOTING PROCESS
A.
Before Beginning Troubleshooting
Before beginning the troubleshooting process, read and understand the following:
• Allison Transmission recommended wire numbers (i.e. 158) all use a “1” for the first digit and the
pin-out information at the TCM for the second and third digits.
• Shut off the engine and ignition before any harness connectors are disconnected or connected.
• Remember to do the following when checking for shorts and opens:
— Minimize movement of wiring harnesses when looking for shorts. Shorts involve wire-to-wire
or wire-to-ground contacts and moving the harnesses may eliminate the problem.
— Wiggle connectors, harnesses, and splices when looking for opens. This simulates vehicle
movements which occur during actual operation.
• When disconnecting a harness connector, be sure the pulling force is applied to the connector itself
and not the wires extending from the connector.
• Resistance checks involving wiring between the TCM connector and other components adds about
one Ohm of resistance to the component resistance shown.
• Inspect all connector terminals for damage. Terminals may have been bent or lost the necessary
tension to maintain firm contact.
• Clean dirty terminals or connectors with isopropyl alcohol and a cotton swab, or a good quality,
non-residue, non-lubricating, cleaning solvent such as LPS Electro Contact Cleaner® or LPS
NoFlash Electro Contact Cleaner®.
3–2
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
BASIC KNOWLEDGE
The cleaning solvent must not be:
• Chlorine based
• Contain petroleum distillates
CAUTION:
CAUTION:
• Conduct electricity.
The cleaning solvent should evaporate quickly to prevent the possibility of
condensation within the connectors. Always blow or shake any excess cleaner from
the connector before assembling it to its mating connector or hardware. Cleaner
trapped in the connector can affect the connector seal. Refer to SIL 17-TR-94, latest
revision, for detailed information on the recommended cleaners.
Care should be taken when welding on a vehicle equipped with electronic controls.
Refer to Appendix G, Paragraph 1–1.
• Diagnostic codes displayed after system power is turned on with a harness connector disconnected,
can be ignored and cleared from memory. Refer to Section 6, Diagnostic Codes, for the code
clearing procedure.
NOTE:
Turn off the vehicle HIGH IDLE switch, if present, before shifting from N (Neutral) to D (Drive).
D (Drive) or R (Reverse) will not be attained unless the shift is made with the engine at idle. Also, be
aware of other interlocks that would prevent attaining D (Drive) or R (Reverse). Examples are
“wheelchair lift not stored” and “service brakes not applied” (service brake interlock present).
B.
Cold Weather Starts
All Highway Series transmissions are programmed to restrict full operation until specific fluid
temperatures are reached. Refer to the Table 3–1 for temperature restrictions.
Table 3–1. Minimum Fluid Operating Temperatures
Sump Fluid Temperature
–32ºC to –7ºC (–25ºF to 19ºF)
–7ºC (19ºF)
NOTE:
CHECK TRANS
Light
Operation
OFF
Neutral, Reverse, Second
OFF
Full operation in all ranges
When sump temperature is below 10ºC (50ºF) and transmission fluid is C4 (not DEXRON® or
TranSynd™), follow these procedures when making directional shift changes:
• To shift from forward to reverse, select N (Neutral) and then R (Reverse).
• To shift from reverse to forward, select N (Neutral) and then D (Drive) or other forward range.
Failure to follow these procedures may cause illumination of the CHECK TRANS light and the
transmission will be restricted to N (Neutral).
Transmission operation at cold ambient temperatures may require preheating or the use of a lower
viscosity transmission fluid.
Copyright © 2005 General Motors Corp.
3–3
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
BASIC KNOWLEDGE
C.
High Fluid Temperature
The transmission is considered to be overheated when any of the temperatures in Table 3–2 are
exceeded:.
Table 3–2. Overheated Transmission Fluid Temperatures
Location of Fluid
Temperature
Sump fluid
121ºC (250ºF)
Fluid to cooler
149ºC (300ºF)
Retarder out fluid
165ºC (330ºF)
If the transmission overheats during normal operation, measure the fluid level in the transmission.
Refer to the Transmission Fluid Check procedure in the appropriate transmission mechanic’s tips
manual.
CAUTION:
The engine should never be operated for more than ten (10) seconds at full throttle
with the transmission in range and the output stalled. Prolonged operation of this
type will cause the transmission fluid temperature to become excessively high and
will cause severe overheat damage to the transmission.
If the engine temperature gauge indicates a high temperature, the transmission is probably
overheated. Stop the vehicle and inspect the cooling system. If it appears to functioning p[roperly, run
the engine at 1200–1500 rpm with the transmission in N (Neutral). This should reduce the
transmission and engine temperature to normal operating levels in two to three minutes. If
temperatures do not decrease, reduce the engine rpm.
If the engine temperature indicates a high temperature, an engine or radiator problem is indicated. If
high temperature in either the engine or transmission persists, stop the engine and have the
overheating condition investigated by maintenance personnel.
3–5.
BEGINNING THE TROUBLESHOOTING PROCESS
NOTE:
Whenever a transmission is overhauled, exchanged, or has undergone internal repairs, the TCM
MUST BE RESET TO FACTORY VALUES by selecting “Reset To Unadapted Shifts” (all), and “Reset
Autodetect Information” in Allison DOC For PC–Service Tool.
1.
Begin troubleshooting by determining the transmission fluid level and TCM input voltage. Remember
that some problems may be temperature related. Do troubleshooting at the temperature level where
the problem occurs. Check diagnostic codes by:
• Using the shift selector display (see Paragraph 6–2 for code reading).
• Using the Allison DOC For PC–Service Tool.
2.
3–4
When a problem exists but a diagnostic code is not indicated, refer to the Performance Complaint
Section (Section 8) for a listing of various electrical and hydraulic problems, their causes, and remedies.
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
BASIC KNOWLEDGE
3.
If a diagnostic code is found in the TCM memory, record all available code information and clear the
active indicator. Refer to Section 6.
4.
Test drive the vehicle to confirm a diagnostic code or performance complaint.
• If the code reappears, refer to the Diagnostic Code section (Section 6) and the appropriate code
chart. The Diagnostic Code section lists diagnostic codes and their description. Locate the
appropriate troubleshooting chart and follow the instructions.
• If the code does not reappear, it may be an intermittent problem. Use the Allison DOC For PC–
Service Tool and the code display procedure described in Section 6. The code display procedure
will indicate the number of times the diagnostic code has occurred. Refer to the troubleshooting
chart for the possible cause(s) of the problem.
• Appendix A deals with the identification of potential circuit problems. Refer to Appendix A if a
circuit problem is suspected.
5.
If difficulties arise, you have unanswered questions, or if you are unable to quickly identify the root
cause during troubleshooting, please contact the Technical Assistance Center (TAC):
Technical Assistance Center
PO Box 894, Mail Code 462-470-PF9
Indianapolis, IN 46206-0894
Phone: 1-800-252-5283
NOTE:
3–6.
Information concerning specific items is contained in the appendices located in the back of this
manual. The appendices are referred to throughout the manual.
TCM DIAGNOSTIC PROCEDURE
• Use the Allison DOC For PC–Service Tool to verify the current calibration information number (CIN)
and record or print a report of the current customer modifiable constants (CMC) information for later
reference.
• Remove the 80-way connector from the suspect TCM; inspect the connector for damaged or bent pins.
• Replace the TCM with a known, good TCM from a similar vehicle.
NOTE:
If using a TCM from another vehicle is unavoidable, the TCM MUST BE set to factory values and the
vehicle MUST BE driven carefully to adapt the shifts to the test vehicle. Refer to SIL 16-WT-96 for the
correct procedure. Be sure to reset the Adaptive Shift parameters and Autodetect information when it
is installed in the original vehicle.
• If the replacement TCM corrects the original complaint, reinstall the original TCM to verify that the
complaint returns. If the complaint is confirmed. install a new TCM.
• If the complaint does not return, leave the original TCM installed. Disconnecting and reconnecting the
TCM can often correct faulty wiring harness connections that may have been present.
• Clear any diagnostic codes that may be present and test drive the vehicle to confirm the repair.
NOTE:
All Allison 4th Generation Controls TCMs are designed to be isolated from the vehicle chassis ground.
Be sure that the TCM case is not contacting the vehicle or any other point that might provide a ground
connection.
Copyright © 2005 General Motors Corp.
3–5
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
BASIC KNOWLEDGE
3–7.
RESETTING OF TCM PARAMETERS TO SUPPORT ENGINE UPDATE
Shift Energy Management (SEM) Autoselect feature may be used on certain transmissions. Autoselect is
deactivated following the first 20 engine starts where engine and transmission communication are present. If
during the first 20 starts the TCM recognizes an engine to be on its list of certified engines, it will lock to the SEM
active state. If the engine is not supported, the TCM will lock to a non-SEM state.
NOTE:
Most engine upgrades are same type/rating; under normal circumstances there should be no reason
to reset the TCM Autoselect.
However, there may be a small chance that transmission performance, shift quality, or codes may result from the
use of different models within the same engine family or when a recalibration of engine software has taken place. If
a vehicle receives upgraded engine hardware or software it may become necessary to reactivate the Autoselect
feature to redetect the engine current SEM status.
NOTE:
3–8.
Once TCM Autoselect locks, the only way to reactivate is to perform a reset procedure (refer to
Paragraph 3–8).
RESETTING TCM AUTOSELECT
Verify a new engine rating by checking the engine data tag. The engine must be compatible with the transmission
rating. If engine rating is not compatible, the vehicle must be returned to the OEM for engine recalibration. If the
rating is correct for the transmission, perform the following steps.
Allison DOC for PC–Service Tool is used to reset Autoselect function as follows:
• Display the Action Request menu.
• On the drop down menu, select Reset SEM Autodetect.
• Click on the OK button.
The TCM is now reset to Autoselect and will start looking for supporting engine software. Drive the vehicle;
confirm DTCs have not returned.
NOTE:
3–6
Transmission shifts will now be in the unadaptive (base) state, so it will be necessary to drive the
vehicle to allow shift to converge.
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
SECTION 4—WIRE TEST PROCEDURES
4–1.
TESTING FOR OPENS, SHORTS BETWEEN WIRES, AND SHORTS-TO-GROUND
(Use Digital Volt/Ohmmeter J 34520-A and Jumper Wire Set J 39197)
NOTE:
Please refer to Paragraph 3–5 to begin the troubleshooting process.
1.
Make sure all connectors are tightly connected and re-test the circuit.
2.
Disconnect and inspect all connectors.
CAUTION:
3.
Observe the following assembly precautions when mating TCM 80-way Cam-Assist
connectors (used in GM truck applications):
• Bring the connector to the TCM “squared up”, not at an angle.
• Keep hands away from the handle, squarely press the connector onto the
TCM until the cam lever handle moves of its own accord approximately
3⁄4 inch.
• Gently complete mating the connector to the TCM by moving the cam lever
handle to the locked position.
• Slide the CPA into the secondary lock.
Failure to do so could cause damage to the internal latching mechanism.
Thoroughly clean corroded or dirty terminals. If dirty or corroded terminals are the probable cause of
the problems, reconnect the clean connectors and operate the vehicle normally. If the problem recurs,
proceed with Step (4).
CAUTION:
The cleaning solvent must not be:
• Chlorine based
• Contain petroleum distillates
• Conduct electricity.
The cleaning solvent should evaporate quickly to prevent the possibility of
condensation within the connectors. Always blow or shake any excess cleaner from
the connector before assembling it to its mating connector or hardware. Cleaner
trapped in the connector can affect the connector seal. Refer to SIL 17-TR-94,
latest revision, for detailed information on the recommended cleaners.
4.
Review the Allison 4th Generation Controls wire numbering system described in Paragraph 3–4.
5.
If all connectors are clean and connected correctly, determine which wires in the chassis harness are
indicated by the diagnostic code. For example, Code P0960, indicates an open in the pressure control
solenoid circuit, wires 111 and 174.
a. Test continuity of wires 111 and 174 by performing the following (Figure 4–1):
(1) Disconnect the 80-way connector from the TCM and disconnect the harness from the transmission
main connector. At one end of the harness, using jumper wire kit J 39197, connect wires 111 and
174 to each other, being careful not to distort the terminals. Jumpering the wires together creates a
circuit between wires 111 and 174.
CAUTION:
Do not insert test probes larger than 0.81 mm into the TCM 80-way and
transmission 20-way connectors. Use the gray-colored 150 Series Metripack
Flexible Male Connector probe contained in Jumper Wire Kit J 39197 when testing
the TCM and transmission mating connectors. Failure to do so may distort the
socket terminals inside the connectors and cause them to lose the necessary tension
to maintain firm contact.
Copyright © 2005 General Motors Corp.
4–1
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
WIRE TEST PROCEDURES
(2) On the opposite end of the harness, test the continuity of the jumpered pair. No continuity in a
jumpered pair circuit (infinite resistance reading) indicates an open in the wire being tested.
Locate and repair the damaged portion of the wire.
b. If the continuity test is good (0–2 Ohms resistance), remove the jumpers. Check the harness for
shorts between wires and shorts-to-ground by performing the following (Figure 4–2):
(1) At the TCM end of the harness, touch one probe of a DVOM to one wire of the circuit being
tested and touch the other probe to each terminal in the same connector, then touch the probe
to chassis ground and to the transmission main housing. Do this for both wires in the circuit
being tested.
(1) If at any time the DVOM shows zero to low resistance, or the meter’s continuity beeper sounds,
there is a short between the two points being probed—wire-to-wire or wire-to-ground. Isolate
and repair the short.
BULKHEAD CONNECTOR
WIRING HARNESS
JUMPER
FEEDTHROUGH
HARNESS
CONNECTOR
DIGITAL
VOLT/OHM-METER
(DVOM)
0
0
–
–
0 OHMS
+
OHMS
+
Circuit does not have continuity due
to a broken wire (open circuit).
DVOM reading is very high
(infinite Ohms or OL – overlimit).
Circuit has continuity.
Jumper between wires produces
a complete circuit.
DVOM reading is near zero Ohms.
V03374.02.00
Figure 4–1. Open Circuit
TRANSMISSION CONNECTOR
WIRING HARNESS
Wires shorted
together
0
–
Shorted to
ground on
metal frame
rail
0
TCM
80-WAY
CONNECTOR
+
Ground
to metal
frame rail
–
+
DIGITAL VOLT/OHM-METER
(DVOM)
0 OHMS
0 OHMS
Two wires have frayed and are shorted together.
Continuity beeper of DVOM will sound,
or reading will go to zero Ohms when these
two wires are probed with the DVOM.
Harness has been chafed and one or more wires are
shorted-to-ground. DVOM continuity beeper will sound,
or reading will go to zero Ohms when meter is probing
between this wire and chassis ground.
V03375.01.00
Figure 4–2. Short Between Wires and to Ground
4–2
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
WIRE TEST PROCEDURES
4–2.
TESTING AT TRANSMISSION FEEDTHROUGH CONNECTOR FOR INTERNAL
HARNESS OPENS, SHORTS BETWEEN WIRES, AND SHORTS-TO-GROUND
1.
2.
Disconnect the external wiring harness from the transmission.
Inspect the connectors. Any terminals which are corroded or dirty must be thoroughly cleaned.
The cleaning solvent must not be:
• Chlorine based
• Contain petroleum distillates
• Conduct electricity.
The cleaning solvent should evaporate quickly to prevent the possibility of
condensation within the connectors. Always blow or shake any excess cleaner from
the connector before assembling it to its mating connector or hardware. Cleaner
trapped in the connector can affect the connector seal. Refer to SIL 17-TR-94,
latest revision, for detailed information on the recommended cleaners.
CAUTION:
3.
If the connectors are clean and connected correctly, determine which wires in the harness to test.
Use the diagnostic code system schematic to locate the wire terminals. For this example, Code P0960
indicates an open in the Main Mod solenoid circuit, wires 111 and 174 (Figures 4–3 and 4–4).
a. At the transmission connector, test the resistance of Main Mod solenoid circuit. Resistance of a
solenoid circuit should be 4.0 to 7.8 Ohms, covering a temperature range of –20°C to 140°C
(–4°F to 284°F). Refer to Solenoid Resistance vs. Temperature chart in Appendix K. No
continuity in the circuit (infinite resistance) indicates an open in the internal harness, the
feedthrough connector, or the solenoid coil. Locate and repair the open in the internal harness or
replace the internal harness, replace the feedthrough connector, or the solenoid.
FEEDTHROUGH
HARNESS
CONNECTOR
LOCATED IN
INTERNAL
WIRING HARNESS
5.0
OL
–
–
+
+
DIGITAL
VOLT/OHM-METER
(DVOM)
SOLENOID
SOLENOID
2–5 OHMS
AT NORMAL OPERATING
TEMPERATURE*
Circuit has continuity.
* Refer to Appendix J
INFINITE (
) OHMS
Circuit does not have continuity due to a
broken wire (open circuit). DVOM reading is
very high (infinite ohms or OL–overlimit).
This could also be due to an open solenoid
coil or bad connection.
V03376.01.00
Figure 4–3. Checking Continuity
Copyright © 2005 General Motors Corp.
4–3
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
WIRE TEST PROCEDURES
b. If the resistance test is good, test the harness for shorts between wires and to ground by performing
the following (Figure 4–4):
(1) At the transmission connector, touch one probe of the DVOM to one wire of the circuit being
tested and touch the other probe to each terminal in the connector and to chassis ground and
the transmission main housing. Do this for both wires in the circuit being tested.
(2) If the DVOM shows zero to low resistance, or the continuity beeper sounds, there is a short
between the two points being probed, wire-to-wire or wire-to-ground. An indication of a short
may be caused by a splice to the wire being checked. Review the wiring diagram in Appendix
J for splice locations. If the short is not a splice, then isolate and repair the short.
SOLENOIDS
LOCATED IN INTERNAL
WIRING HARNESS
FEEDTHROUGH
HARNESS
CONNECTOR
0
Shorted
to metal
0
Bare wires
touching
each other
–
SOLENOID
–
+
+
DIGITAL
VOLT/OHM-METER
(DVOM)
0 OHMS
0 OHMS
Two wires have frayed and are shorted together.
Continuity beeper of DVOM will sound,
or reading will go to zero Ohms when these
two wires are probed with the DVOM.
Harness has been chafed and one or more wires are
shorted-to-ground. DVOM continuity beeper will sound,
or reading will go to zero Ohms when meter is probing
between this wire and chassis ground.
V03377.01.00
Figure 4–4. Short Between Wires and to Ground
NOTE:
4–4
When conducting circuit tests that include the external harness, add one (1) Ohm to the values shown.
Speed sensor resistance is 270–330 Ohms. PS1 diagnostic pressure switch resistance is two (2) Ohms
maximum when switch is closed and 20,000 Ohms minimum when switch is open.
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
SECTION 5—OIL LEVEL SENSOR (OLS)
5–1.
INTRODUCTION
The oil level sensor (Figure 5–1) provides a means of electronically checking the transmission fluid level from:
• The shift selector display
• Allison DOC For PC–Service Tool
• A customer-furnished remote display.
V07087.01.00
Figure 5–1. Oil Level Sensor
The Allison 4th Generation Controls oil level sensor (OLS) is a one-piece unit with a molded 3-terminal connector
built into the sensor housing (see Figure 5–1 and SIL 19-WT-99 for more details). The internal wiring harnesses
have been designed to include the 3-terminal connector for the OLS.
NOTE:
The OLS is standard on all 3000 and 4000 Product Families transmissions except 3000 Product
Family 7-speed transmissions.
Figure 5–2 shows the position and orientation of the OLS on the control modules of the 3000 and 4000 Product
Families transmissions. The OLS must be correctly positioned so the internal harness connector reaches the
connector on the sensor. The control module must fit onto the transmission main case without interference. The one
piece design reduces the complexity of the manufacturing and installation of the sensor. The current OLS uses
shoulder bolts and Viton® ferrules to provide vibration dampening in the mounting.
Copyright © 2005 General Motors Corp.
5–1
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
OIL LEVEL SENSOR (OLS)
OIL LEVEL SENSOR
6-SPEED
3000 PRODUCT FAMILY
CONTROL MODULE
OIL LEVEL SENSOR
OIL LEVEL SENSOR
6-SPEED
4000 PRODUCT FAMILY
CONTROL MODULE
7-SPEED
4000 PRODUCT FAMILY
CONTROL MODULE
V09271.00.00
Figure 5–2. Current Oil Level Sensor Orientation
5–2
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
OIL LEVEL SENSOR (OLS)
5–2.
ELECTRONIC FLUID LEVEL READING (SHIFT SELECTOR)
CAUTION:
NOTE:
A low or high fluid level causes overheating and irregular shift patterns. An incorrect
fluid level can damage the transmission.
The pushbutton and lever shift selectors can display two characters at a time. The strip pushbutton
shift selector does not have diagnostic or display capability. Allison DOC™ For PC–Service Tool or a
customer-furnished remote display must be used to obtain fluid level information when using the strip
pushbutton shift selector.
A.
Fluid Level Reading Procedure
1. Park the vehicle on a level surface and shift to N (Neutral). Apply the parking brake.
2. On the Pushbutton shift selector, simultaneously press the ↑ (Up) and ↓ (Down) arrow buttons once.
3. On the Lever shift selector, press the “display mode” button once.
4. For a strip pushbutton shift selector, refer to Allison publication GN3433EN, User Guide for
Allison DOC For PC–Service Tool.
NOTE:
The TCM may delay the fluid level reading until the following conditions are met:
• The fluid temperature is between 60°C (140°F) and 104°C (220°F).
• The transmission is in N (Neutral).
• The vehicle has been stationary for approximately two minutes to allow the fluid to settle.
• The engine is at idle (below 1000 rpm—not “fast” idle).
See “Invalid for Display” information in Steps (8) and (9).
5. Correct fluid level is reported when o L is displayed (o L indicates the Oil Level Check Mode), followed by o K. The o K display indicates the fluid level is within the proper fluid level zone. The
sensor display and the transmission dipstick may not agree exactly because the oil level sensor compensates for fluid temperature.
Example: o L; o K—Indicates correct fluid level.
6. Low fluid level is reported when o L is displayed, followed by L o and a number. L o indicates a
low fluid level and the number is the number of quarts of fluid the transmission requires.
Example: o L; L o; 2—Indicates two (2) additional quarts of fluid will bring the fluid level within
the proper fluid level.
Copyright © 2005 General Motors Corp.
5–3
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
OIL LEVEL SENSOR (OLS)
7. High fluid level is reported when o L is displayed, followed by H I and a number. H I indicates high
fluid level and the number shows how many quarts the transmission is overfilled.
Example: o L, H I, 1—Indicates one quart of fluid above the full level.
8. An Invalid for Display condition is reported when o L is displayed, followed by “–” and a number
display. The displayed number is a fault code and indicates improper conditions or a system
malfunction.
Example: o L, –, 7 0—Indicates an Invalid for Display condition and fault code 70.
9. Invalid for Display is activated when conditions do not allow the fluid level to be checked
electronically. Review the following codes and conditions, and correct as necessary.
Table 5–1. Invalid for Display Codes
CODE
X*
50
59
65
70
79
89
95
CAUSE OF CODE
—
Settling time too short
—
Engine speed (rpm) too low
—
Engine speed (rpm) too high
—
N (Neutral) must be selected
—
Sump fluid temperature too low
—
Sump fluid temperature too high
—
Output shaft rotation
—
Sensor failure**
* A number between 8 and 1 that flashes during the countdown period.
** Speed sensor, throttle sensor, temperature sensor, or oil
level sensor.
10. To exit the fluid level display mode:
• Pushbutton shift selector—press the N (Neutral) pushbutton or press ↑ (Up) and ↓ (Down)
arrow pushbuttons simultaneously two times.
• Lever shift selector—press the “DISPLAY MODE” button two times or move the lever.
5–4
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
OIL LEVEL SENSOR (OLS)
5–3.
ELECTRONIC FLUID LEVEL READING (ALLISON DOC™ FOR PC–SERVICE
TOOL)
Allison DOC For PC–Service Tool can also be used to electronically read the transmission’s fluid level (refer to
Allison publication GN3433EN, User Guide for Allison DOC For PC–Service Tool for further information).
CAUTION:
A.
A low or high fluid level causes overheating and irregular shift patterns and, if not
corrected, can damage the transmission.
Fluid Level Check Procedure
1. Connect the Allison DOC For PC–Service Tool to the diagnostic tool connector (Figure 1–2).
2. Select Diagnostic button.
3. Scroll down the Diagnostic Data List to “Custom Data Monitor” display.
4. Select “oil level deviation.”
5. Read the fluid level deviation, repeat the reading to confirm the first reading.
NOTE:
The TCM may delay the fluid level reading until the following conditions are met:
• The fluid temperature is between 60°C (140°F) and 104°C (220°F).
• The transmission is in N (Neutral).
• The vehicle has been stationary for approximately two minutes to allow the fluid to settle.
• The engine is at idle.
The reason for a delayed fluid level reading is indicated on the Allison DOC For PC–Service Tool by one of the
following diagnostic messages.
Table 5–2. Diagnostic Message
OL —
SETTLING TIME (8 down to 1)
OL —
ENGINE SPEED LO
OL —
ENGINE SPEED HI
OL —
SELECT N (NEUTRAL)
OL —
SUMP TEMP LO
OL —
SUMP TEMP HI
OL —
OUTPUT SPEED HI
OL —
CHECK CODES
Copyright © 2005 General Motors Corp.
5–5
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
SECTION 6—DIAGNOSTIC TROUBLE CODES (DTC)
6–1.
DIAGNOSTIC CODE MEMORY
Diagnostic codes are logged in a list in memory (sometimes referred to as the queue), listing the most recently
occurring code first and logging all active and inactive codes. The codes contained in the list have information
recorded as shown in the table below (codes are examples). Access to the code list position, DTC, and active
indicator is through the shift selector display. The shift selector will display only five codes, beginning with the
most recent active followed by the most recent inactive DTCs. Access to DTC, Active indicator, Historic indicator,
Check Trans indicator, Failure Record indicator, and Description is through the Allison DOC For PC–Service
Tool. Further details on the use of the Allison DOC™ For PC–Service Tool are presented in GN3433EN User
Guide furnished with each tool.
Table 6–1. Code List
Code List
Position*
DTC
Active**
Historic
Check
Trans
Failure
Record
Description
d1
d2
d3
d4
d5
P0880
P2723
P0727
P0610
—
Y
Y
N
N
—
Y
Y
Y
Y
—
N
Y
N
N
—
Y
Y
Y
Y
—
TCM Power Input Signal
Pressure Control Solenoid 1 Stuck Off
Engine Speed Input Circuit No Signal
TCM Vehicle Options (TransID) Error
—
* Displayed on shift selector only, d = diagnostic
** On shift selector, Y = Mode indicator (LED) illuminated
The following paragraphs define the different parts of the code list.
A.
Code List Position (shift selector only). The position which a code occupies in the code list.
Positions are displayed as “d1” through “d5” (Code List Position 1 through Code List Position 5).
B.
DTC. The diagnostic trouble code number referring to the general condition or area of fault detected
by the TCM. “Double click” on the numerical code in the DTC column to link to the specific
troubleshooting instructions for the DTC.
C.
Active Indicator. Indicates when a diagnostic code is active. The MODE indicator LED on the shift
selector is illuminated or the diagnostic tool displays Y when DTC is active.
D.
Historic Indicator. Indicates when the DTC has met sufficient criteria to be stored in long term
memory. “Sufficient criteria” may mean the DTC occurred over a specific span of time or over
multiple test cycles.
E.
Check Trans Indicator. Indicates when the TCM is requesting the CHECK TRANS light as a result
of the DTC.
F.
Failure Records Indicator. Indicates when Failure Records are present. “Double click” on Y in the
Failure Records column to display failure record information.
G.
Description. Provides a brief description of the DTC. “Double click” on the DTC description to link
to the specific troubleshooting instructions for the DTC.
Copyright © 2005 General Motors Corp.
6–1
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
6–2.
CODE READING AND CODE CLEARING
Diagnostic codes can be read and cleared by the following methods:
•
Allison DOC™ For PC–Service Tool.
•
Diagnostic display mode on the shift selector.
The use of Allison DOC™ For PC–Service Tool is described in Allison publication GN3433EN, User Guide, that
is furnished with each tool. The method of reading and clearing codes described in this section refers to entering
the diagnostic display mode of the shift selector.
The diagnostic display mode may be entered for viewing of codes at any speed. Active codes can only be cleared
when the output speed = 0 and no output speed sensor failure is active.
A.
Reading Codes. Enter the diagnostic display mode by pressing the ↑ (Up) and ↓ (Down) arrow
buttons at the same time on a pushbutton selector, or by momentarily pressing the MODE button on a
lever shift selector.
NOTE:
If a DO NOT SHIFT condition is present (CHECK TRANS light illuminated) at this time, the shift
selector may or may not respond to requested range changes.
NOTE:
If an oil level sensor is present, then fluid level will be displayed first. Diagnostic code display is
achieved by simultaneously depressing the ↑ (Up) and ↓ (Down) arrow buttons a second time or the
MODE button a second time.
The code list or queue position is the first item displayed, followed by the DTC. Each item is displayed for about
one second. The display cycles continuously until the next code list position is accessed by pressing the MODE
button. The following example shows how DTC C1312 is displayed on the pushbutton and lever shift selectors:
SELECT
MONITOR
d
1
C
3
2
1
1
To view the second, third, fourth, and fifth positions (d2, d3, d4, and d5), momentarily press the MODE button as
explained above.
Momentarily press the MODE button after the fifth position is displayed to restart the sequence of code list
positions.
An active code is indicated by the illumination of the LED indicator when a code position is displayed while in the
diagnostic display mode. In the normal operating mode, the LED indicator illuminates to show a secondary mode
operation.
Any code position which does not have a diagnostic code logged will display “–” for the DTC. No diagnostic codes
are logged after an empty code position.
B.
Clearing Active Indicators. A diagnostic code’s active indicator can be cleared, which allows the
code inhibit to be cleared but remains in the queue as inactive.
The active indicator clearing methods are:
1. Power down—All active indicators are cleared at TCM power down.
6–2
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
2. Self-clearing—Some codes will clear their active indicator when the condition causing the code is
no longer detected by the TCM.
3. Manual—Some active indicators can be cleared manually, while in the diagnostic display mode,
after the condition causing the code is corrected.
CAUTION:
C.
If an active indicator is cleared while the transmission is locked in a forward range
or reverse (fail-to-range), the transmission will remain in the forward range or
reverse after the clearing procedure is completed. Neutral must be manually
selected.
Manually Clearing Codes and Active Indicators from the Code List. To clear active indicators or
all codes:
1. Enter the diagnostic display mode.
2. Press and hold the MODE button for approximately ten seconds until the LED indicator flashes. All
active and inactive indicators are cleared. All active indicators will be cleared at TCM power down.
3. Codes that cannot be manually cleared will remain.
D.
Exiting the diagnostic display mode. Exit the diagnostic display mode using one of the following
procedures:
1. On a pushbutton shift selector, press the ↑ (Up) and ↓ (Down) arrow buttons at the same time or
press any range button, D, N, or R. The shift (D, N, or R) is commanded if not inhibited by an
active code.
2. On a lever shift selector, momentarily press the MODE button or move the shift lever to any shift
position other than the one it was in when the diagnostic display mode was activated. If the shift is
inhibited, the TCM will continue to command the current transmission range attained and the lever
should be returned to its original position.
3. Wait until timeout (approximately 10 minutes) and the system will automatically return to the normal operating mode.
4. Turn off power to the TCM (turn off the vehicle engine at the ignition switch).
6–3.
DIAGNOSTIC CODE RESPONSE
The following TCM responses to a fault provide for safe transmission operation:
•
Do Not Shift (DNS) Response
— Release lockup clutch and inhibit lockup operation.
— Inhibit all shifts.
— Turn on the CHECK TRANS light.
— Display the range attained.
— Ignore any range selection inputs from the pushbutton or lever shift selector.
• Do Not Adapt (DNA) Response
— The TCM stops adaptive shift control while the code is active. Do not adapt shifts when a code with
the DNA response is active.
Copyright © 2005 General Motors Corp.
6–3
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
•
SOLenoid OFF (SOL OFF) Response
— All solenoids are commanded off (turning solenoids PCS1 and PCS2 off electrically causes them to
be on hydraulically).
•
Return to Previous Range (RPR) Response
— When the speed sensor ratio or PS1 pressure switch tests associated with a shift are not successful,
the TCM commands the same range as commanded before the shift.
•
Neutral No Clutches (NNC) Response
— When certain speed sensor ratio or PS1 pressure switch tests are not successful, the TCM commands
a neutral condition with no clutches applied.
6–4.
SHIFT SELECTOR DISPLAYS RELATED TO ACTIVE CODES
•
“Cateye”—The forward slash segment and the middle horizontal segments (-/-) may be on under the
following conditions:
— Lost communication between the TCM and shift selector (U0103 or U0291)
— J1939 Controlled Area Network (CAN) problems
— Invalid data from shift selector (U0592 or U0404)
•
6–5.
All Segments Displayed—All display segments will be illuminated during shift selector initialization.
Low supply voltage can cause the shift selector to fail to complete initialization.
DIAGNOSTIC CODE LIST AND DESCRIPTION
Table 6–2. Diagnostic Troubleshooting Codes (DTC) and Descriptions
DTC
Description
CHECK
TRANS
Light
C1312 Retarder Request Sensor Failed Low
No
C1313 Retarder Request Sensor Failed High
No
P0122 Pedal Position Sensor Low Voltage
No
P0123 Pedal Position Sensor High Voltage
No
P0218 Transmission Fluid Over Temperature
No
P0602
P0610
P0613
P0614
Yes
Yes
No
Yes
TCM Not Programmed
TCM Vehicle Options (TransID) Error
TCM Processor
Torque Control Data Mismatch—ECM/TCM
P0634 TCM Internal Temperature Too High
P063E Auto Configuration Throttle Input Not Present
6–4
Yes
Yes
Copyright © 2005 General Motors Corp.
Inhibited Operation
Description
May inhibit retarder operation if not
using J1939 datalink
May inhibit retarder operation if not
using J1939 datalink
Use default throttle values. Freezes
shift adapts.
Use default throttle values. Freezes
shift adapts.
Use hot mode shift schedule. Holds
fourth range. TCC is inhibited.
Freezes shift adapts.
Lock in Neutral
Use TID A calibration
All solenoids off
Allows operation only in reverse and
second range.
SOL OFF (hydraulic default)
Use default throttle values
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
Table 6–2. Diagnostic Troubleshooting Codes (DTC) and Descriptions (cont’d)
DTC
Description
CHECK
TRANS
Light
Inhibited Operation
Description
P063F Auto Configuration Engine Coolant Temp Input Not
Present
P0658 Actuator Supply Voltage 1 (HSD1) Low
P0659 Actuator Supply Voltage 1 (HSD1) High
P0702 Transmission Control System Electrical (TransID)
P0703 Brake Switch Circuit Malfunction
No
None
Yes
Yes
Yes
No
P0708
P070C
P070D
P0711
Yes
No
No
Yes
DNS, SOL OFF (hydraulic default)
DNS, SOL OFF (hydraulic default)
Uses TID A calibration
No Neutral to Drive shifts for refuse
packer. TCM inhibits retarder
operation if a TPS code is also
active.
Ignore defective strip selector inputs
None
None
Use default sump temp
Yes
Use default sump temp
Yes
Use default sump temp
Yes
Yes
No
Yes
Yes
Yes
Yes
No
No
Yes
Yes
Yes
Yes
Yes
Yes
DNS, Lock in current range
DNS, Lock in current range
TCM assumes ABS is OFF
Inhibit RELS operation
None
DNS, Lock in current range
DNS, Lock in current range
Default to turbine speed
Default to turbine speed
DNS, Attempt 5th, then 3rd
DNS, Attempt 2nd, then 5th
DNS, Attempt 3rd, then 5th
DNS, Attempt 4th, then 6th
DNS, Attempt 5th, then 3rd
DNS, Attempt 6th, then 3rd,
then 2nd
DNS, Lock in Neutral
None
DNS, RPR
DNS, RPR
P0716
P0717
P0719
P071A
P071D
P0721
P0722
P0726
P0727
P0729
P0731
P0732
P0733
P0734
P0735
Transmission Range Sensor Circuit High Input
Transmission Fluid Level Sensor Circuit—Low Input
Transmission Fluid Level Sensor Circuit—High Input
Transmission Fluid Temperature Sensor Circuit
Performance
Transmission Fluid Temperature Sensor Circuit
Low Input
Transmission Fluid Temperature Sensor Circuit
High Input
Turbine Speed Sensor Circuit Performance
Turbine Speed Sensor Circuit No Signal
Brake Switch ABS Input Low
RELS Input Failed On
General Purpose Input Fault
Output Speed Sensor Circuit Performance
Output Speed Sensor Circuit No Signal
Engine Speed Sensor Circuit Performance
Engine Speed Sensor Circuit No Signal
Incorrect 6th Gear Ratio
Incorrect 1st Gear Ratio
Incorrect 2nd Gear Ratio
Incorrect 3rd Gear Ratio
Incorrect 4th Gear Ratio
Incorrect 5th Gear Ratio
P0736
P0741
P0776
P0777
Incorrect Reverse Gear Ratio
Torque Converter Clutch System Stuck Off
Pressure Control Solenoid 2 Stuck Off
Pressure Control Solenoid 2 Stuck On
P0712
P0713
Yes
Yes
Yes
Yes
Copyright © 2005 General Motors Corp.
6–5
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
Table 6–2. Diagnostic Troubleshooting Codes (DTC) and Descriptions (cont’d)
DTC
Description
P0796
P0797
P0842
P0843
P0880
P0881
P0882
P0883
P0894
P0960
P0973
P0974
P0975
P0976
Pressure Control Solenoid 3 Stuck Off
Pressure Control Solenoid 3 Stuck On
Transmission Pressure Switch 1 Circuit Low
Transmission Pressure Switch 1 Circuit High
TCM Power Input Signal
TCM Power Input Signal Performance
TCM Power Input Signal Low
TCM Power Input Signal High
Transmission Component Slipping
Pressure Control Solenoid Main Mod Control
Circuit Open
Pressure Control Solenoid Main Mod Control
Circuit Low
Pressure Control Solenoid Main Mod Control
Circuit High
Pressure Control Solenoid 2 (PCS2) Control
Circuit Open
Pressure Control Solenoid 2 (PCS2) Control Circuit Low
Pressure Control Solenoid 2 (PCS2) Control
Circuit High
Pressure Control Solenoid 3 (PCS3) Control
Circuit Open
Pressure Control Solenoid 3 (PCS3) Control Circuit Low
Pressure Control Solenoid 3 (PCS3) Control
Circuit High
Shift Solenoid 1 (SS1) Control Circuit Low
Shift Solenoid 1 (SS1) Control Circuit High
Shift Solenoid 2 (SS2) Control Circuit Open
Shift Solenoid 2 (SS2) Control Circuit Low
P0977
P0989
P0990
P1739
Shift Solenoid 2 (SS2) Control Circuit High
Retarder Pressure Sensor Failed Low
Retarder Pressure Sensor Failed High
Incorrect Low Gear Ratio
P0962
P0963
P0964
P0966
P0967
P0968
P0970
P0971
P1891 Throttle Position Sensor PWM Signal Low Input
P1892 Throttle Position Sensor PWM Signal High Input
P2184 Engine Coolant Temperature Sensor Circuit Low Input
6–6
CHECK
TRANS
Light
Inhibited Operation
Description
Yes
Yes
Yes
Yes
No
No
Yes
No
Yes
Yes
DNS, RPR
DNS, RPR
DNS, Lock in current range
DNS, Lock in current range
None
None
DNS, SOL OFF (hydraulic default)
None
DNS, Lock in first
None
Yes
DNS, SOL OFF (hydraulic default)
Yes
None
Yes
DNS, SOL OFF (hydraulic default)
Yes
Yes
DNS, SOL OFF (hydraulic default)
DNS, SOL OFF (hydraulic default)
Yes
DNS, SOL OFF (hydraulic default)
Yes
Yes
DNS, SOL OFF (hydraulic default)
DNS, SOL OFF (hydraulic default)
Yes
Yes
Yes
Yes
DNS, SOL OFF (hydraulic default)
DNS, SOL OFF (hydraulic default)
7-speed: Allow 2 through 6, N, R
7-speed: Allow 2 through 6, N, R.
Inhibit TCC operation
7-speed: Allow 2 through 6, N, R
None
None
Command 2nd and allow shifts 2
through 6, N, R
Use default throttle values
Use default throttle values
Use default engine coolant values
Yes
No
No
Yes
No
No
No
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
Table 6–2. Diagnostic Troubleshooting Codes (DTC) and Descriptions (cont’d)
DTC
Description
P2185 Engine Coolant Temperature Sensor Circuit
High Input
P2637 Torque Management Feedback Signal (SEM)
P2641 Torque Management Feedback Signal (LRTP)
P2670 Actuator Supply Voltage 2 (HSD2) Low
P2671 Actuator Supply Voltage 2 (HSD2) High
P2685 Actuator Supply Voltage 3 (HSD3) Low
P2686 Actuator Supply Voltage 3 (HSD3) High
P2714 Pressure Control Solenoid 4 (PCS4) Stuck Off
P2715 Pressure Control Solenoid 4 (PCS4) Stuck On
P2718 Pressure Control Solenoid 4 (PCS4) Control
Circuit Open
P2720 Pressure Control Solenoid 4 (PCS4) Control Circuit Low
P2721 Pressure Control Solenoid 4 (PCS4) Control
Circuit High
P2723 Pressure Control Solenoid 1 (PCS1) Stuck Off
P2724 Pressure Control Solenoid 1 (PCS1) Stuck On
P2727 Pressure Control Solenoid 1 (PCS1) Control
Circuit Open
P2729 Pressure Control Solenoid 1 (PCS1) Control Circuit Low
P2730 Pressure Control Solenoid 1 (PCS1) Control
Circuit High
P2736 Pressure Control Solenoid 5 (PCS5) Control
Circuit Open
P2738 Pressure Control Solenoid 5 (PCS5) Control Circuit Low
CHECK
TRANS
Light
Inhibited Operation
Description
No
Use default engine coolant values
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Inhibit SEM
Inhibit LRTP
DNS, SOL OFF (hydraulic default)
DNS, SOL OFF (hydraulic default)
DNS, SOL OFF (hydraulic default)
DNS, SOL OFF (hydraulic default)
DNS, RPR
DNS, SOL OFF (hydraulic default)
DNS, SOL OFF (hydraulic default)
Yes
Yes
DNS, SOL OFF (hydraulic default)
DNS, SOL OFF (hydraulic default)
Yes
Yes
Yes
DNS, RPR
DNS, RPR
DNS, SOL OFF (hydraulic default)
Yes
Yes
DNS, SOL OFF (hydraulic default)
DNS, SOL OFF (hydraulic default)
Yes
Inhibit retarder operation
Yes
Allow 2 through 6, N, R. Inhibit
retarder and TCC operation
Inhibit retarder operation
P2739 Pressure Control Solenoid 5 (PCS5) Control
Circuit High
P2740 Retarder Oil Temperature Hot
P2742 Retarder Oil Temperature Sensor Circuit—Low Input
P2743 Retarder Oil Temperature Sensor Circuit—High Input
P2761 TCC PCS Control Circuit Open
P2763 TCC PCS Control Circuit High
P2764 TCC PCS Control Circuit Low
Yes
No
No
No
Yes
Yes
Yes
P278A Kickdown Input Failed ON
P2793 Gear Shift Direction Circuit
No
Yes
P2808 Pressure Control Solenoid 6 (PCS6) Stuck Off
Yes
Copyright © 2005 General Motors Corp.
None
Use default retarder temp values
Use default retarder temp values
Inhibit TCC operation
Inhibit TCC operation
7-speed: allow 2 through 6, N, R.
Inhibit TCC operation
Inhibit kickdown operation
Ignores PWM input from shift
selector
DNS, RPR
6–7
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
Table 6–2. Diagnostic Troubleshooting Codes (DTC) and Descriptions (cont’d)
DTC
Description
P2809 Pressure Control Solenoid 6 (PCS6) Stuck On
P2812 Pressure Control Solenoid 6 (PCS6) Control
Circuit Open
P2814 Pressure Control Solenoid 6 (PCS6) Control Circuit Low
P2815 Pressure Control Solenoid 6 (PCS6) Control
Circuit High
U0001 Hi Speed CAN Bus Reset Counter Overrun (IESCAN)
U0010 CAN BUS Reset Counter Overrun
U0100 Lost Communications with ECM/PCM (J1587)
U0103 Lost Communication With Gear Shift Module
(Shift Selector) 1
U0115 Lost Communication With ECM
U0291 Lost Communication With Gear Shift Module
(Shift Selector) 2
U0304 Incompatible Gear Shift Module 1 (Shift Selector) ID
U0333 Incompatible Gear Shift Module 2 (Shift Selector) ID
U0404 Invalid Data Received From Gear Shift Module
(Shift Selector) 1
U0592 Invalid Data Received From Gear Shift Module
(Shift Selector) 2
6–8
CHECK
TRANS
Light
Inhibited Operation
Description
Yes
Yes
DNS, RPR
DNS, SOL OFF (hydraulic default)
Yes
Yes
DNS, SOL OFF (hydraulic default)
DNS, SOL OFF (hydraulic default)
No
No
Yes
Yes
Use default values, inhibit SEM
Use default values, inhibit SEM
Use default values
Maintain range selected, observe
gear shift direction circuit
Use default values
Maintain range selected, observe
gear shift direction circuit
Ignore shift selector inputs
Ignore shift selector inputs
Maintain range selected, observe
gear shift direction circuit
Maintain range selected, observe
gear shift direction circuit
Yes
Yes
Yes
Yes
Yes
Yes
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
TRANSMISSION
COMPONENT
WIRING DIAGRAMS
AND
DIAGNOSTICS
Copyright © 2005 General Motors Corp.
6–9
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
NOTES
6–10
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
J 39700 BREAKOUT BOX
J 47275-1
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
Detail of
TCM Overlay
for use with
J 47275
TCM Breakout
Harness Adapter
16-Pin Bypass
Connector
80-Way Connector
To Vehicle
80-Way Connector
To TCM
TCM
V09225.01.00
Figure 6–1. J 39700 Breakout Box and J 47275 TCM Breakout Harness Adapter
Copyright © 2005 General Motors Corp.
6–11
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
J 39700 BREAKOUT BOX
J 47279-1
A
B
A
B
1
2
9
10
A
B
TURBINE SPEED
SENSOR
ENGINE SPEED
SENSOR
A
WT RETARDER
AIR SOLENOID
B
4
5
B
A
B
6
7
8
15
16
RETARDER FEED
THRU VALVE BODY
RETARDER TEMP
3
A
OUTPUT SPEED
SENSOR
11
12
13
14
17
18
19
20
Detail of
Magnetic Overlay
for use with
J 47279
Transmission
Breakout Harness
To Existing
Harness
To Engine
Speed Sensor
To Existing *
Harness
To Turbine *
Speed Sensor
To Existing
Harness
To Existing
Harness
To Output
Speed Sensor
To Retarder
Solenoid
To Existing
Harness
To Existing
Harness
To Retarder
Air Solenoid
*NOTE: 4000 Product Family
To Existing
Harness
To Retarder
Temperature Sensor
To Transmission
Connector
V09224.00.00
Figure 6–2. J 39700 Breakout Box and J 47279 Transmission Breakout Harness
6–12
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
J1939-13 9-Pin
Deutsch Connector
J1962 Connector
To GM LAN
(GM Pickup Truck
Application)
24-Way Connector
To Vehicle
80-Way Connector
To TCM
TCM
V09227.00.00
Figure 6–3. J 47276 “T” Breakout and TCM Reflashing Harness
Copyright © 2005 General Motors Corp.
6–13
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
6–6.
DIAGNOSTIC CODE TROUBLESHOOTING
A.
Beginning The Troubleshooting Process
1. Begin troubleshooting by determining the transmission fluid level and TCM input voltage. Access
diagnostic codes by using:
• The shift selector display.
• Allison DOC™ For PC–Service Tool.
2. When a problem exists but a diagnostic code is not indicated, refer to Section 8, General Troubleshooting of Performance Complaints for a listing of various electrical and hydraulic problems, their
causes, and remedies.
3. If a diagnostic code is found in the TCM memory, record all available code information and clear
the active indicator. Read TCM freeze frame data using Allison DOC™ For PC–Service Tool. Refer to Section 6–2.
4. Test drive the vehicle to confirm a diagnostic code or performance complaint.
• If the code reappears, refer to Section 6–5, Table 6–2. Table 6–2 lists diagnostic codes and their
description.
• If the code does not reappear, it may be an intermittent problem. Use Allison DOC™ For PC–
Service Tool or the code display procedure described in Section 6–2.
• The code display procedure will indicate the number of times the diagnostic code has occurred.
Refer to Section 8, General Troubleshooting of Performance Complaints, for the possible
cause(s) of the problem.
• Use pressure gauges as necessary to evaluate hydraulic conditions.
• Appendix A deals with the identification of potential circuit problems. Refer to Appendix A if a
circuit problem is suspected.
5. If difficulties arise, you have unanswered questions, or if you are unable to quickly identify the root
cause during troubleshooting, please contact the Technical Assistance Center (TAC):
Technical Assistance Center
PO Box 894, Mail Code 462-470-PF9
Indianapolis, IN 46206-0894
Phone: 1-800-252-5283
NOTE:
Information concerning specific items is contained in the appendices located in the back of this
manual. The appendices are referred to throughout the manual.
B.
Solenoid Locations
Solenoid locations in the control module are as illustrated in Figure 6–3. Refer to Figure 6–3 as
necessary when using the diagnostic code schematics.
C.
Diagnostic Code Schematics
The diagnostic code schematics in this section show wiring for both the optional oil level sensor and
retarder, where applicable. If your transmission is not equipped with an oil level sensor or retarder,
disregard the portions of the schematic pertaining to those optional pieces of equipment. Refer to the
appropriate transmission service manual for solenoid replacement procedures.
6–14
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
LEFT
FRONT
RIGHT
NT (TURBINE SPEED SENSOR
3000 PRODUCT FAMILIES ONLY)
PCS6 (C6)
(3000 AND 4000
PRODUCT FAMILIES –
7-SPEED MODELS ONLY)
PS1 PRESSURE SWITCH
TCC LOCKUP
PCS1 (C1)
MAIN MOD
PCS4 (C4)
PCS3 (C3/C5)
PCS2 (C2/C3)
SS1 (FORWARD–ON
MAIN VALVE BODY)
SS2 (C6 ENABLE)
(3000 AND 4000 PRODUCT FAMILIES
7-SPEED MODELS ONLY)
BACK
V09250.00.00
Figure 6–4. Control Module Solenoid Location
Copyright © 2005 General Motors Corp.
6–15
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC C1312 Retarder Request Sensor Failed Low
END VIEW OF
20-WAY CONNECTOR
END VIEW OF
80-WAY CONNECTOR
1
6
7
10
11
14
15
20
61
80
41
60
21
40
1
20
TO RETARDER
CONTROL DEVICES
RETARDER
REQUEST SENSOR
(RESISTANCE
MODULE)
A
PWM
THROTTLE
SOURCE
B
C
TCM
THROTTLE
POSITION
SENSOR (TPS)
OR
ELECTRONIC
BRAKING (EBS)
RTDR PRESSURE
SENSOR
WIRE 156
WIRE 112
C
WIRE 144
B
WIRE 158
A
RETARDER TEMP
ENGINE TEMP
WIRE 175
WIRE 135
TRANSMISSION
ANALOG RETURN
OIL LEVEL
HALL
A
C
EFFECT
B
SUMP TEMP
19
16
15
18
PS1
NC*
* NORMALLY
3
56
RETARDER REQUEST SIGNAL
12
5V SENSOR VOLTAGE
44
THROTTLE POSITION OR
RTDR PRESSURE SIGNAL
58
ANALOG RETURN
75
RETARDER TEMP
35
ENGINE WATER TEMP
16
OIL LEVEL SENSOR
54
SUMP TEMP
77
PS1 DIAGNOSTIC
PRESSURE SWITCH
WIRE 158
WIRE 112
WIRE 116
WIRE 154
WIRE 177
CLOSED
V09069.01.00
6–16
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC C1312 Retarder Request Sensor Failed Low
Circuit Description
The Transmission Control Module (TCM) can be calibrated to receive a retarder request signal from a retarder
request sensor, sometimes called a resistance module. The TCM is connected to the retarder request sensor by:
•
a reference voltage wire,
•
retarder request signal wire, and
•
analog ground wire.
The TCM provides a 5V reference voltage to the retarder request sensor. A voltage divider network in the sensor
produces a retarder request signal in response to inputs from the retarder control device(s). The TCM interprets this
signal as a percent retarder requested.
Conditions for Running the DTC
•
The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater
than 9V and less than 32V (24V TCM).
•
The components are powered and engine speed is greater than 200 rpm and less than 7500 rpm.
Conditions for Setting the DTC
DTC C1312 sets if the TCM is calibrated to receive the retarder request signal, and the signal voltage is less than
0.3V for five seconds.
Actions Taken When the DTC Sets
When DTC C1312 is active, the following conditions will occur:
•
The TCM does not illuminate the CHECK TRANS light.
•
DTC is stored in TCM history.
•
TCM may inhibit retarder operation, if not using the J1939 Datalink for retarder request signal.
Conditions for Clearing DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
•
DTC C1312 indicates the TCM has detected a voltage signal from the retarder request sensor in the low error
zone. The code can be caused by:
— Faulty wiring.
— Faulty connections to the retarder request sensor or retarder control device.
— A faulty retarder request sensor (resistance module).
— A faulty retarder control device.
— A faulty TCM.
•
DTC C1312 can be caused by an open or short-to-ground in either the 5V reference wire 112 or retarder
request signal wire 156. The retarder request sensor shares a common 5V reference voltage with the
transmission oil level sensor (OLS) and throttle position sensor (TPS) on wire 112. An open or short-to-ground
in the common 5V reference causes a “sensor failed low” code for the other devices as well. An open or shortto-ground on wire 156 will cause a DTC C1312 only.
Copyright © 2005 General Motors Corp.
6–17
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
•
Inspect the wiring for poor electrical connections at the TCM. Look for the following conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
Test Description
This DTC requires the use of the J 47275 TCM Breakout. The numbers below refer to step numbers on the
diagnostic table.
2.
3.
5.
6.
This step tests for an active DTC.
This step tests for defective wiring in external harness.
This step tests for retarder request sensor functionality.
This step tests for proper 5V reference voltage at the TCM with OEM harness disconnected.
DTC C1312 Retarder Request Sensor Failed Low
Step
1
2
3
6–18
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
1.
2.
3.
4.
Install the Allison DOC™ For PC–Service Tool.
Start the engine.
Record the failure records.
Clear the DTC and drive the vehicle. Attempt to
duplicate same operating conditions observed in
failure records.
NOTE: This DTC indicates that the retarder
request sensor voltage is below a set voltage for a set
period of time. It may also indicate an open or
short-to-ground in either the 5V reference wire 112
or retarder request signal wire 156.
Did DTC C1312 return?
1. Turn OFF the ignition.
2. Inspect the routing of 5V reference wire 112,
retarder request signal wire 156, and analog
return (ground) wire 158 between the TCM and
the retarder request sensor.
3. Disconnect the 80-way connector from the TCM.
4. Install the OEM-side of the 80-way connector to
J 47275 TCM Breakout. Leave the TCM
disconnected.
5. Disconnect the transmission 20-way connector,
RMR connector, and TPS connector, if installed.
6. Test for opens or shorts-to-ground on wires 112
and 156.
Was chafing or wire damage found?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 2
Go to Step 3
Go to Step 4
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Go to
Diagnostic Aids
Go to Step 5
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC C1312 Retarder Request Sensor Failed Low (cont’d)
Step
4
5
6
7
8
9
10
Action
NOTE: The vehicle OEM has responsibility for all
external wiring harness repairs. Harness repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Coordinate with the vehicle OEM to repair or
replace the vehicle wiring.
Is the repair complete?
1. Turn OFF the ignition.
2. Reconnect the TCM to J 47275 TCM Breakout.
3. Reconnect the RMR connector, transmission
20-way connector, and TPS connector, if
installed.
4. Turn ON the ignition.
5. At J 47275-1 TCM overlay, connect a DVOM and
measure voltage between pins 56 and 58 for each
position of each retarder control device used on
the vehicle.
If two resistance modules are used, disconnect one
of them when measuring voltage signals from the
other.
Are the voltages within the specified values?
1. Turn OFF the ignition.
2. Disconnect the 16-pin bypass connector on
J 47275 TCM Breakout.
3. Turn ON the ignition.
4. At J 47275-1 TCM Overlay, connect a DVOM
and measure voltage between pins 12 and 58.
Is the voltage within the specified value?
Replace the retarder request sensor (resistance
module).
Is replacement complete?
After replacing the retarder request sensor, perform
the following:
1. Turn ON the ignition.
2. Reconnect the 16-pin bypass connector on
J 47275 TCM Breakout.
3. At J 47275-1 TCM overlay, connect a DVOM and
measure voltage between pins 56 and 58 for each
position of each retarder control device used on
the vehicle.
If two resistance modules are used, disconnect one
of them when measuring voltage signals from the
other.
Are voltages within specified values?
Replace the retarder control device.
Is replacement complete?
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
Refer to TCM diagnostic procedure, Section 3–6.
Is Section 3–6 complete?
Value(s)
Yes
Go to Step 11
No
Refer to
Table 6–3
Go to Step 10
Go to Step 6
4.75–5.0V
Go to Step 7
Go to Step 10
Go to Step 8
Refer to
Table 6–3
Copyright © 2005 General Motors Corp.
Go to Step 11
Go to Step 9
Go to Step 11
Go to Step 11
6–19
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC C1312 Retarder Request Sensor Failed Low (cont’d)
Step
11
Action
In order to verify your repair:
1. Clear the DTC.
2. Use Allison DOC™ For PC–Service Tool to
monitor retarder request signal.
3. Drive the vehicle under conditions noted in
failure records.
4. Confirm with the service tool in the test passed
section that the diagnostic test was run.
Did the DTC return?
Value(s)
Yes
Begin the
diagnosis again.
Go to Step 1
No
System OK
Table 6–3. Voltage/Resistance
Description
Auto Full On
Pressure Switch
Full On
High
3-Step E-10R
Bendix Pedal
6-Step Hand Lever
OFF
Position 1
Position 2
Position 3
Position 4
Position 5
Position 6
Auto 1/2 ON
3 Pressure Switches
Low
Medium
High
Auto 1/2 ON
2 Pressure Switches
Auto
Medium
High
Dedicated Pedal
Resistance Test in
Resistance Module*
Resistance
Ω +/− 5%
KΩ
Terminals
A to C
12
A to C
32
A to C
32
A to C
32
A to C
A to C
12
32
A to C
Voltage Signal**
Voltage
% Retarder
+/− 0.2V
Application
100
3.6
Device Terminal
No connections
0
100
0
32
58
100
1.1
3.6
1.1
1.9
2.8
3.6
A
B
A
B
C
D
0
14
28
45
65
82
100
50
0
32
68
100
1.1
1.5
1.9
2.3
2.8
3.2
3.6
2.4
1.1
1.9
2.8
3.6
+
1
2
3
4
5
6
No connections
32
68
100
0
100
1.9
2.8
3.6
0.7–1.2
3.4–3.5
A
B
A and B
A
B
C
A and B
A and B
A and B
21.4
No Check
Interface not a
resistance module
* Resistance module must be disconnected from the wiring harness and retarder control devices.
** These voltages may be measured between TCM pins 56 and 58 using J 47275 TCM Breakout.
6–20
Wiring to Control
Device
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC C1313 Retarder Request Sensor Failed High
END VIEW OF
20-WAY CONNECTOR
END VIEW OF
80-WAY CONNECTOR
1
6
7
10
11
14
15
20
61
80
41
60
21
40
1
20
TO RETARDER
CONTROL DEVICES
RETARDER
REQUEST SENSOR
(RESISTANCE
MODULE)
A
PWM
THROTTLE
SOURCE
B
C
TCM
THROTTLE
POSITION
SENSOR (TPS)
OR
ELECTRONIC
BRAKING (EBS)
RTDR PRESSURE
SENSOR
WIRE 156
WIRE 112
C
WIRE 144
B
WIRE 158
A
RETARDER TEMP
ENGINE TEMP
WIRE 175
WIRE 135
TRANSMISSION
ANALOG RETURN
OIL LEVEL
HALL
A
C
EFFECT
B
SUMP TEMP
19
16
15
18
PS1
NC*
* NORMALLY
3
56
RETARDER REQUEST SIGNAL
12
5V SENSOR VOLTAGE
44
THROTTLE POSITION OR
RTDR PRESSURE SIGNAL
58
ANALOG RETURN
75
RETARDER TEMP
35
ENGINE WATER TEMP
16
OIL LEVEL SENSOR
54
SUMP TEMP
77
PS1 DIAGNOSTIC
PRESSURE SWITCH
WIRE 158
WIRE 112
WIRE 116
WIRE 154
WIRE 177
CLOSED
V09069.01.00
Copyright © 2005 General Motors Corp.
6–21
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC C1313 Retarder Request Sensor Failed High
Circuit Description
The Transmission Control Module (TCM) can be calibrated to receive a retarder request signal from a retarder
request sensor, sometimes called a resistance module. The TCM is connected to the retarder request sensor by:
•
a reference voltage wire,
•
retarder request signal wire, and
•
analog ground wire.
The TCM provides a 5V reference voltage to the retarder request sensor. A voltage divider network in the sensor
produces a retarder request signal in response to inputs from the retarder control device(s). The TCM interprets this
signal as a percent retarder requested.
Conditions for Running the DTC
•
The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater
than 9V and less than 32V (24V TCM).
•
The components are powered and engine speed is greater than 200 rpm and less than 7500 rpm.
Conditions for Setting the DTC
DTC C1313 sets if the TCM is calibrated to receive the retarder request signal, and the signal voltage is greater
than 4.7V for 5 seconds.
Actions Taken When the DTC Sets
When DTC C1313 is active, the following conditions will occur:
•
The TCM does not illuminate the CHECK TRANS light.
•
DTC is stored in TCM history.
•
TCM may inhibit retarder operation, if not using the J1939 Datalink for retarder request signal.
Conditions for Clearing DTC/CHECK TRANS Light
The Allison DOC For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
•
DTC C1313 indicates the TCM has detected a voltage signal from the retarder request sensor in the high error
zone. The code can be caused by:
— Faulty wiring.
— Faulty connections to the retarder request sensor or retarder control device.
— A faulty retarder request sensor (resistance module).
— A faulty retarder control device.
— A faulty TCM.
•
DTC C1313 can be caused by a short-to-battery in the 5V reference wire 112 or retarder request signal
wire 156. DTC C1313 can also be caused by an open in analog return wire 158. The retarder request sensor
shares a common 5V reference voltage with the transmission oil level sensor (OLS) and throttle position sensor
(TPS) on wire 112. A short-to-battery in the 5V reference wire 112 or open in analog return wire 158 causes a
“sensor failed high” code for the other devices as well. A short-to-battery in retarder request signal wire 156
will produce a DTC C1313 only.
6–22
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
•
Inspect the wiring for poor electrical connections at the TCM. Look for the following conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
Test Description
This DTC requires the use of the J 47275 TCM Breakout. The numbers below refer to step numbers on the
diagnostic table.
2. This step tests for an active DTC.
3. This step tests for defective wiring in external harness.
5. This step tests for retarder request sensor functionality.
6. This step tests for proper 5V reference voltage at the TCM with OEM harness disconnected.
DTC C1313 Retarder Request Sensor Failed High
Step
1
2
3
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
1.
2.
3.
4.
Install the Allison DOC™ For PC–Service Tool.
Start the engine.
Record the failure records.
Clear the DTC and drive the vehicle. Attempt to
duplicate same operating conditions observed in
failure records.
NOTE: This DTC indicates that the retarder
request sensor voltage is above a set voltage for a set
period of time. It may also indicate a short-tobattery on 5V reference wire 112 or an open on
analog return wire 158.
Did DTC C1313 return?
1. Turn OFF the ignition.
2. Inspect the routing of 5V reference wire 112,
retarder request signal wire 156, and analog
return (ground) wire 158 between the TCM and
the retarder request sensor.
3. Disconnect the 80-way connector from the TCM.
4. Install the OEM-side of the 80-way connector to
the J 47275 TCM Breakout. Leave the TCM
disconnected.
5. Disconnect the transmission 20-way connector,
RMR connector, and TPS connector, if installed.
6. Test for shorts-to-battery on wires 112 and 156,
and opens on wire 158.
Was chafing or wire damage found?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 2
Go to Step 3
Go to Step 4
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Go to
Diagnostic Aids
Go to Step 5
6–23
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC C1313 Retarder Request Sensor Failed High (cont’d)
Step
4
5
6
7
8
9
10
6–24
Action
NOTE: The vehicle OEM has responsibility for all
external wiring harness repairs. Harness repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Coordinate with the vehicle OEM to repair or
replace the vehicle wiring.
Is the repair complete?
1. Turn OFF the ignition.
2. Reconnect the TCM to J 47275 TCM Breakout.
3. Reconnect the RMR connector, transmission
20-way connector, and TPS connector, if
installed.
4. Turn ON the ignition.
5. At J 47275-1 TCM Overlay, connect a DVOM
and measure voltage between pins 56 and 58 for
each position of each retarder control device used
on the vehicle.
If two resistance modules are used, disconnect one of
them when measuring voltage signals from the other.
Are the voltages within the specified values?
1. Turn OFF the ignition.
2. Disconnect the 16-pin bypass connector on
J 47275 TCM Breakout.
3. Turn ON the ignition.
4. At J 47275-1 TCM Overlay, connect a DVOM
and measure voltage between pins 12 and 58.
Is the voltage within the specified value?
Replace the retarder request sensor (resistance
module).
Is replacement complete?
After replacing the retarder request sensor, perform
the following:
1. Turn ON the ignition.
2. Reconnect the 16-pin bypass connector on
J 47275 TCM Breakout.
3. At J 47275-1 TCM Overlay, connect a DVOM
and measure voltage between pins 56 and 58 for
each position of each retarder control device used
on the vehicle.
If two resistance modules are used, disconnect one of
them when measuring voltage signals from the other.
Are voltages within specified values?
Replace the retarder control device.
Is replacement complete?
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
Refer to TCM diagnostic procedure, Section 3–6.
Is Section 3–6 complete?
Value(s)
Yes
Go to Step 11
No
Refer to
Table 6–4
Go to Step 10
Go to Step 6
4.7–5.0V
Go to Step 7
Go to Step 10
Go to Step 8
Refer to
Table 6–4
Copyright © 2005 General Motors Corp.
Go to Step 11
Go to Step 11
Go to Step 11
Go to Step 9
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC C1313 Retarder Request Sensor Failed High (cont’d)
Step
11
Action
In order to verify your repair:
1. Clear the DTC.
2. Use Allison DOC™ For PC–Service Tool to
monitor retarder request signal.
3. Drive the vehicle under conditions noted in
failure records.
4. Confirm with the service tool in the test passed
section that the diagnostic test was run.
Did the DTC return?
Value(s)
Yes
Begin the
diagnosis again.
Go to Step 1
No
System OK
Table 6–4. Voltage/Resistance
Description
Auto Full On
Pressure Switch
Full On
High
3-Step E-10R
Bendix Pedal
6-Step Hand Lever
OFF
Position 1
Position 2
Position 3
Position 4
Position 5
Position 6
Auto 1/2 ON
3 Pressure Switches
Low
Medium
High
Auto 1/2 ON
2 Pressure Switches
Auto
Medium
High
Dedicated Pedal
Resistance Test in
Resistance Module*
Resistance
Ω +/− 5%
KΩ
Terminals
A to C
12
A to C
32
A to C
32
A to C
32
A to C
A to C
12
32
A to C
Voltage Signal**
Voltage
% Retarder
+/− 0.2V
Application
100
3.6
Wiring to Control
Device
Device Terminal
No connections
0
100
0
32
58
100
1.1
3.6
1.1
1.9
2.8
3.6
A
B
A
B
C
D
0
14
28
45
65
82
100
50
0
32
68
100
1.1
1.5
1.9
2.3
2.8
3.2
3.6
2.4
1.1
1.9
2.8
3.6
+
1
2
3
4
5
6
No connections
32
68
100
0
100
1.9
2.8
3.6
0.7–1.2
3.4–3.5
A
B
A and B
A
B
C
A and B
A and B
A and B
21.4
No Check
Interface not a
resistance module
* Resistance module must be disconnected from the wiring harness and retarder control devices.
** These voltages may be measured between TCM pins 56 and 58 using J 47275 TCM Breakout.
Copyright © 2005 General Motors Corp.
6–25
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0122 Pedal Position Sensor Low Voltage
END VIEW OF
20-WAY CONNECTOR
END VIEW OF
80-WAY CONNECTOR
1
6
7
10
11
14
15
20
61
80
41
60
21
40
1
20
TO RETARDER
CONTROL DEVICES
RETARDER
REQUEST SENSOR
(RESISTANCE
MODULE)
A
PWM
THROTTLE
SOURCE
B
C
TCM
THROTTLE
POSITION
SENSOR (TPS)
OR
ELECTRONIC
BRAKING (EBS)
RTDR PRESSURE
SENSOR
WIRE 156
WIRE 112
C
WIRE 144
B
WIRE 158
A
RETARDER TEMP
ENGINE TEMP
TRANSMISSION
ANALOG RETURN
OIL LEVEL
HALL
A
C
EFFECT
B
SUMP TEMP
19
16
15
18
PS1
NC*
* NORMALLY
3
WIRE 175
WIRE 135
56
RETARDER REQUEST SIGNAL
12
5V SENSOR VOLTAGE
44
THROTTLE POSITION OR
RTDR PRESSURE SIGNAL
58
ANALOG RETURN
75
RETARDER TEMP
35
ENGINE WATER TEMP
16
OIL LEVEL SENSOR
54
SUMP TEMP
77
PS1 DIAGNOSTIC
PRESSURE SWITCH
WIRE 158
WIRE 112
WIRE 116
WIRE 154
WIRE 177
CLOSED
V09069.01.00
6–26
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0122 Pedal Position Sensor Low Voltage
Circuit Description
The Transmission Control Module (TCM) may receive input on throttle position from either a Throttle Position
Sensor (TPS) or a signal transmitted by the engine electronic controls.
Vehicles not equipped with electronically-controlled engines have a TPS attached to the engine fuel control
linkage. The TPS continuously sends the exact throttle position to the transmission TCM.
The TPS is a sliding resistor sensor (potentiometer) actuated by a mechanical linkage. The TCM delivers a constant
voltage to one terminal of the TPS resistive strip. The other TPS terminal connects to ground. The resistor contacts
of the TPS provide a regulated voltage signal input to the TCM.
When actuated by the mechanical throttle cable, the contacts of the resistor move along the resistive strip. As the
contacts slide along the resistive strip, a voltage is sent to the TCM. At each increment of 0.78 mm (0.007 inch)
along the resistive strip, the contacts deliver a different voltage to the TCM. The different voltages are interpreted
as throttle sensor movement. The TCM converts travel distance (mm) into throttle opening percentage.
Conditions for Running the DTC
• The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater
than 9V and less than 32V (24V TCM).
•
The components are powered and engine speed is greater than 200 rpm.
•
DTC P0122 Pedal Position Sensor Circuit High Voltage is not active.
Conditions for Setting the DTC
DTC P0122 sets when the TCM detects a throttle position sensor voltage less than 0.55V for 5 seconds.
Action Taken When the DTC Sets
• The TCM does not illuminate the CHECK TRANS light.
•
DTC P0122 is stored in the TCM memory.
•
The TCM uses the default throttle value, based on engine torque and speed.
•
The TCM freezes shift adapts (DNA).
Conditions for Clearing the DTC/CHECK TRANS LIGHT
The Allison DOC™ For PC–Service Tool may be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without the DTC
recurring.
Diagnostic Aids
• Inspect the wiring for poor electrical connections at the TCM. Look for the following conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
• When diagnosing for an intermittent short or open, massage the wiring harness while watching the test
equipment for a change.
•
You may have to drive the vehicle in order to experience a fault.
Copyright © 2005 General Motors Corp.
6–27
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
•
DTC P0122 can be caused by an open or short-to-ground in either the 5V reference wire 112 or TPS signal
wire 144. The TPS shares a common 5V reference voltage wire 112 with the optional transmission oil level
sensor (OLS) and retarder request sensor. An open or short-to-ground in the common 5V reference causes a
“sensor failed low” code for the other devices as well. An open or short-to-ground on wire 144 will cause a
DTC P0122 only.
Test Description
This DTC requires the use of the J 47275 TCM Breakout. The numbers below refer to step numbers on the
diagnostic table.
2. This step tests for the proper adjustment of TPS.
3. This step tests for the proper ignition voltage.
4. This step tests for the proper TCM 5V reference voltage.
5. This step tests for dead spots in the potentiometer.
6. This step tests for abnormal TPS resistance.
7. This step tests for proper resistance of the TPS circuit.
8. This step tests for an open or short-to-ground in TPS signal wire 144.
9. This step tests for proper 5V reference voltage at TCM without OEM harness.
10. This step tests for an open or short-to-ground on 5V reference wire 112.
DTC P0122 Pedal Position Sensor Low Voltage
Step
1
2
3
4
6–28
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
Refer to Appendix F to check for proper TPS
adjustment.
Is the TPS adjusted properly?
1. Install the Allison DOC™ For PC–Service Tool. 9−18V (12V TCM)
18−32V (24V TCM)
2. Start the engine.
3. Record the DTC failure record data.
4. Using the Allison DOC™ For PC–Service Tool,
measure ignition voltage.
Is voltage within the specified values?
1. Turn OFF the ignition.
4.75−5.0V
2. Disconnect the 80-way connector from the TCM
and install the J 47275 TCM Breakout between
the TCM and the OEM-side connector.
3. With the engine OFF, turn the ignition to the ON
position.
4. Using a DVOM, measure the voltage between
pins 12 and 58.
Is the voltage within the specified value?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 2
Go to Step 3
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Adjust TPS to
proper setting.
Go to Step 12
Go to Step 4
Resolve voltage
problem (refer to
DTC P0882 and
DTC P0883)
Go to Step 5
Go to Step 9
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0122 Pedal Position Sensor Low Voltage (cont’d)
Step
5
6
7
8
9
10
Action
1. With the engine OFF and the ignition in the ON
position, monitor TPS percentage with Allison
DOC™ For PC–Service Tool.
2. Slowly increase the throttle from idle to full
throttle position.
3. Watch for a steady increase in TPS percentage.
Was the throttle percentage steady and without
interruptions?
1. Turn OFF the ignition.
2. Disconnect the TPS connector.
3. Using a DVOM, measure the resistance between
TPS pins A and C.
Is resistance within the specified value?
1. Reconnect the TPS connector.
2. Disconnect the J 47275 TCM Breakout from the
TCM. Leave the OEM 80-way connector mated
to the J 47275 TCM Breakout.
3. Using a DVOM, measure resistance between
80-way connector pins 12 and 58.
Is resistance within the specified value?
1. Turn OFF the ignition.
2. Disconnect the TPS connector.
3. Using a DVOM at J47275-1 TCM Overlay, test
for opens, wire-to-wire shorts, and shorts-toground at pin 44.
Were any opens, wire-to-wire shorts, or shorts-toground found?
1. Turn OFF the ignition.
2. Disconnect the 16-pin bypass connector on
J 47275 TCM breakout.
3. Turn ON the ignition.
4. Using a DVOM at J 47275-1 TCM Overlay,
measure voltage between pins 12 and 58.
Is the voltage within the specified value?
1. Turn OFF the ignition.
2. Disconnect the J 47275 TCM Breakout from the
TCM. Leave the OEM 80-way connector mated
to the J 47275 TCM Breakout.
3. Reconnect the 16-pin bypass connector on
J 47275 TCM Breakout.
4. Disconnect the TPS connector, transmission
20-way connector, and RMR device, if installed.
5. Using a DVOM at J 47275-1 TCM Overlay, test
for opens, wire-to-wire shorts, and shorts-toground at pin 12.
6. Test for opens at pin 58.
Were any opens, wire-to-wire shorts, or shorts-toground found?
Value(s)
Yes
Go to
Diagnostic Aids
No
Go to Step 6
9000−15,000
Ohms
Go to Step 7
Go to Step 11
9000−15,000
Ohms
Go to Step 8
Go to Step 10
Go to Step 10
Go to Step 11
Go to Step 10
Go to Step 13
Go to Step 11
Go to
Diagnostic Aids
4.75–5.0V
Copyright © 2005 General Motors Corp.
6–29
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0122 Pedal Position Sensor Low Voltage (cont’d)
Step
11
12
13
14
6–30
Action
NOTE: The vehicle OEM has responsibility for all
external wiring harness repairs. Harness repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Value(s)
Repair the vehicle wiring harness.
Is the repair complete?
Replace the throttle position sensor.
Is the replacement complete?
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
Refer to TCM diagnostic procedure, Section 3–6.
Is the replacement complete?
In order to verify your repair:
1. Clear the DTC.
2. Operate the vehicle under normal driving
conditions.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 14
No
Go to Step 14
Go to Step 14
Begin the
diagnosis again.
Go to Step 1
System OK
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0123 Pedal Position Sensor High Voltage
END VIEW OF
20-WAY CONNECTOR
END VIEW OF
80-WAY CONNECTOR
1
6
7
10
11
14
15
20
61
80
41
60
21
40
1
20
TO RETARDER
CONTROL DEVICES
RETARDER
REQUEST SENSOR
(RESISTANCE
MODULE)
A
PWM
THROTTLE
SOURCE
B
C
TCM
THROTTLE
POSITION
SENSOR (TPS)
OR
ELECTRONIC
BRAKING (EBS)
RTDR PRESSURE
SENSOR
WIRE 156
WIRE 112
C
WIRE 144
B
WIRE 158
A
RETARDER TEMP
ENGINE TEMP
TRANSMISSION
ANALOG RETURN
OIL LEVEL
HALL
A
C
EFFECT
B
SUMP TEMP
19
16
15
18
PS1
NC*
* NORMALLY
3
WIRE 175
WIRE 135
56
RETARDER REQUEST SIGNAL
12
5V SENSOR VOLTAGE
44
THROTTLE POSITION OR
RTDR PRESSURE SIGNAL
58
ANALOG RETURN
75
RETARDER TEMP
35
ENGINE WATER TEMP
16
OIL LEVEL SENSOR
54
SUMP TEMP
77
PS1 DIAGNOSTIC
PRESSURE SWITCH
WIRE 158
WIRE 112
WIRE 116
WIRE 154
WIRE 177
CLOSED
V09069.01.00
Copyright © 2005 General Motors Corp.
6–31
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0123 Pedal Position Sensor High Voltage
Circuit Description
The Transmission Control Module (TCM) receives input on throttle position from either a Throttle Position Sensor
(TPS) or a signal transmitted by the engine electronic controls.
Vehicles not equipped with electronically-controlled engines have a TPS attached to the engine fuel control
linkage. The TPS continuously sends the exact throttle position to the transmission TCM.
The TPS is a sliding resistor sensor (potentiometer) actuated by a mechanical linkage. The TCM delivers a constant
voltage to one terminal of the TPS resistive strip. The other TPS terminal connects to ground. The resistor contacts
of the TPS are connected to provide a regulated voltage signal input to the TCM.
When actuated by the mechanical throttle cable, the contacts of the resistor move along the resistive strip. As the
contacts slide along the resistive strip, a voltage is sent to the TCM. At each increment of 0.78 mm (0.007 inch)
along the resistive strip, the contacts deliver a different voltage to the TCM. The different voltages are interpreted
as throttle sensor movement. The TCM converts travel distance (mm) into throttle opening percentage.
Conditions for Running the DTC
• The components are powered and ignition voltage is greater than 9V and less the 18V (12V TCM) or greater
than 9V and less than 32V (24V TCM).
•
The components are powered and engine speed is greater than 200 rpm.
•
DTC P0123 Throttle/Pedal Position Sensor/Switch A Circuit Low Input is not active.
Conditions for Setting the DTC
DTC P0123 sets when the TCM detects a throttle position sensor voltage greater than 4.75V for 5 seconds.
Action Taken When the DTC Sets
• The TCM does not illuminate the CHECK TRANS light.
•
DTC P0123 is stored in the TCM history.
•
The TCM uses the default throttle value, based on engine torque and speed.
•
The TCM freezes shift adapts (DNA).
Conditions for Clearing the DTC/CHECK TRANS LIGHT
The Allison DOC™ For PC–Service Tool may be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without the DTC
recurring.
Diagnostic Aids
• Inspect the wiring for poor electrical connections at the TCM. Look for the following conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
• When diagnosing for an intermittent short or open, massage the wiring harness while watching the test
equipment for a change.
•
You may have to drive the vehicle in order to experience a fault.
6–32
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
•
DTC P0123 can be caused by a short-to-battery in either the 5V reference wire 112 or TPS signal wire 144.
DTC P0123 can also be caused by an open in analog return wire 158. The TPS shares a common 5V reference
voltage wire 112 with the transmission oil level sensor (OLS) and retarder request sensor. A short-to-battery in
5V reference wire or open in analog return wire 158 causes a “sensor failed high” code for the other devices as
well. A short-to-battery on TPS signal wire 144 will produce a DTC P0123 only.
Test Description
This DTC requires the use of the J 47275 TCM Breakout. The numbers below refer to step numbers on the
diagnostic table.
2. This step tests for the proper adjustment of TPS.
3. This step tests for the proper ignition voltage.
4. This step tests for the proper TCM 5V reference voltage.
5. This step tests for dead spots in the potentiometer.
6. This step tests for abnormal TPS resistance.
7. This step tests for proper resistance of the TPS circuit.
8. This step tests for a short-to-battery in TPS signal wire 144.
9. This step tests for proper 5V reference voltage at TCM without OEM harness.
10. This step tests for a short-to-battery in 5V reference wire 112 or open in analog return wire 158.
DTC P0123 Pedal Position Sensor High Voltage
Step
1
2
3
4
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
Refer to Appendix F to determine proper TPS
adjustment.
Is the TPS adjusted properly?
1. Install the Allison DOC™ For PC–Service Tool. 9−18V (12V TCM)
2. Start the engine.
18−32V (24V TCM)
3. Record the DTC failure record data.
4. Using the Allison DOC™ For PC–Service Tool,
measure ignition voltage.
Is voltage within the specified values?
1. Turn OFF the ignition.
4.75−5.0V
2. Disconnect the 80-way connector from the TCM
and install the J 47275 TCM Breakout between
the TCM and the OEM-side connector.
3. With the engine OFF, turn the ignition to the ON
position.
4. Using a DVOM, measure the voltage between
pins 12 and 58.
Is the voltage within the specified value?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 2
Go to Step 3
Go to Step 4
Go to Step 5
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Adjust TPS to
proper setting. Go
to Step 14
Resolve voltage
problem (refer to
DTC P0882 and
DTC P0883)
Go to Step 9
6–33
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0123 Pedal Position Sensor High Voltage (cont’d)
Step
5
6
7
8
9
10
6–34
Action
1. With the engine OFF and the ignition in the ON
position, monitor TPS percentage with Allison
DOC™ For PC–Service Tool.
2. Slowly increase the throttle from idle to full
throttle position.
3. Watch for a steady increase in TPS percentage.
Was TPS percentage steady and without
interruptions?
1. Turn OFF the ignition.
2. Disconnect the TPS connector.
3. Using a DVOM, measure the resistance between
TPS pins A and C.
Is resistance within the specified value?
1. Reconnect the TPS connector.
2. Disconnect the J 47275 TCM Breakout from the
TCM. Leave the OEM 80-way connector mated
to the J 47275 TCM Breakout.
3. Using a DVOM, measure resistance between
80-way connector pins 12 and 58.
Is resistance within the specified value?
1. Turn OFF the ignition.
2. Disconnect the TPS connector.
3. Using a DVOM at J 47275-1 TCM Overlay, test
for wire-to-wire shorts and shorts-to-battery at
pin 44.
Were any wire-to-wire shorts or shorts-to-battery
found?
1. Turn OFF the ignition.
2. Disconnect the 16-pin bypass connector on
J 47275 TCM breakout.
3. Turn ON the ignition.
4. Using a DVOM at J 47275-1 TCM Overlay,
measure voltage between pins 12 and 58.
Is the voltage within the specified value?
1. Turn OFF the ignition.
2. Disconnect the J 47275 TCM Breakout from the
TCM. Leave the OEM 80-way connector mated
to the J 47275 TCM Breakout.
3. Reconnect the 16-pin bypass connector on
J 47275 TCM Breakout.
4. Disconnect the TPS connector, transmission
20-way connector, and RMR connector, if
installed.
5. Using a DVOM at J 47275-1 TCM Overlay, test
for opens, wire-to-wire shorts, and shorts-toground at pin 12.
6. Test for opens at pin 58.
Were any opens, wire-to-wire shorts, or shorts-toground found?
Value(s)
Yes
Go to Step 6
No
Go to Step 12
9000−15,000
Ohms
Go to Step 7
Go to Step 11
9000−15,000
Ohms
Go to Step 8
Go to Step 10
Go to Step 9
Go to Step 11
Go to Step 10
Go to Step 13
Go to Step 11
Go to
Diagnostic Aids
4.75–5.0V
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0123 Pedal Position Sensor High Voltage (cont’d)
Step
11
12
13
14
Action
NOTE: The vehicle OEM has responsibility for all
external wiring harness repairs. Harness repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Value(s)
Repair the vehicle wiring harness.
Is the repair complete?
Replace the throttle position sensor.
Is the replacement complete?
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
Refer to TCM diagnostic procedure, Section 3–6.
Is the replacement complete?
In order to verify your repair:
1. Clear the DTC.
2. Operate the vehicle under normal driving
conditions.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 14
No
Go to Step 14
Go to Step 14
Begin the
diagnosis again.
Go to Step 1
System OK
6–35
6–36
TORQUE
CONVERTER
LOCKUP
CONVERTER IN
CONVERTER OUT
Copyright © 2005 General Motors Corp.
COOLER/LUBE
EX. BACKFILL
CONVERTER
SUCTION
LEGEND:
CONVERTER
FLOW
EX
TCC
SOL
EX
SUCTION
EX
FORWARD
KNOCKDOWN
TO
CLUTCHES
AND
CONTROL
MAIN
CIRCUIT
TO COOLER
COOLER/LUBE
EX. BACKFILL
CONVERTER
MAIN MOD
FROM LUBE
CONVERTER
REGULATOR
LOCKUP PRESSURE
MAIN
REGULATOR
CONVERTER FLOW CIRCUIT
EX
MAIN
FILTER
V09282.00.00.eps
SUMP
SUCTION
FILTER
PUMP
EX
Pressure
Relief
MAIN
MAIN MOD
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0218 Transmission Fluid Over-Temperature
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0218 Transmission Fluid Over-Temperature
Circuit Description
Transmission fluid flow starts in the transmission sump. Fluid is drawn into the oil pump assembly through the
suction filter and internal passages in the main housing and front support. The gerotor gear set in the oil pump
assembly turns at engine speed and pressurizes the fluid. The main regulator valve regulates the discharge pressure at
the oil pump. Pressurized fluid returns to the hydraulic control module where it is directed to the clutch apply circuits
and the control main regulator valve. Control main pressure is used to stroke solenoid regulator valves, which apply
and release transmission clutches in response to solenoid commands from the Transmission Control Module (TCM).
The main pump produces substantially more fluid flow than is required by the clutch apply circuit. Surplus oil
pressure (overage) at the main regulator valve is relieved into the converter flow circuit. The converter flow circuit
routes pressurized fluid to the torque converter via the converter flow valve and the converter regulator valve. Hot
fluid leaving the torque converter is routed back through the converter flow valve into cooler lines that run to the
transmission oil cooler in the vehicle cooling system. The cooled fluid is returned to the transmission and enters the
transmission lubrication circuit. The lube regulator valve regulates the proper lubrication pressure and directs
excess fluid back to the sump. The transmission fluid temperature sensor is part of the internal wiring harness and
measures the sump temperature.
Conditions for Running the DTC
• The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater
than 9V and less than 32V (24V TCM).
• The components are powered and engine speed is greater than 200 rpm and less than 7500 rpm for 5 seconds.
• Engine is running. If engine runtime is less than 10 minutes, then engine coolant temperature must be above
20°C (68°F) for more than 20 seconds.
Conditions for Setting the DTC
The TCM detects transmission fluid temperature greater than 126.85°C (260°F) value for more than 10 seconds.
Actions Taken When the DTC Sets
When DTC P0218 is active, the following conditions will occur:
• The TCM does not illuminate the CHECK TRANS light.
• DTC is stored in TCM history.
• The TCM freezes shift adapts (DNA).
• TCM defaults to “hot mode” shift schedule where fourth range is held and TCC is inhibited to increase engine
speed and improve cooler flow.
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
The TCM cancels the DTC default actions when the fault no longer exists and the DTC passes test.
Diagnostic Aids
• The Allison DOC™ For PC–Service Tool transmission fluid temperature should rise steadily during warm-up
cycles and then stabilize.
• DTC P0218 may set after DTC P0711 (not active) has set. Follow the diagnostic table for DTC P0711 before
proceeding to the diagnostic table for P0218. Repairing the condition that set DTC P0711 will likely eliminate
DTC P0218.
• A stuck autoflow valve can cause overheating in retarder-equipped transmissions. Refer to section 8 for general
troubleshooting of performance complaints.
Copyright © 2005 General Motors Corp.
6–37
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
Test Description
This DTC requires the use of the J 47275 TCM Breakout and J 47279 Transmission Breakout. The numbers below
refer to step numbers on the diagnostic table.
2. This step tests for proper transmission fluid level and condition.
3. This step monitors the status of DTC P0218.
4. This step verifies which condition has set the DTC P0218.
5. This step tests for proper resistance value in entire circuit.
6. This step tests for wire-to-wire shorts, shorts-to-ground, or an open on wire 154.
7. This step tests the resistance value of the internal harness and sump temperature sensor.
9. This step tests the resistance value of the internal sump temperature sensor.
12. This step tests to determine source of overheat—the engine or transmission.
13. This step tests for proper cooler pressure drop.
14. This step tests for stuck stator.
15. This step inspects vehicle’s engine and transmission cooling systems.
DTC P0218 Transmission Fluid Over-Temperature
Step
1
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
2
Perform the Fluid Check Procedure. Refer to the
appropriate mechanic’s tips.
Is transmission fluid level correct?
1. Install the Allison DOC™ For PC–Service Tool.
2. Install temperature gauges for transmission
temperature and engine water temperature.
3. Turn ON the ignition.
4. Record the failure records.
5. Clear the DTCs.
6. Drive the vehicle and monitor the sump
temperature on Allison DOC™ For PC–Service
Tool.
Did DTC P0218 return?
Compare the manual temperature gauge reading to
the Allison DOC For PC–Service Tool
transmission temperature when the DTC is set.
Does the manual temperature gauge confirm the
transmission fluid temperature actually is hot when
DTC P0218 is produced?
3
4
6–38
Value(s)
Copyright © 2005 General Motors Corp.
Yes
Go to Step 2
Go to Step 3
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Go to
mechanic’s tips
Go to Step 4
Go to
Diagnostic Aids
Go to Step 12
Go to Step 5
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0218 Transmission Fluid Over-Temperature (cont’d)
Step
5
6
7
8
9
10
11
Action
1. Turn the ignition OFF.
2. Disconnect the 80-way connector from the TCM.
3. Connect J 47425 TCM Breakout to the OEM
connector. Leave the TCM disconnected. The
TCM should not be connected to properly
perform this test.
4. Using a DVOM at J 47275-1 TCM Overlay,
measure the resistance between pins 54 and 58.
Is the resistance within the specified value?
1. Disconnect the transmission 20-way connector,
TPS, and RMR, if installed.
2. At J 47275-1 TCM Overlay connect a DVOM,
test for opens, wire-to-wire shorts, and shorts-toground at pin 54 and 58.
Were any wiring defects found?
1. Disconnect the 20-way connector at the
transmission and install J 47279 Transmission
Breakout. Connect only the J 47279 Transmission
Breakout to the transmission; the vehicle side of
the harness should not be connected for this test.
2. At J 47279-1 Transmission Overlay, using a
DVOM, measure resistance at main transmission
connector pins 18 and 19.
Is the resistance within the specified value?
NOTE: The vehicle OEM has responsibility for all
external wiring harness repairs. Harness repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Coordinate with the vehicle OEM to repair or
replace the vehicle wiring.
Is the repair complete?
1. Remove the hydraulic control module assembly.
2. Disconnect the sump thermistor from the internal
wiring harness.
3. Using a DVOM, measure thermistor resistance at
pins A and B.
Is resistance within the specified values?
Replace the internal harness (refer to mechanic’s
tips).
Is the replacement complete?
Replace the sump thermistor (refer to mechanic’s
tips).
Is replacement complete?
Value(s)
3511–3653 Ohms
at 20°C (68°F)
Refer to
Appendix Q
3511–3653 Ohms
at 20°C (68°F)
Refer to
Appendix Q
Yes
Go to Step 6
No
Go to Step 7
Go to Step 8
Go to Step 16
Go to Step 8
Go to Step 9
Go to Step 17
3511–3653 Ohms
at 20°C (68°F)
Refer to
Appendix Q
Copyright © 2005 General Motors Corp.
Go to Step 10
Go to Step 11
Go to Step 17
Go to Step 17
6–39
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0218 Transmission Fluid Over-Temperature (cont’d)
Step
12
13
14
15
16
17
6–40
Action
Value(s)
1. Use temperature gauge readings obtained in
Step 4 above.
2. Compare engine water temperature to
transmission fluid temperature.
Did the transmission become hot before the engine?
1. Install pressure gauges in the “To” and “From”
Refer to Table 6–5
cooler lines.
for 4000 Product
2. Start the engine.
Family.
Refer
to Table 6–6
3. Subtract “From Cooler” from “To Cooler”
pressure to obtain pressure drop across the
for 3000 Product
transmission oil cooler.
Family
4. Verify cooler pressure drop satisfies limits of
Table 6–5 (4000 Product Family) or Table 6–6
(3000 Product Family).
Is cooler pressure drop within specified values?
Check for a possible torque converter stator
malfunction. A stuck stator would be indicated by no
cool-down in Neutral after stalling the transmission.
Refer to appropriate service manual for Stall Test
Procedures.
Did you find and correct the condition?
1. Inspect the engine cooling system for the
following conditions:
• Air flow restrictions
• Air flow blockage
• System fluid level and condition
• Debris
2. Inspect the transmission cooling system for the
following conditions:
• Air flow restrictions
• Air flow blockage
• System fluid level and condition
• Damaged cooler lines and hoses
Did you find and correct the condition?
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
Refer to TCM diagnostic procedure, Section 3–6.
Is Section 3–6 complete?
In order to verify your repair:
1. Clear the DTC.
2. Using Allison DOC™ For PC–Service Tool,
monitor the transmission fluid temperature.
3. Drive the vehicle under normal operating
conditions. Watch for significant change in TFT.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 13
No
Go to Step 15
Go to Step 14
Go to Step 15
Go to Step 17
Go to Section 8,
General
Troubleshooting of
Performance
Complaints
Go to Step 17
Go to Step 17
Begin the
diagnosis again.
Go to Step 1
System OK
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0218 Transmission Fluid Over-Temperature
External Hydraulic Circuit Characteristics
Basic, PTO, 93°C (200°F) Sump Temperature
Table 6–5. 4000 Product Family
CONVERTER OPERATION
MAXIMUM COOLER FLOW AT MINIMUM PRESSURE DROP
Flow
Pressure Drop
Input rpm
L/s
gpm
kPa
psi
600
0.22
3.4
0
0
900
0.38
6.1
0
0
1200
0.55
8.7
0
0
1500
0.80
12.7
0
0
1800
1.03
16.4
0
0
2100
1.13
18.0
0
0
2300
1.20
19.0
0
0
CONVERTER OPERATION
COOLER FLOW AT MAXIMUM ALLOWABLE PRESSURE DROP
600
0.20
3.2
31.0
4.5
900
0.37
5.8
63.0
9.1
1200
0.55
8.7
108.0
15.7
1500
0.77
12.2
167.0
24.2
1800
0.92
14.5
231.0
30.9
2100
0.97
15.3
238.0
34.5
2300
1.00
15.9
250.0
36.3
Copyright © 2005 General Motors Corp.
6–41
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0218 Transmission Fluid Over-Temperature
External Hydraulic Circuit Characteristics
Basic, PTO, 93°C (200°F) Sump Temperature
Table 6–6. 3000 Product Family
CONVERTER OPERATION
MAXIMUM COOLER FLOW AT MINIMUM PRESSURE DROP
Flow
Pressure Drop
Input rpm
L/s
gpm
kPa
psi
600
0.10
1.6
0
0
800
0.23
3.7
0
0
1200
0.47
7.4
0
0
1400
0.61
9.7
0
0
1600
0.74
11.7
0
0
2000
0.94
14.9
0
0
2400
1.19
18.9
0
0
3200
1.28
20.3
0
0
CONVERTER OPERATION
MAXIMUM ALLOWABLE PRESSURE DROP
600
0.10
1.6
10.0
1.5
800
0.23
3.5
40.0
5.8
1200
0.45
7.1
159.0
23.1
1400
0.57
9.0
252.0
36.6
1600
0.67
10.6
338.0
49.0
2000
0.80
12.7
481.0
69.8
2400
0.85
13.5
549.0
79.6
3200
0.85
13.5
549.0
79.6
LOCKUP OPERATION
MAXIMUM COOLER FLOW AT MINIMUM PRESSURE DROP
600
0.10
1.6
0
0
800
0.23
3.7
0
0
1200
0.50
7.9
0
0
1400
0.63
10.0
0
0
1600
0.77
12.2
0
0
2000
0.95
15.1
0
0
2400
1.12
17.8
0
0
2800
1.22
19.3
0
0
3200
1.28
20.3
0
0
LOCKUP OPERATION
MAXIMUM ALLOWABLE PRESSURE DROP
600
0.10
1.6
5.0
0.7
800
0.23
3.7
46.0
6.7
1200
0.48
7.6
148.0
21.5
1400
0.62
9.8
247.0
35.8
1600
0.73
11.6
346.0
50.2
2000
0.90
14.3
561.0
81.4
2400
1.07
17.0
737.0
106.9
2800
1.10
17.4
770.0
111.7
3200
1.10
17.4
791.0
114.7
6–42
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0602 TCM Not Programmed
NO SCHEMATIC FOR THIS DTC
Circuit Description
At power up and after clearing codes, the Transmission Control Module (TCM) performs a self-test to determine if
the calibration in memory is valid.
Conditions for Running the DTC
This test will run before any TCM functions.
Conditions for Setting the DTC
DTC P0602 sets if the TCM determines the present calibration is invalid.
Actions Taken When the DTC Sets
•
The CHECK TRANS light illuminates.
•
DTC is stored in TCM history.
•
The TCM returns to the boot program, and waits to be recalibrated.
•
TCM inhibits shifts to range.
Conditions for Clearing the DTC/CHECK TRANS Light
The TCM must be recalibrated.
DTC P0602 TCM Not Programmed
Step
1
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
2
1. Install the Allison DOC™ For PC–Service Tool.
2. If DTC P0602 is present, the TCM must be
recalibrated.
Is recalibration complete?
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
3
4
Value(s)
Refer to TCM diagnostic procedure, Section 3–6.
Is Section 3–6 complete?
1. Install the Allison DOC™ For PC–Service Tool.
2. Start the vehicle.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 2
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Go to Step 4
Go to Step 4
Go to Step 3
System OK
6–43
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0610 TCM Vehicle Options (TransID) Error
END VIEW OF
80-WAY CONNECTOR
END VIEW OF
20-WAY CONNECTOR
1
6
7
10
11
14
15
20
61
80
41
60
21
40
1
20
TRANSMISSION
TRANSID
HSD1
PCS4
PCS6
MAIN MOD
TCM
WIRE 176
20
WIRE 111
1
WIRE 155
2
WIRE 178
7
WIRE 174
8
76
11
TRANSID
HSD1
ANALOG
INTERFACE
55
78
V BATTERY
74
V09066.00.00
Circuit Description
The TransID (TID) feature enables the TCM to recognize various transmission hardware configurations and select
an appropriate software calibration. The TCM senses the transmission configuration using TID wire 176. In initial
versions of 4th Generation Controls, wire 176 is connected to High Side Driver 1 (HSD1), wire 111, in the internal
wiring harness. HSD1 supplies power to the Main Mod solenoid, and Pressure Control Solenoids (PSC) 4 and 6.
This wiring configuration is designated TID A.
Conditions for Running the DTC
The test is enabled by the TCM calibration.
Conditions for Setting the DTC
DTC P0610 sets if the TCM determines the controls are incompatible with transmission hardware.
Actions Taken When the DTC Sets
•
The CHECK TRANS light illuminates.
•
DTC is stored in TCM history.
•
The TCM uses a TID A calibration.
6–44
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
DTC P0610 TCM Vehicle Options (TransID) Error
Step
1
2
3
4
5
6
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
1. Install the Allison DOC™ For PC–Service Tool.
2. Turn ON the ignition.
3. Using Allison DOC™ For PC–Service Tool,
determine the highest available TID level
supported by the TCM calibration.
4. Consult the transmission bill of material or build
history to determine the actual TID level of the
transmission.
5. Compare the highest available TID level in the
calibration to the actual transmission hardware.
Is the highest available TID level greater than or
equal to the actual TID of the transmission?
1. Reset Autodetect using Allison DOC™ For PC–
Service Tool.
2. Monitor “TransID level Used” on Allison DOC™
For PC–Service Tool.
3. Compare the TID level indicated on Allison
DOC™ For PC–Service Tool to the actual TID
level of the transmission.
Did the TCM detect the correct TID level?
Recalibrate the TCM with a TID calibration that
matches the actual TID level of the transmission.
Is the recalibration complete?
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
Refer to TCM diagnostic procedure, Section 3–6.
Is Section 3–6 complete?
In order to verify your repair:
1. Clear the DTC.
2. Using Allison DOC™ For PC–Service Tool, reset
Autodetect.
3. Verify the TCM detects the correct TID level.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 2
Go to Step 3
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Go to Step 4
Go to Step 6
Go to Step 5
Go to Step 6
Go to Step 6
Begin the
diagnosis again.
Go to Step 1
System OK
6–45
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0613 TCM Processor
NO SCHEMATIC FOR THIS DTC
Circuit Description
The Transmission Control Module (TCM) continually performs a series of processing steps known as a ‘processing
loop’ during normal operation. The TCM must complete the processing loop within a specific time limit. The TCM
will reset if it does not complete two consecutive loops inside a predetermined time interval.
NOTE:
The presence of DTC P0613 indicates a TCM processing error has occurred. Contact the Allison
Transmission Service Department at 1-800-252-5283.
Conditions for Running the DTC
This test is run during the entire ignition cycle.
Conditions for Setting the DTC
DTC P0613 sets if the TCM does not complete two processing loops within the allotted time.
Actions Taken When the DTC Sets
• When DTC P0613 is active, the TCM commands OFF all solenoids (SOL OFF). Following recovery from the
processor reset, the TCM commands the range that resulted after solenoids were commanded OFF. The TCM
resumes normal operation.
•
The TCM does not illuminates the CHECK TRANS light.
•
DTC is stored in TCM history.
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
6–46
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0614 Torque Control Data Mismatch—ECM/TCM
NO SCHEMATIC FOR THIS DTC
Circuit Description
Shift Energy Management (SEM) allows the Transmission Control Module (TCM) to request torque reduction
from the engine controller. By reducing torque, shifts can be made quicker, at a more consistent output torque
which reduces clutch temperatures and increases clutch life. When an engine torque rating exceeds a
predetermined value, Low Range Torque Protection (LRTP), is used. This feature limits engine torque in lower
ranges to protect the transmission from damage during a stall condition.
Conditions for Running the DTC
•
TCM detects a J1939 EEC1 message from the engine.
•
Then, the TCM requests the J1939 component ID and engine configuration messages from the engine.
•
The TCM identifies the engine as an approved “make and model” by matching the component ID with the
engine configuration message.
•
The test runs for 15 seconds for the first 20 engine starts after the engine is detected on the J1939
communications link.
•
The “engine start” counter resets if the TCM is reprogrammed.
Conditions for Setting the DTC
DTC P0614 sets during the following conditions:
•
The TCM requires a SEM engine but the engine does not support SEM, i.e., is not on the approved list.
•
The TCM requires a SEM and LRTP engine but the engine does not support SEM and LRTP, i.e., is not on the
approved list.
•
The engine does not respond to a SEM torque reduction request message within 20 ignition cycles.
•
The engine does not respond to a LRTP torque reduction request message within 20 ignition cycles.
Actions Taken When the DTC Sets
When DTC P0614 is active, the following conditions will occur:
•
The CHECK TRANS light illuminates.
•
DTC is stored in TCM history.
•
The TCM will allow operation in Reverse and second range only.
•
TCM freezes shift adapts (DNA).
•
TCM inhibits the torque converter clutch (TCC).
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Copyright © 2005 General Motors Corp.
6–47
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
Test Description
The numbers below refer to step numbers on the diagnostic table.
3. This step verifies the engine is on the recognized list of SEM/LRTP engines.
4. This step verifies the engine supports SEM.
5. This step verifies the engine supports LRTP.
DTC P0614 Torque Control Data Mismatch—ECM/TCM
Step
1
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
2
If a DTC U0115 is present, troubleshoot and resolve
before going to the next step.
Is a DTC U0115 present?
3
1. Install the Allison DOC™ For PC–Service Tool.
2. Turn ON the ignition.
3. Refer to Engine Hardware Status in SEM/
LRTP AND AUTODETECT INFO display of
Allison DOC™ For PC–Service Tool.
Is the Engine Hardware Status recognized as a SEM/
LRTP capable engine?
Refer to SEM Validated Status in SEM/LRTP
AND AUTODETECT INFO display of Allison
DOC™ For PC–Service Tool.
Does the ECM support SEM?
Refer to LRTP Validated Status in SEM/LRTP
AND AUTODETECT INFO display of Allison
DOC™ For PC–Service Tool.
Does the ECM support LRTP?
This indicates the engine torque values are above the
transmission ratings set in the TCM calibration.
1. Inspect the TCM for proper calibration to support
SEM and LRTP. If proper TCM calibration is
installed, the engine rating is too high for the
transmission.
2. Recalibrate the engine to a lower torque rating.
Was one of the above conditions found and
resolved?
Turn over the vehicle to the engine manufacturer to
install the proper engine software and calibration to
support SEM and/or LRTP.
Has the proper software and calibration been
installed?
4
5
6
7
6–48
Value(s)
Yes
Go to Step 2
Go to DTC U0115
and resolve before
proceeding to
Step 8
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Go to Step 3
Recognized
Or
Not Recognized
Go to Step 4
Go to Step 7
ECM Supports
SEM Or
ECM Doesn’t
Support SEM
Go to Step 5
Go to Step 7
ECM Supports
LRTP Or
ECM Doesn’t
Support LRTP
Go to Step 6
Go to Step 7
Copyright © 2005 General Motors Corp.
Go to Step 8
Go to Step 8
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0614 Torque Control Data Mismatch—ECM/TCM (cont’d)
Step
8
Action
In order to verify your repair:
1. Using Allison DOC™ For PC–Service Tool, reset
SEM AUTOSELECT. Refer to Section 3–8.
2. Clear the DTC.
3. Drive the vehicle under normal operating
conditions.
Did the DTC return?
Value(s)
Copyright © 2005 General Motors Corp.
Yes
Begin the
diagnosis again.
Go to Step 1
No
System OK
6–49
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0634 TCM Internal Temperature Too High
NO SCHEMATIC FOR THIS DTC
Circuit Description
The Transmission Control Module (TCM) is equipped with an internal temperature sensor mounted directly to its
circuit board. The TCM will take action to protect against damage from overheat.
Conditions for Running the DTC
•
The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater
than 9V and less than 32V (24V TCM).
•
Engine speed is greater than 200 rpm and less than 7500 rpm for more than 10 seconds.
Conditions for Setting the DTC
DTC P0634 sets if the TCM internal temperature is greater than or equal to 140°C (284°F) for 10 seconds with
engine running.
Actions Taken When the DTC Sets
•
The CHECK TRANS light illuminates.
•
DTC is stored in TCM history.
•
The TCM commands OFF all solenoids (SOL OFF).
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
Clean the TCM if necessary. Excessive road debris will reduce the effectiveness of the heat sink on the TCM and
could cause internal temperature to rise.
DTC P0634 TCM Internal Temperature Too High
Step
1
2
6–50
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
1.
2.
3.
4.
5.
Install the Allison DOC™ For PC–Service Tool.
Turn ON the ignition.
Record the failure records.
Clear the DTCs.
Drive the vehicle and monitor TCM internal
temperature on Allison DOC™ For PC–Service
Tool.
Did DTC P0634 return?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 2
Go to Step 3
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Go to
Diagnostic Aids
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0634 TCM Internal Temperature Too High (cont’d)
Step
3
4
5
Action
1. Inspect the TCM and surrounding area.
2. Be sure there are no high temperature
components such as engine exhaust pipes
mounted in the vicinity of the TCM.
3. Shield or relocate the TCM, if possible.
Do you find and correct the problem?
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
Value(s)
Refer to TCM diagnostic procedure, Section 3–6.
Is Section 3–6 complete?
In order to verify your repair:
1. Install Allison DOC™ For PC–Service Tool.
2. Monitor TCM internal temperature.
3. Drive the vehicle under conditions noted in
failure records.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 5
No
Go to Step 4
Go to Step 5
Begin the
diagnosis again.
Go to Step 1
System OK
6–51
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P063E Auto Configuration Throttle Input Not Present
NO SCHEMATIC FOR THIS DTC
Circuit Description
When first activated and during the first group of power-on cycles, the Transmission Control Module (TCM)
searches for a valid throttle input. The TCM may receive throttle input from an analog throttle position sensor, a
pulse-width modulated (PWM) throttle source, or over one of the SAE digital data links as accelerator pedal
position and/or percent engine load. The TCM logs a DTC P063E if it fails to detect a throttle source during
autodetect.
Conditions for Running the DTC
The test is enabled by the TCM calibration.
Conditions for Setting the DTC
DTC P063E sets if the TCM fails to detect throttle position information for a specified time interval.
Actions Taken When the DTC Sets
•
The CHECK TRANS light illuminates.
•
DTC is stored in TCM history.
•
The TCM uses default throttle values.
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Test Description
The numbers below refer to step numbers on the diagnostic table.
2. This step tests to see if TCM is reading throttle information.
3. This step determines what throttle source the vehicle manufacturer intends to use.
4. This step looks for throttle information on the data link.
DTC P063E Auto Configuration Throttle Input Not Present
Step
1
6–52
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
Copyright © 2005 General Motors Corp.
Yes
Go to Step 2
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P063E Auto Configuration Throttle Input Not Present (cont’d)
Step
2
3
4
5
6
7
8
Action
Turn OFF the ignition.
Install the Allison DOC™ For PC–Service Tool.
Turn ON the ignition.
Using Allison DOC™ For PC–Service Tool,
determine the throttle source being used by the
TCM.
5. Depress and release the accelerator pedal while
monitoring throttle percentage on Allison DOC™
For PC–Service Tool.
Does throttle percentage on Allison DOC™ For PC–
Service Tool respond as expected to changes in the
accelerator pedal position?
Consult with the engine or vehicle manufacturer.
Determine if the vehicle is using a digital data link
(SAE J1587, SAE J1939 or IES CAN) to
communicate pedal position or percent engine load.
Otherwise, determine if the vehicle is using an
analog or PWM throttle position sensor.
Did the vehicle manufacturer intend to communicate
throttle position to the TCM over a digital data link?
1. Monitor Data Bus Viewer on Allison DOC™ For
PC–Service Tool.
2. Depress and release the accelerator pedal while
watching the Data Bus Viewer.
Does accelerator pedal position information on Data
Bus Viewer respond as expected to changes in
accelerator pedal position?
Using Allison DOC™ For PC–Service Tool attempt
to manually select the TCM throttle source to a data
link with valid throttle information.
Did the TCM detect a throttle source?
Coordinate with the vehicle or engine manufacturer
to determine the cause of loss of throttle information
on the data link.
Is the repair complete?
Coordinate with the vehicle or engine manufacturer
to repair the analog or PWM throttle sensor.
Is the repair complete?
In order to verify your repair:
1. Clear the DTC.
2. Drive the vehicle.
3. Using Allison DOC™ For PC–Service Tool,
monitor throttle percent.
4. Verify the TCM detects a valid throttle source.
Did the DTC return?
Value(s)
1.
2.
3.
4.
Copyright © 2005 General Motors Corp.
Yes
Go to Step 7
No
Go to Step 3
Go to Step 4
Go to Step 7
Go to Step 5
Go to Step 6
Go to Step 8
Go to Step 6
Go to Step 8
Go to Step 8
Begin the
diagnosis again.
Go to Step 1
System OK
6–53
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P063F Auto Configuration Engine Coolant Temp Input Not Present
NO SCHEMATIC FOR THIS DTC
Circuit Description
When first activated and during the first group of power-on cycles, the Transmission Control Module (TCM)
searches for a valid engine coolant temperature input. The TCM may receive engine coolant temperature input
from an analog temperature sensor, or from one of the SAE digital data links. The TCM logs a DTC P063F if it
fails to detect an engine coolant temperature source during autodetect.
Conditions for Running the DTC
The test is enabled by the TCM calibration.
Conditions for Setting the DTC
DTC P063F sets if the TCM fails to detect engine coolant temperature information for a specified time interval.
Actions Taken When the DTC Sets
• The TCM does not illuminate the CHECK TRANS light.
•
DTC is stored in TCM history.
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Test Description
The numbers below refer to step numbers on the diagnostic table.
2. This step tests to see if TCM is reading engine coolant information.
3. This step determines what engine coolant temperature source the vehicle manufacturer intends to use.
4. This step looks for engine coolant temperature information on the data link.
DTC P063F Auto Configuration Engine Coolant Temp Input Not Present
Step
1
2
6–54
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
1.
2.
3.
4.
Turn OFF the ignition.
Install the Allison DOC™ For PC–Service Tool.
Start the engine.
Using Allison DOC™ For PC–Service Tool,
determine the engine coolant temp source being
used by the TCM.
5. Allow the engine to warm-up and monitor engine
coolant temp on Allison DOC™ For PC–Service
Tool.
Does engine coolant temperature on Allison DOC™
For PC–Service Tool slowly rise as the engine
warms?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 2
Go to Step 7
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Go to Step 3
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P063F Auto Configuration Engine Coolant Temp Input Not Present (cont’d)
Step
3
4
5
6
7
8
Action
Consult with the engine or vehicle manufacturer.
Determine if the vehicle is using a digital data link
(SAE J1587, SAE J1939 or IES CAN) to
communicate engine coolant temperature.
Otherwise, determine if the vehicle is using an
analog engine coolant temperature sensor.
Did the vehicle manufacturer intend to communicate
engine coolant temperature to the TCM over a
digital data link?
1. Monitor Data Bus Viewer on Allison DOC™ For
PC–Service Tool.
2. Allow the engine to warm-up and watch the Data
Bus Viewer.
Does engine coolant temperature information on
Data Bus Viewer respond as expected as the engine
warms?
Using Allison DOC™ For PC–Service Tool attempt
to manually select the engine coolant temperature
source to a data link with valid information.
Did the TCM detect an engine coolant temperature
source?
Coordinate with the vehicle or engine manufacturer
to determine the cause of loss of engine coolant
temperature information on the data link.
Is the repair complete?
Coordinate with the vehicle or engine manufacturer
to repair the analog engine coolant temperature
sensor.
Is the repair complete?
In order to verify your repair:
1. Clear the DTC.
2. Drive the vehicle.
3. Using Allison DOC™ For PC–Service Tool,
monitor engine coolant temperature.
4. Verify the TCM detects a valid engine coolant
source.
Did the DTC return?
Value(s)
Copyright © 2005 General Motors Corp.
Yes
Go to Step 4
No
Go to Step 7
Go to Step 5
Go to Step 6
Go to Step 8
Go to Step 6
Go to Step 8
Go to Step 8
Begin the
diagnosis again.
Go to Step 1
System OK
6–55
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0658 Actuator Supply Voltage 1 (HSD1) Low
END VIEW OF
80-WAY CONNECTOR
END VIEW OF
20-WAY CONNECTOR
1
6
7
10
11
14
15
20
61
80
41
60
21
40
1
20
TRANSMISSION
TRANSID
HSD1
PCS4
PCS6
MAIN MOD
TCM
WIRE 176
20
WIRE 111
1
WIRE 155
2
WIRE 178
7
WIRE 174
8
76
11
TRANSID
HSD1
ANALOG
INTERFACE
55
78
V BATTERY
74
V09066.00.00
Circuit Description
High Side Driver 1 (HSD1) supplies battery voltage to the Main Mod, PCS4 and PCS6 solenoids via wire 111.
HSD1 is continuously ON during normal operation except during brief circuit tests. The TCM regulates control
current to the solenoids by switching the appropriate Low Side Driver (LSD) ON and OFF. DTC P0658 indicates
the TCM has detected a supply voltage in the HSD1 circuit of 6V or less. DTC P0658 could be caused by a shortto-ground in the high side wiring attached to HSD1 (wire 111).
Conditions for Running the DTC
•
The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater
than 9V and less than 32V (24V TCM).
•
HSD1 is commanded ON.
•
Engine speed greater than 200 rpm.
Conditions for Setting the DTC
DTC P0658 is set when the TCM detects a low voltage condition (less than 6V) in two solenoids in the HSD1
circuit.
6–56
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
Actions Taken When the DTC Sets
When DTC P0658 is active, the following conditions will occur:
•
The CHECK TRANS light illuminates.
•
DTC is stored in TCM history.
•
The TCM commands OFF all solenoids (SOL OFF). The shift selector position and hydraulic state of latch
valves determines the range attained.
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
•
You may have to drive the vehicle in order to experience a fault. Use the data obtained from failure records to
determine transmission range and/or certain vehicle operating variables such as temperature, run time, etc. This
data can be useful in reproducing the failure mode when DTC was set.
•
Inspect the wiring for poor electrical connections at the TCM and transmission connector. Look for the
following conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
•
Inspect OEM wiring harness routing, look for possible contact points where chafing could occur leading to an
open or short circuit condition. Moving parts on the vehicle could be contacting the harness; this includes
parking brake drum, suspension components, etc.
•
When diagnosing for an intermittent short or open, massage the wiring harness while watching the test
equipment for a change.
Test Description
This DTC requires the use of the J 47275 TCM Breakout and J 47279 Transmission Breakout. The numbers below
refer to step numbers on the diagnostic table.
2. This step tests for the proper ignition voltage.
3. This step tests for an active DTC.
4. This step tests for a wire-to-wire short, or short-to-ground in the wire 111 of the OEM chassis harness.
6. This step tests for wiring defects in the transmission internal harness.
DTC P0658 Actuator Supply Voltage 1 (HSD1) Low
Step
1
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
Copyright © 2005 General Motors Corp.
Yes
Go to Step 2
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
6–57
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0658 Actuator Supply Voltage 1 (HSD1) Low (cont’d)
Step
2
3
Action
Value(s)
1. Install the Allison DOC™ For PC–Service Tool. 9–18V (12V TCM)
18–32V (24V TCM)
2. Start the engine.
3. Record the failure records.
4. Monitor ignition voltage.
Is the voltage within the specified values?
1. Clear the DTC.
2. Start the engine and test drive the vehicle.
3. Attempt to duplicate the same conditions
observed in the failure records (range attained,
temperature, etc.).
Yes
Go to Step 3
No
Resolve voltage
problem
Go to Step 4
Go to
Diagnostic Aids
Go to Step 5
Go to Step 6
NOTE: This DTC is intended to detect a short-toground condition in the HSD1 electrical circuit.
4
5
Did DTC P0658 return?
1. Turn OFF ignition.
2. Disconnect the 80-way connector at the TCM.
3. Install the OEM-side of the 80-way connector to
the J 47275 TCM Breakout. Leave the TCM
disconnected.
4. Disconnect the OEM 20-way connector from the
transmission.
5. Inspect the routing of wire 111 in the chassis
harness between the TCM and transmission
connector.
6. At J 47275-1 TCM Overlay, test for wire-to-wire
shorts between pin 11and and all other pins in the
80-way connector, and test for short-to-ground
between pin 11 and chassis ground.
Were any wire-to-wire shorts or shorts-to-ground
found?
NOTE: The vehicle OEM has responsibility for all
external wiring harnesses and vehicle input/output
switch repair. Harness and switch repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Coordinate with the vehicle OEM to repair or
replace the vehicle wiring or switch.
Is the repair complete?
6–58
Copyright © 2005 General Motors Corp.
Go to Step 9
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0658 Actuator Supply Voltage 1 (HSD1) Low (cont’d)
Step
6
Action
1. Turn OFF the ignition.
2. Install the transmission 20-way connector to the
J 47279 Transmission Breakout. Leave the OEMside disconnected.
3. Using a DVOM at J 47279-1 Transmission
Overlay, test for wire-to-wire shorts between
pin 1 and all other pins in the 20-way connector,
and shorts-to-ground between pin 1 and chassis
ground.
Value(s)
Yes
Go to Step 7
No
Go to Step 8
NOTE: The resistance value between pins 1 and 2,
between pins 1 and 7 (7-speed models), and between
pins 1 and 8 will read normal solenoid resistance.
The resistance value between pin 1 and pin 20 (TID
wire) will read 0 Ohms.
7
8
9
Were any wire-to-wire shorts, or shorts-to-ground
found?
1. Remove the hydraulic control module assembly.
2. Repair or replace the internal wiring harness.
Is the repair complete?
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
Refer to TCM diagnostic procedure, Section 3–6.
Is Section 3–6 complete?
In order to verify your repair:
1. Clear the DTC.
2. Drive the vehicle under conditions noted in
failure records.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Go to Step 9
Go to Step 9
Begin the
diagnosis again.
Go to Step 1
System OK
6–59
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0659 Actuator Supply Voltage 1 (HSD1) High
END VIEW OF
80-WAY CONNECTOR
END VIEW OF
20-WAY CONNECTOR
1
6
7
10
11
14
15
20
61
80
41
60
21
40
1
20
TRANSMISSION
TRANSID
HSD1
PCS4
PCS6
MAIN MOD
TCM
WIRE 176
20
WIRE 111
1
WIRE 155
2
WIRE 178
7
WIRE 174
8
76
11
TRANSID
HSD1
ANALOG
INTERFACE
55
78
V BATTERY
74
V09066.00.00
Circuit Description
High Side Driver 1 (HSD1) supplies battery voltage to the Main Mod, PCS4 and PCS6 solenoids via wire 111.
HSD1 is continuously ON during normal operation except during brief circuit tests. The TCM regulates control
current to the solenoids by switching the appropriate Low Side Driver ON and OFF. DTC P0659 indicates the
TCM has detected greater than or equal to 6V in the HSD1 circuit when HSD1 is OFF during TCM initialization.
DTC P0659 could be caused by an open or short-to-battery in the high side wiring attached to HSD1 (wire 111).
Conditions for Running the DTC
•
The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater
than 9V and less than 32V (24V TCM).
•
HSD1 is commanded ON.
•
Engine speed greater than 200 rpm.
Conditions for Setting the DTC
DTC P0659 is set when the TCM detects a high voltage condition (> 6V) in the HSD1 circuit after two solenoids
indicate a failure.
6–60
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0659 Actuator Supply Voltage 1 (HSD1) High
Actions Taken When the DTC Sets
When DTC P0659 is active, the following conditions will occur:
•
The CHECK TRANS light illuminates.
•
DTC is stored in TCM history.
•
The TCM commands OFF all solenoids (SOL OFF). The shift selector position and hydraulic state of latch
valves determines range attained.
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
•
You may have to drive the vehicle in order to experience a fault. Use the data obtained from failure records to
determine transmission range and/or certain vehicle operating variables such as temperature, run time, etc. This
data can be useful in reproducing the failure mode when DTC was set.
•
Inspect the wiring for poor electrical connections at the TCM and transmission connector. Look for the
following conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
•
Inspect OEM wiring harness routing, look for possible contact points where chafing could occur leading to an
open or short circuit condition. Moving parts on the vehicle could be contacting the harness; this includes
parking brake drum, suspension components, etc.
•
When diagnosing for an intermittent short or open, massage the wiring harness while watching the test
equipment for a change.
Test Description
This DTC requires the use of the J 47275 TCM Breakout and J 47279 Transmission Breakout. The numbers below
refer to step numbers on the diagnostic table.
2. This step tests for the proper ignition voltage.
3. This step tests for an active DTC.
4. This step tests for an excessive voltage drop (open) in wire 111 of the OEM harness.
5. This step tests for a wire-to-wire short, or short-to-ground in the wire 111 of the OEM chassis harness.
7. This step tests for wiring defects in the transmission internal harness.
Copyright © 2005 General Motors Corp.
6–61
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0659 Actuator Supply Voltage 1 (HSD1) High
Step
1
2
3
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
1. Install the Allison DOC™ For PC–Service Tool. 9–18V (12V TCM)
18–32V (24V TCM)
2. Start the engine.
3. Record the failure records.
4. Monitor ignition voltage.
Is the voltage within the specified values?
1. Clear the DTC.
2. Start the engine and test drive the vehicle.
3. Attempt to duplicate the same conditions
observed in the failure records (range attained,
temperature, etc.).
Yes
Go to Step 2
Go to Step 3
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Resolve voltage
problem
Go to Step 4
Go to
Diagnostic Aids
Go to Step 6
Go to Step 5
NOTE: This DTC is intended to detect an open or
short-to-battery condition in the HSD1 electrical
circuit.
4
Did DTC P0659 return?
1. Turn OFF ignition.
2. Install J 47275 TCM Breakout to the TCM
80-way connector.
3. Install J 47279 Transmission Breakout at the
transmission 20-way connector.
4. Turn ON the ignition. Leave the engine OFF.
5. Using Allison DOC™ For PC–Service Tool, enter
Solenoid Test mode and command PCS4 ON.
6. Determine the voltage drop in the HSD1 circuit
as follows:
• At J 47275-1 TCM Overlay, measure voltage
between pin 11 and an isolated ground.
• At J 47279-1 Transmission Overlay, measure
voltage between pin 1 and an isolated ground.
• Subtract the two voltage measurements to
obtain the voltage drop in the circuit.
NOTE: A voltage drop of more than 0.5V indicates
an excessive voltage loss in the OEM harness.
Did the high-side voltage drop exceed 0.5VDC?
6–62
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0659 Actuator Supply Voltage 1 (HSD1) High (cont’d)
Step
5
6
7
8
9
Action
1. Turn OFF the ignition.
2. Disconnect the TCM from J 47275 TCM
Breakout. Leave the OEM-side connected.
3. Disconnect the OEM-side of the 20-way
connector from the J 47279 Transmission
Breakout. Leave the transmission-side connected.
4. Inspect the routing of wire 111 in the chassis
harness between the TCM and the transmission
connector.
5. At J 47275-1 TCM Overlay, test for wire-to-wire
shorts between pin 11 and all other pins in the
80-way connector.
Were any wire-to-wire shorts found?
NOTE: The vehicle OEM has responsibility for all
external wiring harnesses and vehicle input/output
switch repair. Harness and switch repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Coordinate with the vehicle OEM to repair or
replace the vehicle wiring or switch.
Is the repair complete?
1. Turn OFF the ignition.
2. Verify that the J 47279 Transmission Breakout is
installed at the transmission 20-way connector
and the OEM-side is disconnected.
3. Using DVOM at J 47279-1 Transmission
Overlay, test for wire-to-wire shorts between
pin 1 and all other pins in the 20-way connector.
NOTE: The resistance value between pins 1 and 2,
between pins 1 and 7 (7-speed models), and between
pins 1 and 8 will read normal solenoid resistance.
The resistance value between pins 1 and the pin 20
(TID wire) will read 0 Ohms.
Were any wire-to-wire shorts found?
1. Remove the hydraulic control module assembly.
2. Repair or replace the internal wiring harness.
Is the repair complete?
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
Value(s)
Yes
Go to Step 6
No
Go to Step 7
Go to Step 10
Go to Step 8
Go to Step 9
Go to Step 10
Go to Step 10
Refer to TCM diagnostic procedure, Section 3–6.
Is Section 3–6 complete?
10
In order to verify your repair:
1. Clear the DTC.
2. Drive the vehicle under conditions noted in
failure records.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Begin the
diagnosis again.
Go to Step 1
System OK
6–63
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0702 Transmission Control System Electrical (TransID)
END VIEW OF
80-WAY CONNECTOR
END VIEW OF
20-WAY CONNECTOR
1
6
7
10
11
14
15
20
61
80
41
60
21
40
1
20
TRANSMISSION
TRANSID
HSD1
PCS4
PCS6
MAIN MOD
TCM
WIRE 176
20
WIRE 111
1
WIRE 155
2
WIRE 178
7
WIRE 174
8
76
11
TRANSID
HSD1
ANALOG
INTERFACE
55
78
V BATTERY
74
V09066.00.00
Circuit Description
The TransID (TID) feature enables the TCM to recognize various transmission hardware configurations and select
an appropriate software calibration. The TCM senses the transmission configuration using TID wire 176. In initial
versions of Allison 4th Generation Controls, wire 176 is connected to High Side Driver 1 (HSD1) via wire 111, in
the internal wiring harness. HSD1 supplies the Main Mod solenoid, PCS4, and PCS6. This wiring configuration is
designated TID A.
Conditions for Running the DTC
The test is enabled by the TCM calibration.
Conditions for Setting the DTC
DTC P0702 sets if the TCM is unable to determine the TransID level of the transmission.
Actions Taken When the DTC Sets
•
•
•
The CHECK TRANS light illuminates.
DTC is stored in TCM history.
The TCM uses a TID A calibration.
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
6–64
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
Diagnostic Aids
DTC P0702 could be caused by an open circuit condition in wire 176 in the chassis harness.
Test Description
This DTC requires the use of the J 47275 TCM Breakout. The numbers below refer to step numbers on the
diagnostic table.
2. This step tests the TID circuit in the internal wiring harness.
4. This step tests the TID in the external wiring harness.
DTC P0702 Transmission Control System Electrical (TransID)
Step
1
2
3
4
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
1. Turn OFF the ignition.
2. Disconnect the transmission 20-way connector.
3. Using a digital multimeter (DVOM), test for
continuity (0 Ohms) between pin 20 (TID wire
176) and pin 1 in the transmission 20-way
connector.
4. Consult Table 6–7, at the end of this DTC, to
determine the TransID configuration of the
transmission.
5. Compare the continuity test results from sub-step
3 with the TID in the transmission bill of material
or build history.
Does the continuity test results in sub-step 3 agree
with the TransID of the transmission?
Repair or replace the internal transmission harness.
Is the repair complete?
1. Turn OFF ignition.
2. Disconnect the 80-way connector at the TCM.
3. Install the OEM-side 80-way connector to
J 47275 TCM Breakout. Leave the TCM
disconnected.
4. Reconnect the transmission 20-way connector.
5. Using a digital multimeter (DVOM), test for
continuity (0 Ohms) between pin 76 (TID wire)
and pin 11 in the 80-way connector.
6. Consult Table 6–8, at the end of this DTC, to
determine the TransID configuration of the
transmission.
7. Compare the continuity test results from substep 5 with the TID in the transmission bill of
material or build history.
Does the continuity test results in sub-step 5 agree
with the TransID of the transmission?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 2
Go to Step 4
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Go to Step 3
Go to Step 8
Go to Step 6
Go to Step 5
6–65
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0702 Transmission Control System Electrical (TransID) (cont’d)
Step
5
6
7
8
Action
NOTE: The vehicle OEM has responsibility for all
external wiring harnesses and vehicle input/output
switch repair. Harness and switch repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Value(s)
Coordinate with the vehicle OEM to repair or
replace the vehicle wiring.
Is the repair complete?
1. Reset Autodetect using Allison DOC™ For PC–
Service Tool.
2. Monitor “TransID Level Used” on Allison
DOC™ For PC–Service Tool.
3. Compare the TransID level indicated on Allison
DOC™ For PC–Service Tool to the actual
TransID level of the transmission.
Did the TCM detect the correct TID level?
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
Refer to TCM diagnostic procedure, Section 3–6.
Is Section 3–6 complete?
In order to verify your repair:
1. Clear the DTC.
2. Using Allison DOC™ For PC–Service Tool, reset
Autodetect.
3. Verify the TCM detects the correct TransID level.
Did the DTC return?
Yes
Go to Step 8
No
Go to Step 8
Go to Step 7
Go to Step 8
Begin the
diagnosis again.
Go to Step 1
Table 6–7.
Wire 176 will be connected to the following wire in the
transmission internal harness:
TID
A
Pin 20 connected to ...
Pin 1 (wire 111)
B
TBD
C
TBD
Table 6–8.
Wire 176 will be connected to the following wire via the
transmission internal harness:
TID
A
B
6–66
Pin 76 connected to ...
Pin 11 (wire 111)
TBD
Copyright © 2005 General Motors Corp.
System OK
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0703 Brake Switch Circuit Malfunction
END VIEW OF
80-WAY CONNECTOR
61
80
41
60
21
40
1
20
SERVICE BRAKE
SWITCH
ABS ACTIVATION VIA
J1939 LINK
62
SAE J1939
VEHICLE COMMUNICATION
INTERFACE
TCM
See appropriate
“Installation Schematic”
installation drawing for
wire and pin numbers.
OPTIONAL
CUSTOMER-FURNISHED
VEHICLE INTERFACE
WIRING CONNECTOR
3
TCM
WIRE 162 SERVICE
BRAKE STATUS
WIRE 103
SIGNAL RETURN
OPTIONAL
CUSTOMER-FURNISHED
VEHICLE INTERFACE
WIRING CONNECTOR
ALL ITEMS SHOWN,
EXCEPT TCM,
ARE CUSTOMER-FURNISHED
N.O.
COM N.C.
MAY BE MECHANICAL SWITCH.
IF VEHICLE IS EQUIPPED WITH
AIR BRAKES, THIS SWITCH
SHOULD CLOSE AT 2–5 PSI.
ALL ITEMS SHOWN,
EXCEPT TCM, ARE
CUSTOMER-FURNISHED
V09144.00.00
Circuit Description
The Transmission Control Module (TCM) can be calibrated to receive a service brake status input from either an
analog input wire or the digital data link. A mechanical switch attached to the brake pedal sends a signal to either
the TCM directly or to another electronic controller in the vehicle. When another controller is used, the TCM
receives service brake status as a digital message over the vehicle’s communications data link.
Conditions for Running the DTC
•
The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater
than 9V and less than 32V (24V TCM).
•
The components are powered and engine speed is greater than 200 rpm and less than 7500 rpm for 5 seconds.
Conditions for Setting the DTC
DTC P0703 sets if the TCM is calibrated to receive the service brake status signal and either of the following
conditions is met:
•
The TCM senses three acceleration events with service brake signal ON.
•
The TCM senses three deceleration events with service brake signal OFF.
Copyright © 2005 General Motors Corp.
6–67
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0703 Brake Switch Circuit Malfunction
Actions Taken When the DTC Sets
When DTC P0703 is active, the following conditions will occur:
•
•
•
•
The TCM does not illuminate the CHECK TRANS light.
DTC is stored in TCM history.
TCM inhibits Neutral to Drive shifts for refuse packer.
TCM inhibits Retarder operation if a Throttle Position Sensor (TPS) code is also active.
Conditions for Clearing DTC/CHECK TRANS Light
The Allison DOC For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
• When analog input wires are used, the service brake status input is active when a pressure switch is closed to
complete the circuit between wire 162 and signal return wire 103. If a data link is used, the TCM receives
“service brake status” as part of J1939 message parameter PGN 65265, Cruise Control/Vehicle Speed (CCVS).
•
•
•
DTC P0703 indicates the TCM has detected service brake status ON for 3 acceleration events or service brake
status OFF for 3 deceleration events. The code can be caused by:
— Faulty wiring
— Faulty connections to the service brake switch
— A faulty service brake switch
— Another controller improperly broadcasting service brake status on the data link when the brake switch is
not installed or operating
— A faulty TCM.
Inspect the wiring for poor electrical connections at the TCM and service brake switch. Look for the following
conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
J1939 service brake status can be read on Allison DOC™ For PC–Service Tool. Monitor data link
communications using Data Bus Viewer.
Test Description
This DTC requires the use of the J 47275 TCM Breakout. The numbers below refer to step numbers on the
diagnostic table.
2.
4.
5.
6.
7.
This step tests for an active DTC.
This step tests for status of analog input wire 162.
This step determines if service brake status is being communicated by a data link message.
This step tests for shorts-to-ground in wire 162.
This step tests for proper service brake switch function.
9. This step observes service brake switch status on the digital data link.
6–68
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0703 Brake Switch Circuit Malfunction
Step
1
2
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
1.
2.
3.
4.
Value(s)
Install the Allison DOC™ For PC–Service Tool.
Start the engine.
Record the failure records.
Clear the DTC and drive the vehicle. Attempt to
duplicate same operating conditions observed in
failure records.
Yes
Go to Step 2
Go to Step 3
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Go to
Diagnostic Aids
NOTE: This DTC indicates that the service brake
signal is present for more than three acceleration/
deceleration events.
3
4
5
6
7
Did DTC P0703 return?
Inspect vehicle for analog input wire 162.
Is analog input wire 162 present?
1. Turn ON the ignition.
2. Using Allison DOC™ For PC–Service Tool,
observe status of Service Brake input wire 162.
Does wire 162 go ON when brake pedal is depressed
and go OFF when brake pedal is released?
Using Allison DOC™ For PC–Service Tool, observe
status of service brake.
NOTE: If service brake status is ON while the
service brake input wire 162 is OFF, the TCM is
receiving a “brake switch status” message via the
data link.
Is the service brake status ON when wire 162 is
OFF?
1. Turn OFF the ignition.
2. Disconnect the TCM 80-way connector.
3. Install the OEM-side of the 80-way connector to
J 47275 TCM Breakout. Leave the TCM
disconnected.
4. Check for short-to-ground on wire 162.
Were any shorts or wiring defects found?
1. Turn OFF the ignition.
2. Using a DVOM, check for continuity when
switch is depressed and no continuity when
switch is released.
Does the switch close when depressed and open
when released?
Copyright © 2005 General Motors Corp.
Go to Step 4
Go to Step 9
Go to Step 5
Go to Step 6
Go to Step 9
Go to
Diagnostic Aids
Go to Step 8
Go to Step 7
Go to Step 9
Go to Step 8
6–69
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0703 Brake Switch Circuit Malfunction (cont’d)
Step
8
9
10
11
6–70
Action
NOTE: The vehicle OEM has responsibility for all
external wiring harnesses and vehicle input/output
switch repair. Harness and switch repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Value(s)
Coordinate with the vehicle OEM to repair or
replace the vehicle wiring or switch.
Is the repair complete?
1. Turn OFF the ignition.
2. Connect the 80-way connector, if removed in
Step 6.
3. Install Allison DOC™ For PC–Service Tool.
4. Turn ON the ignition.
5. Using Allison DOC™ For PC–Service Tool Data
Bus Viewer, observe status of Service Brake
Switch. Consult Allison DOC™ For PC–Service
Tool User’s Guide (GN3433EN) for instructions
on using Data Bus Viewer.
On Data Bus Viewer, does brake switch show ON
when brake pedal is depressed and OFF when brake
pedal is released?
NOTE: Allison Transmission is not responsible for
data link messages that originate in other
transmission controllers. Repairs not associated
with the transmission controller are not covered by
Allison Transmission warranty.
Coordinate with the vehicle or engine OEM to
correct the cause of the inconsistent service brake
switch status message.
Is the repair complete?
In order to verify your repair:
1. Clear the DTC.
2. Use Allison DOC™ For PC–Service Tool to
monitor service brake status.
3. Drive the vehicle under conditions noted in
failure records.
4. Confirm with the service tool in the test passed
section that the diagnostic test was run.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 11
No
Go to
Diagnostic Aids
Go to Step 10
Go to Step 11
Begin the
diagnosis again.
Go to Step 1
System OK
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0708 Transmission Range Sensor Circuit High Input
END VIEW OF
20-WAY CONNECTOR
K
D
END VIEW OF
80-WAY CONNECTOR
S
W
A
E
61
80
41
60
21
40
1
20
T
L
D N R
1
2
3
D N R
TCM
A
B
C
E
L
P
STRIP SHIFT
SELECTOR
SS-1
WIRE 173
SS-2
WIRE 153
SS-4
WIRE 114
SS-P
WIRE 178
LAMP
GROUND
DIGITAL
GROUND
WIRE 150
WIRE 103
73
53
14
DIGITAL
INTERFACE
38
50
3
R
V09229.00.00
Circuit Description
The 3000 and 4000 Product Family transmission control module (TCM) can receive input from a strip-type shift
selector. This type of shift selector communicates with the TCM via 4-bit parallel data wires. The strip shift
selector button position determines the switch state (low or high voltage) of each parallel data wire. The TCM
interprets each particular combination of switch states into a specific range selection, i.e. Reverse, Neutral, and
DRIVE. The TCM sets a DTC P0708 if the switch state of the four parallel data wires does not agree with a valid
switch combination.
Conditions for Running the DTC
•
The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater
than 9V and less than 32V (24V TCM).
•
The components are powered and engine speed is greater than 200 rpm and less than 7500 rpm.
Copyright © 2005 General Motors Corp.
6–71
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
Conditions for Setting the DTC
DTC PO708 sets when the TCM detects an invalid parallel data message from a strip-type shift selector.
Actions Taken When the DTC Sets
When DTC P0708 is active, the following conditions will occur:
•
The CHECK TRANS light illuminates.
•
DTC is stored in TCM history.
•
The TCM ignores invalid strip shift selector inputs.
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycle without failure.
Diagnostic Aids
•
You may have to drive the vehicle in order to experience a fault. Use the data obtained from failure records to
determine transmission range and/or certain vehicle operating variables such as temperature, run time, etc. This
data can be useful in reproducing the failure mode when DTC was set.
•
Inspect the wiring for poor electrical connections at the TCM and transmission connector. Look for the
following conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
•
Inspect OEM wiring harness routing, look for possible contact points where chafing could occur leading to an
open or short circuit condition. Moving parts on the vehicle could be contacting the harness; this includes
parking brake drum, suspension components, etc.
•
When diagnosing for an intermittent short or open, massage the wiring harness while watching the test
equipment for a change.
Test Description
This DTC requires the use of the J 47275 TCM Breakout. The numbers below refer to step numbers on the
diagnostic table.
2. This step tests for the proper function of the strip shift selector.
3. This step measures the switch states (low or high voltage) for each button position.
4. This step tests for wiring defects in the OEM wiring harness.
6–72
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0708 Transmission Range Sensor Circuit High Input
Step
1
2
3
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
1.
2.
3.
4.
Install the Allison DOC™ For PC–Service Tool.
Turn ON the ignition. Leave the engine OFF.
Record the failure records.
Using Allison DOC™ For PC–Service Tool,
monitor “STRIP SELECTOR OUTPUT
PATTERN” for the affected strip shift selector.
5. Toggle through each button position while
observing the Allison DOC™ For PC–Service
Tool display.
Does “STRIP SELECTOR OUTPUT PATTERN”
status match the actual shift selector button position?
1. Turn OFF the ignition.
Refer to Strip Shift
2. Install J 47275 TCM Breakout between the OEM Selector Parallel
and TCM 80-way connectors.
Data Table 6–9
3. Turn ON ignition. Leave engine OFF.
4. Using a DVOM at J 47275-1 TCM Overlay,
determine the state (High or Low) of each parallel
data wire by measuring the following voltages.
Record voltages <1V as Low and voltages >3V as
High.
• Between pin 73 (SS-1) and isolated ground
• Between pin 53 (SS-2) and isolated ground
• Between pin 14 (SS-4) and isolated ground
• Between pin 38 (SS-P) and isolated ground
5. Toggle through each strip selector button position
that displays a faulty output pattern and measure
voltages at pins listed in sub-step 4 above.
6. Compare the switch states (low or high voltage)
obtained in sub-steps 4 and 5 with the Strip Shift
Selector Parallel data in Table 6–9.
7. Note if any wire is not in the proper switch state.
Do the switch states (low or high voltage) match the
valid switch states shown in Table 6–9 for all button
positions?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 2
Go to
Diagnostic Aids
Go to
Diagnostic Aids
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Go to Step 3
Go to Step 4
6–73
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0708 Transmission Range Sensor Circuit High Input (cont’d)
Step
4
5
6
7
Action
NOTE: Review Section 4—Wire Test Procedures
before performing the following steps.
1. Turn OFF the ignition.
2. Disconnect the TCM from the J 47275 TCM
Breakout. Leave the OEM-side connected.
3. Disconnect the strip shift selector.
4. Physically inspect the wiring between the striptype shift selector and the TCM.
5. Using a DVOM at magnetic overlay, test for
opens, wire-to-wire shorts, and shorts-to-ground
for any wire found to be in the incorrect switch
state (low or high voltage) in Step 3 above.
Were any wiring defects found?
NOTE: The vehicle OEM has responsibility for all
external harness repair. Harness repairs performed
by Allison Transmission distributors and dealers
are not covered bt Allison Transmission warranty.
Value(s)
Yes
Go to Step 5
No
Go to Step 6
Go to Step 7
Coordinate with the vehicle OEM to repair or
replace the vehicle wiring.
Is the repair complete?
Replace the shift selector.
Is the replacement complete?
In order to verify your repair:
1. Clear the DTC.
2. Drive the vehicle under conditions noted in
failure records.
Did the DTC return?
Go to Step 7
Begin the
diagnosis again.
Go to Step 1
System OK
Table 6–9.
SS-1
Button
Sel Out
173
R
REVERSE
Low**
N
NEUTRAL
Low**
D
DRIVE-A
Low**
3*
DRIVE-B
High***
2*
DRIVE-C
High***
1*
DRIVE-D
High***
*Six-button shift selectors only
**Low is <1V
***High is >3V
6–74
Wire Number
SS-2
SS-4
153
114
Low**
Low**
High***
High***
Low**
High***
Low**
High***
Low**
Low**
High***
Low**
Copyright © 2005 General Motors Corp.
SS-Parity
138
High***
High***
Low**
High***
Low**
High***
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P070C Transmission Fluid Level Sensor Circuit—Low Input
END VIEW OF
20-WAY CONNECTOR
END VIEW OF
80-WAY CONNECTOR
1
6
7
10
11
14
15
20
61
80
41
60
21
40
1
20
TO RETARDER
CONTROL DEVICES
RETARDER
REQUEST SENSOR
(RESISTANCE
MODULE)
A
PWM
THROTTLE
SOURCE
B
C
TCM
THROTTLE
POSITION
SENSOR (TPS)
OR
ELECTRONIC
BRAKING (EBS)
RTDR PRESSURE
SENSOR
WIRE 156
WIRE 112
C
WIRE 144
B
WIRE 158
A
RETARDER TEMP
ENGINE TEMP
TRANSMISSION
ANALOG RETURN
OIL LEVEL
HALL
A
C
EFFECT
B
SUMP TEMP
19
16
15
18
PS1
NC*
* NORMALLY
3
WIRE 175
WIRE 135
56
RETARDER REQUEST SIGNAL
12
5V SENSOR VOLTAGE
44
THROTTLE POSITION OR
RTDR PRESSURE SIGNAL
58
ANALOG RETURN
75
RETARDER TEMP
35
ENGINE WATER TEMP
16
OIL LEVEL SENSOR
54
SUMP TEMP
77
PS1 DIAGNOSTIC
PRESSURE SWITCH
WIRE 158
WIRE 112
WIRE 116
WIRE 154
WIRE 177
CLOSED
V09069.01.00
Copyright © 2005 General Motors Corp.
6–75
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P070C Transmission Fluid Level Sensor Circuit—Low Input
Circuit Description
The transmission control module (TCM) can be calibrated to receive a transmission fluid level signal from an oil
level sensor (OLS). The TCM is connected to the OLS by:
•
a reference voltage wire,
•
retarder request signal wire, and
•
analog ground wire.
The TCM provides a 5V reference voltage to the OLS. A microprocessor in the OLS produces a signal voltage that
is proportional to the level of fluid in the transmission sump. The TCM interprets this voltage as transmission fluid
level.
Conditions for Running the DTC
Engine speed is greater than 1500 rpm.
Conditions for Setting the DTC
DTC P070C sets if the TCM is calibrated to receive the OLS signal, and the signal voltage is less than 0.1V for six
consecutive samples.
Actions Taken When the DTC Sets
When DTC P070C is active, the following conditions will occur:
•
The TCM does not illuminate the CHECK TRANS light.
•
DTC is stored in TCM history.
Conditions for Clearing the DTC/CHECK TRANS Light
•
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history.
•
The TCM automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles
without failure.
Diagnostic Aids
•
DTC P070C indicates the TCM has detected a voltage signal from the OLS in the low error zone. The code can
be caused by:
— Extremely low transmission fluid level
— Faulty external wiring harness
— Faulty connections to the OLS
— Faulty internal wiring harness
— Faulty OLS
— Faulty TCM.
•
DTC P070C can be caused by an open or short-to-ground in either the 5V reference wire 112 or transmission
fluid level signal wire 116. The OLS shares the common 5V reference voltage wire with the optional retarder
request sensor and throttle position sensor (TPS). An open or short-to-ground in the common 5V reference
wire causes a “sensor failed low” code for the other devices as well. An open or short-to ground on wire 116
will cause a DTC P070C only.
6–76
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
•
Inspect the wiring for poor electrical connections at the TCM. Look for the following conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
Test Description
This DTC requires the use of the J 47275 TCM Breakout. The numbers below refer to step numbers on the
diagnostic table.
2. This step tests for proper transmission fluid level.
3. This step tests for an active DTC.
4. This step tests for proper 5V reference voltage to OLS.
5. This step tests for opens or short-to-ground on wire 112.
6. This step tests for TCM function and OLS signal circuit integrity.
DTC P070C Transmission Fluid Level Sensor Circuit—Low Input
Step
1
2
3
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
Consult mechanic’s tips and perform a manual fluid
check procedure. Adjust as necessary.
Is the transmission fluid level correct?
1. Install the Allison DOC™ For PC–Service Tool.
2. Start the engine.
3. Record the failure records.
4. Clear the DTC. Attempt to duplicate same
operating conditions observed in failure records.
Yes
Go to Step 2
Go to Step 3
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Adjust as
necessary.
Go to Step 3
Go to Step 4
Go to
Diagnostic Aids
Go to Step 6
Go to Step 5
NOTE: This DTC indicates the OLS signal is below
a set voltage for a set number of samples. It may
also indicate an open or short-to-ground in either
the 5V reference wire 112 or OLS signal wire 116.
4
Did DTC P070C return?
1. Turn OFF the ignition.
2. Disconnect the external wiring harness from the
20-way transmission connector.
3. Turn ON the ignition.
4. Using a DVOM, measure the voltage between pin
16 (5V reference wire 112) and pin 19 (analog
return wire 158) at the external harness 20-way
connector.
Is the voltage within specification?
4.64–5.36V
Copyright © 2005 General Motors Corp.
6–77
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P070C Transmission Fluid Level Sensor Circuit—Low Input (cont’d)
Step
5
6
7
8
9
10
6–78
Action
1. Turn OFF the ignition.
2. Inspect the routing of 5V reference wire 112 and
analog return wire 158 between the TCM and
OLS sensor.
3. Disconnect the 80-way connector from the TCM.
4. Install the OEM-side of the 80-way connector to
the J 47275 TCM Breakout. Leave the TCM
disconnected.
5. Disconnect the TPS and RMR, if installed.
6. Test for opens and shorts-to-ground on wire 112.
Was chafing or wire damage found?
1. Turn OFF the ignition.
2. Connect the 80-way connector.
3. Install the Allison DOC™ For PC–Service Tool.
4. Turn ON the ignition.
5. Verify the transmission 20-way connector is
disconnected.
6. Observe OLS voltage on Allison DOC™ For PC–
Service Tool while jumpering between pin 16 (5V
reference wire 112) and pin 15 (OLS signal wire
116) in the external harness 20-way connector.
Is the voltage within specifications?
1. Turn OFF the ignition.
2. Inspect the routing of the OLS signal wire 116
between the TCM and OLS.
3. Disconnect the 80-way connector from the TCM.
4. Connect the OEM-side of the 80-way connector
to the J 47275 TCM Breakout. Leave the
TCM-side disconnected.
5. Test for opens and shorts-to-ground on wire 116.
Was chafing or wire damage found?
NOTE: The vehicle OEM has responsibility for all
external wiring harness repairs. Harness repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Value(s)
Yes
Go to Step 8
No
Go to Step 6
4.64–5.36V
Go to Step 9
Go to Step 7
Go to Step 8
Go to Step 16
Coordinate with the vehicle OEM to repair or
replace the vehicle wiring.
Is the repair complete?
Inspect the transmission 20-way connector pins 15,
16, and 19 for loose or out-of-position terminals.
Were any loose or out-of-position terminals founds?
Repair or replace any defective terminals.
Is the repair complete?
Copyright © 2005 General Motors Corp.
Go to Step 17
Go to Step 10
Go to Step 17
Go to Step 11
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P070C Transmission Fluid Level Sensor Circuit—Low Input (cont’d)
Step
11
12
13
14
15
16
17
Action
1. Consult appropriate transmission service manual
and remove the control module from the
transmission.
2. Remove OLS from channel plate.
3. Connect the external harness at the 20-way
connector.
4. Install the Allison DOC™ For PC–Service Tool.
5. Turn ON the ignition. Leave the ignition OFF.
6. Invert the OLS and observe OLS voltage.
Does Allison DOC™ For PC–Service Tool OLS
voltage jump to 5V?
1. Inspect internal wiring harness wires 112, 116,
and 158.
2. Test for opens and shorts-to-ground in wires 112
and 116 in the internal wiring harness.
Were there any wiring defects?
Repair or replace the internal wiring harness.
Is the repair complete?
Replace the OLS.
Is the replacement complete?
Install the control module to the transmission if
removed in Step 11.
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
Value(s)
4.64–5.36V
Refer to TCM diagnostic procedure, Section 3–6.
Is Section 3–6 complete?
In order to verify your repair:
1. Clear the DTC.
2. Use Allison DOC™ For PC–Service Tool to
monitor OLS level and voltage.
3. Confirm with Allison DOC™ For PC–Service
Tool in the test passed section that the diagnostic
test was run.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 15
No
Go to Step 12
Go to Step 13
Go to Step 14
Go to Step 15
Go to Step 15
Go to Step 17
Go to Step 17
Begin the
diagnosis again.
Go to Step 1
System OK
6–79
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P070D Transmission Fluid Level Sensor Circuit—High Input
END VIEW OF
20-WAY CONNECTOR
END VIEW OF
80-WAY CONNECTOR
1
6
7
10
11
14
15
20
61
80
41
60
21
40
1
20
TO RETARDER
CONTROL DEVICES
RETARDER
REQUEST SENSOR
(RESISTANCE
MODULE)
A
PWM
THROTTLE
SOURCE
B
C
TCM
THROTTLE
POSITION
SENSOR (TPS)
OR
ELECTRONIC
BRAKING (EBS)
RTDR PRESSURE
SENSOR
WIRE 156
WIRE 112
C
WIRE 144
B
WIRE 158
A
RETARDER TEMP
ENGINE TEMP
WIRE 175
WIRE 135
TRANSMISSION
ANALOG RETURN
OIL LEVEL
HALL
A
C
EFFECT
B
SUMP TEMP
19
16
15
18
PS1
NC*
* NORMALLY
3
56
RETARDER REQUEST SIGNAL
12
5V SENSOR VOLTAGE
44
THROTTLE POSITION OR
RTDR PRESSURE SIGNAL
58
ANALOG RETURN
75
RETARDER TEMP
35
ENGINE WATER TEMP
16
OIL LEVEL SENSOR
54
SUMP TEMP
77
PS1 DIAGNOSTIC
PRESSURE SWITCH
WIRE 158
WIRE 112
WIRE 116
WIRE 154
WIRE 177
CLOSED
V09069.01.00
6–80
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P070D Transmission Fluid Level Sensor Circuit—High Input
Circuit Description
The Transmission Control Module (TCM) can be calibrated to receive a transmission fluid level signal from an oil
level sensor (OLS). The TCM is connected to the OLS by three wires: 1) a reference voltage, 2) transmission fluid
level signal, and 3) analog ground. The TCM provides a 5V reference voltage to the OLS. A microprocessor in the
OLS produces a signal voltage that proportional to level of fluid in the transmission sump. The TCM interprets this
voltage as transmission fluid level.
Conditions for Running the DTC
Engine speed is greater than 1500 rpm.
Conditions for Setting the DTC
DTC P070D sets if the TCM is calibrated to receive the OLS signal, and the signal voltage is greater than 5.0V for
6 consecutive samples.
Actions Taken When the DTC Sets
When DTC P070D is active, the following conditions will occur:
• The TCM does not illuminate the CHECK TRANS light.
• DTC is stored in TCM history.
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
• DTC P070D indicates the TCM has detected a voltage signal from the OLS in the high error zone. The code
can be caused by:
— Extremely high transmission fluid level
— Faulty external wiring harness
— Faulty connections to the OLS
— Faulty internal wiring harness
— A faulty OLS
— A faulty TCM.
• DTC P070D can be caused by a short-to-battery on the 5V reference wire 112 or OLS signal wire 116. DTC
P070D can also be caused by an open in the analog return wire 158. The OLS shares a common 5V reference
voltage wire 112 with the optional retarder request sensor and throttle position sensor (TPS). A short-to-battery
on the 5V reference wire or an open in the analog return wire causes a “sensor failed high” code for the other
devices as well. A short-to-battery on the OLS signal wire causes a DTC P070D only.
•
Inspect the wiring for poor electrical connections at the TCM. Look for the following conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
Copyright © 2005 General Motors Corp.
6–81
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
Test Description
This DTC requires the use of the J 47275 TCM Breakout. The numbers below refer to step numbers on the
diagnostic table.
2. This step tests for proper transmission fluid level.
3. This step tests for an active DTC.
4. This step tests for proper 5V reference voltage to OLS.
5. This step tests for shorts-to-battery on wire 112 and open on wire 158.
7. This step tests for shorts-to-battery on wire 116.
9. This step tests for loose or out-of-position terminals in 20-way connector.
11. This step tests OLS functionality.
12. This step tests for a defective internal wiring harness.
DTC P070D Transmission Fluid Level Sensor Circuit—High Input
Step
1
2
3
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
Consult mechanic’s tips and perform a manual fluid
check procedure. Adjust as necessary.
Is the transmission fluid level correct?
1. Install the Allison DOC™ For PC–Service Tool.
2. Start the engine.
3. Record the failure records.
4. Clear the DTC. Attempt to duplicate same
operating conditions observed in failure records.
Yes
Go to Step 2
Go to Step 3
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Adjust as
necessary.
Go to Step 3
Go to Step 4
Go to
Diagnostic Aids
Go to Step 6
Go to Step 5
NOTE: This DTC indicates the OLS signal is above
a set voltage for a set number of samples. It may
also indicate a short-to-battery in either the 5V
reference wire 112 or OLS signal wire 116, or an
open in the analog return wire 158.
4
6–82
Did DTC P070D return?
1. Turn OFF the ignition.
2. Disconnect the external wiring harness from the
20-way transmission connector.
3. Turn ON the ignition.
4. Using a DVOM, measure the voltage between
pin 16 (5V reference wire 112) and pin 19
(analog return wire 158) at the external harness
20-way connector.
Is the voltage within specification?
4.64–5.36V
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P070D Transmission Fluid Level Sensor Circuit—High Input (cont’d)
Step
5
6
7
8
9
10
Action
1. Turn OFF the ignition.
2. Inspect the routing of 5V reference wire 112 and
analog return wire 158 between the TCM and
OLS sensor.
3. Disconnect the 80-way connector from the TCM.
4. Install the OEM-side of the 80-way connector to
the J 47275 TCM Breakout. Leave the TCM
disconnected.
5. Disconnect the TPS and RMR, if installed.
6. Test for shorts-to-battery and pin-to-pin shorts on
wire 112.
7. Test for an open in wire 158.
Was chafing or wire damage found?
1.
2.
3.
4.
5.
Turn OFF the ignition.
Reconnect the TCM 80-way connector.
Install the Allison DOC™ For PC–Service Tool.
Turn ON the ignition.
Verify the transmission 20-way connector is
disconnected.
6. Observe OLS voltage on Allison DOC™ For PC–
Service Tool.
Is voltage approximately 0V?
1. Turn OFF the ignition.
2. Inspect the routing of the OLS signal wire 116
between the TCM and OLS.
3. Disconnect the 80-way connector from the TCM.
4. Install the OEM-side of the 80-way connector to
the J 47275 TCM Breakout. Leave the TCM
disconnected.
5. Test for shorts-to-battery and pin-to-pin shorts in
wire 116.
Was chafing or wire damage found?
NOTE: The vehicle OEM has responsibility for all
external wiring harness repairs. Harness repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Value(s)
Yes
Go to Step 8
No
Go to Step 6
<0.32V
Go to Step 9
Go to Step 7
Go to Step 8
Go to Step 16
Coordinate with the vehicle OEM to repair or
replace the vehicle wiring.
Is the repair complete?
Inspect the transmission 20-way connector pins 15,
16, and 19 for loose or out-of-position terminals.
Were any loose or out-of-position terminals found?
Repair or replace any defective terminals.
Is the repair complete?
Copyright © 2005 General Motors Corp.
Go to Step 17
Go to Step 10
Go to Step 11
Go to Step 17
6–83
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P070D Transmission Fluid Level Sensor Circuit—High Input (cont’d)
Step
11
12
13
14
15
16
17
6–84
Action
1. Consult appropriate transmission service manual
and remove the control module from the
transmission.
2. Remove OLS from channel plate.
3. Reconnect the external harness at the 20-way
connector.
4. Install the Allison DOC™ For PC–Service Tool.
5. Turn ON the ignition. Leave the engine OFF.
6. Remove the OLS up away from any transmission
fluid and observe OLS voltage on Allison DOC™
For PC–Service Tool.
Is the voltage in specification?
1. Inspect internal wiring harness wires 112, 116,
and 158.
2. Test for pin-to-pin shorts in wire 112 and 116 or
opens in wire 158 in the internal wiring harness.
Were there any wiring defects?
Repair or replace the internal wiring harness.
Is the repair complete?
Replace the OLS.
Is the replacement complete?
Reinstall the control module to the transmission if
removed in Step 11.
Is the reinstallation complete?
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
Value(s)
<0.32V
Refer to TCM diagnostic procedure, Section 3–6.
Is Section 3–6 complete?
In order to verify your repair:
1. Clear the DTC.
2. Use Allison DOC™ For PC–Service Tool to
monitor OLS level and voltage.
3. Confirm with the service tool in the test passed
section that the diagnostic test was run.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 15
No
Go to Step 12
Go to Step 13
Go to Step 14
Go to Step 15
Go to Step 15
Go to Step 17
Go to Step 17
Begin the
diagnosis again.
Go to Step 1
System OK
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0711 Transmission Fluid Temperature Sensor Circuit Performance
END VIEW OF
20-WAY CONNECTOR
END VIEW OF
80-WAY CONNECTOR
1
6
7
10
11
14
15
20
61
80
41
60
21
40
1
20
TO RETARDER
CONTROL DEVICES
RETARDER
REQUEST SENSOR
(RESISTANCE
MODULE)
A
PWM
THROTTLE
SOURCE
B
C
TCM
THROTTLE
POSITION
SENSOR (TPS)
OR
ELECTRONIC
BRAKING (EBS)
RTDR PRESSURE
SENSOR
WIRE 156
WIRE 112
C
WIRE 144
B
WIRE 158
A
RETARDER TEMP
ENGINE TEMP
WIRE 175
WIRE 135
TRANSMISSION
ANALOG RETURN
OIL LEVEL
HALL
A
C
EFFECT
B
SUMP TEMP
19
16
15
18
PS1
NC*
* NORMALLY
3
56
RETARDER REQUEST SIGNAL
12
5V SENSOR VOLTAGE
44
THROTTLE POSITION OR
RTDR PRESSURE SIGNAL
58
ANALOG RETURN
75
RETARDER TEMP
35
ENGINE WATER TEMP
16
OIL LEVEL SENSOR
54
SUMP TEMP
77
PS1 DIAGNOSTIC
PRESSURE SWITCH
WIRE 158
WIRE 112
WIRE 116
WIRE 154
WIRE 177
CLOSED
V09069.01.00
Copyright © 2005 General Motors Corp.
6–85
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0711 Transmission Fluid Temperature Sensor Circuit Performance
Circuit Description
The Transmission Fluid Temperature (TFT) sensor is incorporated into the internal wiring harness. The TFT sensor
is a thermistor that changes its resistance value based on the temperature of the transmission fluid. The
Transmission Control Module (TCM) supplies a 5V reference voltage signal to the TFT sensor and measures the
voltage drop in the circuit. When the transmission is cold, the sensor resistance is high and the TCM detects high
signal voltage. As the transmission fluid temperature warms to normal operating temperature, the resistance and the
signal voltage decrease. The TCM uses this information to control shift quality.
If the TCM detects the TFT sensor resistance has no change or an unrealistic change in a short amount of time, or
multiple changes within seconds, DTC P0711 sets.
Conditions for Running the DTC
• The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater
than 9V and less than 32V (24V TCM).
• The components are powered and engine speed is greater than 200 rpm and less than 7500 rpm for 5 seconds.
• Engine is running.
• A valid startup temperature is detected.
Conditions for Setting the DTC
One of the following conditions occur:
•
•
•
The TCM detects a temperature change that is under a calibration limit when compared to samples of the
minimum and maximum temperature values.
The TFT has an unrealistic temperature change of more than 10°C (50°F) for 10 occurrences.
The temperature from start-up changes by 40°C (104°F) or more within a duration of 6 or more seconds.
Actions Taken When the DTC Sets
When DTC P0711 is active, the following conditions will occur:
•
•
•
The CHECK TRANS light is illuminated.
DTC is stored in TCM history.
TCM uses calibration default for temperature values.
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
• Review Appendix A for diagnosing intermittent electrical fault conditions.
•
Inspect the wiring for poor electrical connections at the TCM and transmission connector. Look for the
following conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
6–86
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
•
When diagnosing for an intermittent short or open, massage the wiring harness while watching the test
equipment for a change.
•
You may have to drive the vehicle in order to experience a fault.
•
Transmission fluid temperature on Allison DOC™ For PC–Service Tool should rise steadily during warmup
cycles and then stabilize.
Test Description
This DTC requires the use of the J 47275 TCM Breakout and J 47279 Transmission Breakout. The numbers below
refer to step numbers on the diagnostic table.
2. This step tests for proper transmission fluid level and condition.
3. This step verifies which condition has set the DTC P0711.
4. This step tests for the proper 5V reference voltage at TCM with OEM harness connected.
5. This step tests for proper 5V reference voltage at TCM without OEM harness.
6. This step tests for wire-to-wire shorts, shorts-to-ground, or an open condition on wire 154.
7. This step tests for proper system circuit resistance value.
8. This step tests the resistance value of the internal harness and TFT sensor.
10. This step tests the resistance value of the internal TFT sensor.
DTC P0711 Transmission Fluid Temperature Sensor Circuit Performance
Step
1
2
3
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Perform the Fluid Check Procedure (refer to the
appropriate mechanic’s tips).
Is the transmission fluid level correct?
1. Install the Allison DOC™ For PC–Service Tool.
2. With the engine OFF, turn ON the ignition.
3. Record the failure record.
4. Clear the DTCs.
5. Monitor the TFT on Allison DOC™ For PC–
Service Tool.
6. Drive the vehicle and observe Allison DOC For
PC–Service Tool for one of the following
conditions:
• No Transmission temperature change.
• An unrealistic transmission temperature
change of greater than 1.5°C (2.7°F) in one
second.
Value(s)
Yes
Go to Step 2
Go to Step 3
1.5°°C (2.7°°F)
per second
Go to Step 4
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Go to Fluid Check
Procedure (refer to
mechanic’s tips)
Go to
Diagnostic Aids
Did either of the fail conditions occur?
Copyright © 2005 General Motors Corp.
6–87
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0711 Transmission Fluid Temperature Sensor Circuit Performance (cont’d)
Step
4
5
6
Action
Turn OFF the ignition.
Install J 47275 TCM Breakout at the TCM.
Disconnect the transmission 20-way connector.
Turn ON the ignition.
At J 47275-1 TCM Overlay, connect a DVOM.
Measure voltage between pin 54 and pin 58.
Is the voltage within the specified value?
1. Turn OFF the ignition.
2. Disconnect the 16-pin bypass connector on the
J 47275 TCM Breakout.
3. Turn ON the ignition.
4. Using a DVOM at J 47275-1 TCM Overlay,
measure voltage between pin 54 and pin 58.
Is the voltage within the specified value?
1. Turn OFF the ignition.
2. Disconnect the TCM from the J 47275 TCM
Breakout. Leave the OEM-side connected.
3. Disconnect the transmission 20-way connector, if
it was not disconnected in Step 4.
4. Reconnect the 16-pin bypass connector on
J 47275 TCM Breakout.
5. Using a DVOM at J 47275-1 TCM Overlay, test
for opens, pin-to-pin shorts, or shorts-to-ground
on wire 154.
Were any wiring defects found?
1.
2.
3.
4.
5.
Value(s)
4.75–5.0V
Yes
Go to Step 7
No
Go to Step 5
4.75–5.0V
Go to Step 6
Go to Step 13
Go to Step9
Go to
Diagnostic Aids
Go to
Diagnostic Aids
Go to Step 8
Go to Step 9
Go to Step 10
8
3511–3653 Ohm at
1. Turn OFF the ignition.
20°C (68°F)
2. Disconnect the TCM from the J 47275 TCM
Breakout. Leave the OEM-side connected.
Refer to
Appendix
Q
3. Connect the transmission 20-way connector.
4. At J 47275-1 TCM Overlay, connect a DVOM.
Measure resistance between pin 54 and pin 58.
Is the resistance within the specified value?
1. Disconnect the 20-way connector at the
3511–3653 Ohm at
transmission and install J 47279 Transmission
20°C (68°F)
Breakout. Connect only the J 47279 Transmission
Refer to
Breakout to the transmission. The vehicle side of
Appendix Q
the harness should not be connected for this test.
2. At J 47279-1 Transmission Overlay, connect a
DVOM. Measure resistance between pin 18 and
pin 19 in transmission 20-way connector.
Is the resistance within the specified value?
6–88
Copyright © 2005 General Motors Corp.
7
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0711 Transmission Fluid Temperature Sensor Circuit Performance (cont’d)
Step
9
10
11
12
13
14
Action
NOTE: The vehicle OEM has responsibility for all
external wiring harnesses repair. Harness repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Value(s)
Coordinate with the vehicle OEM to repair or
replace the vehicle wiring.
Is the repair complete?
1. Remove the hydraulic control module assembly. 3511–3653 Ohm at
20°C (68°F)
2. Disconnect the sump thermistor from the internal
wiring harness.
Refer to
Appendix Q
3. Using a DVOM, measure thermistor resistance at
pins A and B.
Is the resistance within the specified value?
Replace the internal harness (refer to appropriate
mechanic’s tips).
Is the replacement complete?
Replace the sump thermistor (refer to appropriate
mechanic’s tips).
Is the replacement complete?
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
Refer to TCM diagnostic procedure, Section 3–6.
Is Section 3–6 complete?
In order to verify your repair:
1. Clear the DTC.
2. Using Allison DOC™ For PC–Service Tool,
monitor the transmission fluid temperature.
3. Drive the vehicle under normal operating
conditions. Watch for significant changes in TFT.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 14
No
Go to Step 11
Go to Step 12
Go to Step 14
Go to Step 14
Go to Step 14
Begin the
diagnosis again.
Go to Step 1
System OK
6–89
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0712 Transmission Fluid Temperature Sensor Circuit Low Input
END VIEW OF
20-WAY CONNECTOR
END VIEW OF
80-WAY CONNECTOR
1
6
7
10
11
14
15
20
61
80
41
60
21
40
1
20
TO RETARDER
CONTROL DEVICES
RETARDER
REQUEST SENSOR
(RESISTANCE
MODULE)
A
PWM
THROTTLE
SOURCE
B
C
TCM
THROTTLE
POSITION
SENSOR (TPS)
OR
ELECTRONIC
BRAKING (EBS)
RTDR PRESSURE
SENSOR
WIRE 156
WIRE 112
C
WIRE 144
B
WIRE 158
A
RETARDER TEMP
ENGINE TEMP
WIRE 175
WIRE 135
TRANSMISSION
ANALOG RETURN
OIL LEVEL
HALL
A
C
EFFECT
B
SUMP TEMP
19
16
15
18
PS1
NC*
* NORMALLY
3
56
RETARDER REQUEST SIGNAL
12
5V SENSOR VOLTAGE
44
THROTTLE POSITION OR
RTDR PRESSURE SIGNAL
58
ANALOG RETURN
75
RETARDER TEMP
35
ENGINE WATER TEMP
16
OIL LEVEL SENSOR
54
SUMP TEMP
77
PS1 DIAGNOSTIC
PRESSURE SWITCH
WIRE 158
WIRE 112
WIRE 116
WIRE 154
WIRE 177
CLOSED
V09069.01.00
6–90
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0712 Transmission Fluid Temperature Sensor Circuit Low Input
Circuit Description
The Transmission Fluid Temperature (TFT) sensor is incorporated into the internal wiring harness. The TFT sensor
is a thermistor that changes its resistance value based on the temperature of the transmission fluid. The
Transmission Control Module (TCM) supplies a 5V reference voltage signal to the TFT sensor and measures the
voltage drop in the circuit. When the transmission is cold, the sensor resistance is high and the TCM detects high
signal voltage. As the transmission fluid temperature warms to normal operating temperature, the resistance and the
signal voltage decrease. The TCM uses this information to control shift quality.
Conditions for Running the DTC
• The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater
than 9V and less than 32V (24V TCM).
•
The components are powered and engine speed is greater than 200 rpm and less than 7500 rpm for 5 seconds.
•
When engine coolant temperature sensor is present, engine is running. If engine runtime is less than 10
minutes, then engine coolant temperature must be above 20°C (68°F) for more than 20 seconds.
Conditions for Setting the DTC
The TCM detects transmission fluid temperature greater than a calibrated value for more than 2.5 seconds.
NOTE:
The TCM is detecting voltage. An extremely low input voltage implies low thermistor resistance, which
corresponds to an unrealistically high transmission fluid temperature measurement.
Actions Taken When the DTC Sets
When DTC P0712 is active, the following conditions will occur:
•
•
•
The CHECK TRANS light is illuminated.
DTC is stored in TCM history.
TCM uses calibration default for temperature values.
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
• Review Appendix A for diagnosing intermittent electrical fault conditions.
•
Inspect the wiring for poor electrical connections at the TCM and service brake switch. Look for the following
conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
•
When diagnosing for an intermittent short or open, massage the wiring harness while watching the test
equipment for a change.
Copyright © 2005 General Motors Corp.
6–91
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
•
You may have to drive the vehicle in order to experience a fault.
•
DTC P0712 may be caused by a short-to-ground on wire 154.
Test Description
This DTC requires the use of the J 47275 TCM Breakout and J 47279 Transmission Breakout. The numbers below
refer to step numbers on the diagnostic table.
2. This step tests for proper transmission fluid level and condition.
3. This step verifies which condition has set the DTC P0712.
4. This step tests for the proper 5V reference voltage at TCM with OEM harness connected.
5. This step tests for wire-to-wire shorts, shorts-to-ground, or an open on wire 154.
6. This step tests for 5V reference voltage without OEM harness.
7. This step tests for proper system circuit resistance value.
8. This step tests the resistance value of the internal harness and TFT sensor.
10. This step tests the resistance value of the internal TFT sensor.
DTC P0712 Transmission Fluid Temperature Sensor Circuit Low Input
Step
1
2
3
4
6–92
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Perform the Fluid Check Procedure (refer to
appropriate mechanic’s tips).
Is the transmission fluid level correct?
1. Install the Allison DOC™ For PC–Service Tool.
2. With the engine OFF, turn ON the ignition.
3. Record the failure record.
4. Clear the DTCs.
5. Monitor the TFT on Allison DOC™ For PC–
Service Tool.
6. Drive the vehicle and observe Allison DOC™ For
PC–Service Tool for an unrealistically high
temperature condition.
Is the Allison DOC™ For PC–Service Tool
transmission fluid temperature greater than 128°C
(262°F)?
1. Turn OFF the ignition.
2. Install J 47275 TCM Breakout at the TCM.
3. Disconnect the transmission 20-way connector.
4. Turn ON the ignition.
5. At J 47275-1 TCM Overlay, connect a DVOM.
Measure voltage between pins 54 and 58.
Is the voltage within the specified value?
Value(s)
Yes
Go to Step 2
Go to Step 3
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Go to Fluid Check
Procedure (refer to
mechanic’s tips)
>128°°C (262°°F)
Go to Step 4
Go to
Diagnostic Aids
4.75 to 5.0V
Go to Step 6
Go to Step 5
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0712 Transmission Fluid Temperature Sensor Circuit Low Input (cont’d)
Step
5
6
7
8
9
10
Action
Value(s)
1. Turn OFF the engine.
4.75–5.0V
2. Disconnect the 16-pin bypass connector on the
J 47275 TCM Breakout.
3. Turn ON the ignition.
4. Using a DVOM at J 47275-1 TCM Overlay,
measure voltage between pin 54 and 58.
Is the voltage within the specified value?
1. Turn OFF the ignition.
2. Disconnect the TCM from the J 47275 TCM
Breakout. Leave the OEM-side connected.
3. Disconnect the transmission 20-way connector, if
it was not disconnected in Step 4.
4. Reconnect the 16-pin bypass connector on
J 47275 TCM Breakout.
5. Using a DVOM at J 47275-1 TCM Overlay, test
for pin-to-pin shorts, or shorts-to-ground on wire
154.
Were any wiring defects found?
1. Turn OFF the ignition.
3511–3653 Ohm at
20°C (68°F)
2. Disconnect the TCM from the J 47275 TCM
Breakout. Leave the OEM-side connected.
Refer to
Appendix Q
3. Connect the transmission 20-way connector.
4. At J 47275-1 TCM Overlay, connect a DVOM.
Measure resistance between pin 54 to pin 58.
Is the resistance within the specified value?
1. Disconnect the 20-way connector at the
3511–3653 Ohm at
transmission and install J 47279 Transmission
20°C (68°F)
Breakout. Connect only the J 47279 Transmission
Refer to
Breakout to the transmission. The vehicle side of
Appendix
Q
the harness should not be connected for this test.
2. At J 47279-1 Transmission Overlay, connect a
DVOM. Measure resistance between pin 18 and
pin 19 in transmission 20-way connector.
Is the resistance within the specified value?
NOTE: The vehicle OEM has responsibility for all
external wiring harnesses repair. Harness repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Coordinate with the vehicle OEM to repair or
replace the vehicle wiring.
Is the repair complete?
1. Remove the hydraulic control module assembly. 3511–3653 Ohm at
20°C (68°F)
2. Disconnect the sump thermistor from the internal
wiring harness.
Refer to
Appendix Q
3. Using a DVOM, measure thermistor resistance at
pins A and B.
Is the resistance within the specified value?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 6
No
Go to Step 13
Go to
Diagnostic Aids
Go to Step 7
Go to
Diagnostic Aids
Go to Step 8
Go to Step 9
Go to Step 10
Go to Step 14
Go to Step 11
Go to Step 12
6–93
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0712 Transmission Fluid Temperature Sensor Circuit Low Input (cont’d)
Step
11
12
13
14
6–94
Action
Replace the internal harness (refer to appropriate
mechanic’s tips).
Is the replacement complete?
Replace the sump thermistor (refer to appropriate
mechanic’s tips).
Is the replacement complete?
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
Value(s)
Refer to TCM diagnostic procedure, Section 3–6.
Is Section 3–6 complete?
In order to verify your repair:
1. Clear the DTC.
2. Using Allison DOC™ For PC–Service Tool,
monitor the transmission fluid temperature.
3. Drive the vehicle under normal operating
conditions. Watch for significant changes in TFT.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 14
No
Go to Step 14
Go to Step 14
Begin the
diagnosis again.
Go to Step 1
System OK
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0713 Transmission Fluid Temperature Sensor Circuit High Input
END VIEW OF
20-WAY CONNECTOR
END VIEW OF
80-WAY CONNECTOR
1
6
7
10
11
14
15
20
61
80
41
60
21
40
1
20
TO RETARDER
CONTROL DEVICES
RETARDER
REQUEST SENSOR
(RESISTANCE
MODULE)
A
PWM
THROTTLE
SOURCE
B
C
TCM
THROTTLE
POSITION
SENSOR (TPS)
OR
ELECTRONIC
BRAKING (EBS)
RTDR PRESSURE
SENSOR
WIRE 156
WIRE 112
C
WIRE 144
B
WIRE 158
A
RETARDER TEMP
ENGINE TEMP
TRANSMISSION
ANALOG RETURN
OIL LEVEL
HALL
A
C
EFFECT
B
SUMP TEMP
19
16
15
18
PS1
NC*
* NORMALLY
3
WIRE 175
WIRE 135
56
RETARDER REQUEST SIGNAL
12
5V SENSOR VOLTAGE
44
THROTTLE POSITION OR
RTDR PRESSURE SIGNAL
58
ANALOG RETURN
75
RETARDER TEMP
35
ENGINE WATER TEMP
16
OIL LEVEL SENSOR
54
SUMP TEMP
77
PS1 DIAGNOSTIC
PRESSURE SWITCH
WIRE 158
WIRE 112
WIRE 116
WIRE 154
WIRE 177
CLOSED
V09069.01.00
Copyright © 2005 General Motors Corp.
6–95
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0713 Transmission Fluid Temperature Sensor Circuit High Input
Circuit Description
The Transmission Fluid Temperature (TFT) sensor is incorporated into the internal wiring harness. The TFT sensor
is a thermistor that changes its resistance value based on the temperature of the transmission fluid. The
Transmission Control Module (TCM) supplies a 5V reference voltage signal to the TFT sensor and measures the
voltage drop in the circuit. When the transmission is cold, the sensor resistance is high and the TCM detects high
signal voltage. As the transmission fluid temperature warms to normal operating temperature, the resistance and the
signal voltage decrease. The TCM uses this information to control shift quality.
Conditions for Running the DTC
• The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater
than 9V and less than 32V (24V TCM).
•
The components are powered and engine speed is greater than 200 rpm and less than 7500 rpm for 5 seconds.
•
When engine coolant temperature sensor is present, engine is running. If engine runtime is less than
10 minutes, then engine coolant temperature must be above 20ºC (68ºF) for more than 20 seconds.
Conditions for Setting the DTC
The TCM detects transmission fluid temperature less than or equal to a calibrated value for more than 2.5 seconds.
NOTE:
The TCM is detecting voltage. A high input voltage implies high thermistor resistance, which
corresponds to an extremely cold transmission fluid temperature measurement.
Actions Taken When the DTC Sets
When DTC P0713 is active, the following conditions will occur:
•
•
•
The CHECK TRANS light is illuminated.
DTC is stored in TCM history.
TCM uses calibration default for temperature values.
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
• DTC P0713 may be caused by a short-to-battery on wire 154. If DTC P0713 is accompanied by a DTC P2185
and/or P2743, the problem is most likely a short-to-battery on wire 154, wire 135, or wire 175.
• DTC code P0713 may also be caused by an open in wire 154 or 158.
• Review Appendix A for diagnosing intermittent electrical fault conditions.
• Inspect the wiring for poor electrical connections at the TCM and service brake switch. Look for the following
conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
6–96
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
•
When diagnosing for an intermittent short or open, massage the wiring harness while watching the test
equipment for a change.
•
You may have to drive the vehicle in order to experience a fault.
Test Description
This DTC requires the use of the J 47275 TCM Breakout and J 47279 Transmission Breakout. The numbers below
refer to step numbers on the diagnostic table.
2. This step tests for proper transmission fluid level and condition.
3. This step verifies which condition has set the DTC P0712.
4. This step tests for the proper 5V reference voltage at TCM with OEM harness connected.
5. This step tests for proper 5V reference voltage at TCM without the OEM harness.
6. This step tests for wiring defects in external harness.
7. This step tests for proper system circuit resistance value.
8. This step tests the resistance value of the internal harness and TFT sensor.
10. This step tests the resistance value of the internal TFT sensor.
DTC P0713 Transmission Fluid Temperature Sensor Circuit High Input
Step
1
2
3
4
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Perform the Fluid Check Procedure (refer to
appropriate mechanic’s tips).
Is the transmission fluid level correct?
1. Install the Allison DOC™ For PC–Service Tool.
With the engine OFF, turn ON the ignition.
2. Record the failure record.
3. Clear the DTCs.
4. Monitor the TFT on Allison DOC™ For PC–
Service Tool.
5. Drive the vehicle and observe Allison DOC™ For
PC–Service Tool for an unrealistically low
temperature condition.
Is the Allison DOC™ For PC–Service Tool
transmission fluid temperature less than –45°C
(–49°F)?
1. Turn OFF the ignition.
2. Install J 47275 TCM Breakout at the TCM.
3. Disconnect the transmission 20-way connector.
4. Turn ON the ignition.
5. Using a DVOM at J 47275-1 TCM Overlay,
measure voltage between pins 54 and 58.
Is the voltage within the specified value?
Value(s)
Yes
Go to Step 2
Go to Step 3
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Go to Fluid Check
Procedure (refer to
mechanic’s tips)
–45°°C (–49°°F)
Go to Step 4
Go to
Diagnostic Aids
4.75 to 5.0V
Go to Step 7
Go to Step 5
Copyright © 2005 General Motors Corp.
6–97
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0713 Transmission Fluid Temperature Sensor Circuit High Input (cont’d)
Step
5
6
7
8
9
Action
Value(s)
1. Turn OFF the ignition.
4.75–5.0V
2. Disconnect the 16-pin bypass connector on
J 47275 TCM Breakout.
3. Turn ON the ignition.
4. Using a DVOM at J 47275-1 TCM Overlay,
measure voltage between pin 54 and 58.
Is the voltage within the specified value?
1. Turn OFF the ignition.
2. Disconnect the TCM from the J 47275 TCM
Breakout. Leave the OEM-side connected.
3. Reconnect the 16-pin bypass connector on
J 47275 TCM Breakout.
4. Disconnect the transmission 20-way connector.
5. Disconnect the engine coolant temperature sensor
and retarder temperature sensor.
6. Using a DVOM at J 47275-1 TCM Overlay, test
for opens in wires 154 and 158.
7. Also test for wire-to-wire shorts or shorts-tobattery on wire 135, wire 154, or wire 175.
Were any wiring defects found?
1. Turn OFF the ignition.
3511–3653 Ohm at
20°C (68°F)
2. Verify the OEM-side harness is connected to the
J 47275 TCM Breakout. Leave the TCM
Refer to
disconnected.
Appendix Q
3. Reconnect the transmission 20-way connector.
4. Using a DVOM at J 47275-1 TCM Overlay,
measure the resistance between pin 54 and 58.
Is the resistance within the specified value?
1. Disconnect the 20-way connector at the
3511–3653 Ohm at
transmission and install J 47279 Transmission
20°C (68°F)
Breakout. Connect the J 47279 Transmission
Refer to
Breakout to the transmission only. The vehicle
Appendix Q
side of the harness should not be connected for
this test.
2. Using a DVOM at J 47279-1 Transmission
Overlay, measure resistance between pins 18 and
19 in the 20-way connector.
Is the resistance within the specified value?
NOTE: The vehicle OEM has responsibility for all
external wiring harnesses repair. Harness repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Coordinate with the vehicle OEM to repair or
replace the vehicle wiring.
Is the repair complete?
6–98
Copyright © 2005 General Motors Corp.
Yes
Go to Step 6
No
Go to Step 13
Go to Step 9
Go to
Diagnostic Aids
Go to
Diagnostic Aids
Go to Step 8
Go to Step 9
Go to Step 10
Go to Step 14
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0713 Transmission Fluid Temperature Sensor Circuit High Input (cont’d)
Step
10
11
12
13
14
Action
Value(s)
1. Remove the hydraulic control module assembly. 3511–3653 Ohm at
20°C (68°F)
2. Disconnect the sump thermistor from the internal
wiring harness.
Refer to
Appendix Q
3. Using a DVOM, measure thermistor resistance at
pins A and B.
Is the resistance within the specified value?
Replace the internal harness (refer to appropriate
mechanic’s tips).
Is the replacement complete?
Replace the sump thermistor (refer to appropriate
mechanic’s tips).
Is the replacement complete?
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
Refer to TCM diagnostic procedure, Section 3–6.
Is Section 3–6 complete?
In order to verify your repair:
1. Clear the DTC.
2. Using Allison DOC™ For PC–Service Tool,
monitor the transmission fluid temperature.
3. Drive the vehicle under normal operating
conditions. Watch for significant changes in TFT.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 11
No
Go to Step 12
Go to Step 14
Go to Step 14
Go to Step 14
Begin the
diagnosis again.
Go to Step 1
System OK
6–99
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0716 Turbine Speed Sensor Circuit Performance
END VIEW OF
20-WAY CONNECTOR
END VIEW OF
80-WAY CONNECTOR
1
6
7
10
11
14
15
20
20
1
40
21
60
41
80
61
3000 SERIES
TURBINE
SPEED
SENSOR
A
B
4000 SERIES
A
TURBINE
SPEED
SENSOR
B
A
B
WIRE 180
WIRE 120
80
TURBINE SPEED HI
20
TURBINE SPEED LO
Current Resistance (Ohms) Former Resistance (Ohms)
Before January, 2006
January, 2006
200
250
TCM
TEMP (˚F)
TEMP (˚C)
–40
–40
SPEED SENSOR CIRCUITS
340
300
68
20
Use twisted pairs of wires
450
400
230
110
V09137.00.01
6–100
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0716 Turbine Speed Sensor Circuit Performance
Circuit Description
Speed sensors are variable reluctance devices that convert mechanical motion to an AC voltage. Each sensor
consists of a wire coil wrapped around a pole piece that is adjacent to a permanent magnet. These elements are
contained in a housing that is mounted adjacent to a rotating ferrous member. Two signal wires extend from one
end of the housing and an exposed end of the pole piece is at the opposite end of the housing. The permanent
magnet produces lines of flux around the pole piece. As a ferrous object (a rib on the rotating clutch drum)
approaches and passes through the gap at the end of the pole piece, an AC voltage pulse is induced in the wire coil.
The Transmission Control Module (TCM) calculates the frequency of these AC pulses and converts it to a speed
value. The AC voltage generated varies from 150mV at low speed to 15V at high speed. The signal wires from the
sensor are formed as twisted pairs to cancel magnetically induced fields. The cable is also shielded to protect from
voltage-related fields. Using two-wire differential input at the TCM eliminates noise from other sources.
Conditions for Running the DTC
• The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater
than 9V and less than 32V (24V TCM).
•
Turbine speed is above 200 rpm.
•
Shift is complete and range attained is not neutral.
•
For fire truck vocation, pump not pumping.
Conditions for Setting the DTC
DTC P0716 is set when one of the following three conditions occur:
• Unrealistic large changes in turbine speed. Failure is set if an unrealistic change in transmission turbine speed
is detected at or above 800 rpm for 0.15 seconds.
• Noisy turbine speed. Noise is determined with two counters. A low counter is incremented when turbine speed
change is below 800 rpm for 2.0 seconds. A high counter is incremented when turbine speed change is above
800 rpm. When both counters accumulate 5 events, a failure is set.
• Wires to speed sensors swapped. Failure is set if commanded range is not Neutral and oncoming clutch control
is complete, and engine and turbine speed are greater than 100 rpm.
Actions Taken When the DTC Sets
When DTC P0716 is active, the following conditions will occur:
•
If failure occurs while in a forward range and a shift has been completed, the transmission will remain in the
current range.
•
If failure occurs while in a forward range and a shift is in progress, the transmission will return to the previous
range, except in post-shift state, then the transmission will continue to the commanded range.
•
DTC P0716 is stored in TCM history.
•
The CHECK TRANS light illuminates.
•
The TCM inhibits TCC engagement.
•
The TCM freezes shift adapts.
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Copyright © 2005 General Motors Corp.
6–101
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
Diagnostic Aids
•
Inspect the wiring for poor electrical connections at the TCM and service brake switch. Look for the following
conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
•
You may have to drive the vehicle in order to experience a fault.
•
If the condition is intermittent, connect the Allison DOC™ For PC–Service Tool and observe the speed sensor
indicated by the code. If the signal is erratic, investigate and eliminate the following:
— Intermittent wiring connection
— Excessive vibration (driveline or engine torsionals)
— Irregular sensor gap (loose sensor, loose tone wheel, or damaged tone wheel).
•
Install a known good speed sensor and see if normal function is restored to rule out an internal short or open in
the sensor removed.
•
Check that the speed sensor wiring consists of twisted pairs at the rate of 12 to 16 twists per 300 mm. These
twists must extend the entire length of the wiring harness to within at least 50 mm of the speed sensor
connector.
•
Install a known good TCM, if available. If the DTC does not return, reinstall the old TCM to verify the repair.
Test Description
The numbers below refer to step numbers on the diagnostic table.
2. This step tests for proper ignition voltage.
3. This step tests for proper turbine speed sensor resistance at the TCM side of the harness.
4. This step tests for turbine speed sensor resistance.
DTC P0716 Turbine Speed Sensor Circuit Performance
Step
1
2
6–102
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Install the Allison DOC™ For PC–Service Tool.
1. Start the engine.
2. Record the failure records.
3. Clear the DTCs.
4. Using Allison DOC™ For PC–Service Tool,
measure ignition voltage.
Is voltage within specified values?
Value(s)
Yes
Go to Step 2
9–18V (12V TCM)
18–32V (24V TCM)
Go to Step 3
Copyright © 2005 General Motors Corp.
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Resolve voltage
problems (refer to
DTC P0882 and
P0883)
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0716 Turbine Speed Sensor Circuit Performance (cont’d)
Step
3
4
5
6
7
Action
1. Turn OFF the ignition.
2. Disconnect the 80-way connector at the TCM.
3. Using a DVOM, measure resistance between
terminal pin 20 and terminal 80 at the OEM-side
of the 80-way connector.
Is the speed sensor resistance within the specified
value?
1. Disconnect the wiring harness from the turbine
speed sensor.
2. Using a DVOM, check the resistance between the
speed sensor terminals.
Is the speed sensor resistance within the specified
value?
NOTE: The vehicle OEM has responsibility for all
external wiring harness repairs. Harness repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Value(s)
Refer to Speed
Sensor Resistance
Table 6–10
Yes
Go to
Diagnostic Aids
No
Go to Step 4
Refer to Speed
Sensor Resistance
Table 6–10
Go to Step 5
Go to Step 6
Go to Step 7
Coordinate with the vehicle OEM to repair or
replace the vehicle wiring.
Is the repair complete?
Replace the turbine speed sensor (refer to
appropriate service manual).
Is replacement complete?
In order to verify your repair:
1. Clear the DTC.
2. Drive the vehicle under normal operating
conditions.
3. Using Allison DOC™ For PC–Service Tool,
monitor turbine speed sensor operation.
Did the DTC return?
Go to Step 7
Begin the
diagnosis again.
Go to Step 1
System OK
Table 6–10. Speed Sensor Temperature Resistance
Current Resistance (Ohms) Former Resistance (Ohms)
January, 2006
Before January, 2006
Temp ˚F
Temp ˚C
250
200
–40
–40
340
300
68
20
450
400
230
110
Copyright © 2005 General Motors Corp.
6–103
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0717 Turbine Speed Sensor Circuit No Signal
END VIEW OF
20-WAY CONNECTOR
END VIEW OF
80-WAY CONNECTOR
1
6
7
10
11
14
15
20
20
1
40
21
60
41
80
61
3000 SERIES
TURBINE
SPEED
SENSOR
A
B
4000 SERIES
A
TURBINE
SPEED
SENSOR
B
A
B
WIRE 180
WIRE 120
80
TURBINE SPEED HI
20
TURBINE SPEED LO
Current Resistance (Ohms) Former Resistance (Ohms)
Before January, 2006
January, 2006
200
250
TCM
TEMP (˚F)
TEMP (˚C)
–40
–40
SPEED SENSOR CIRCUITS
340
300
68
20
Use twisted pairs of wires
450
400
230
110
V09137.00.01
6–104
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0717 Turbine Speed Sensor Circuit No Signal
Circuit Description
Speed sensors are variable reluctance devices that convert mechanical motion to an AC voltage. Each sensor
consists of a wire coil wrapped around a pole piece that is adjacent to a permanent magnet. These elements are
contained in a housing that is mounted adjacent to a rotating ferrous member. Two signal wires extend from one
end of the housing and an exposed end of the pole piece is at the opposite end of the housing. The permanent
magnet produces lines of flux around the pole piece. As a ferrous object (a rib on the rotating clutch drum)
approaches and passes through the gap at the end of the pole piece, an AC voltage pulse is induced in the wire coil.
The Transmission Control Module (TCM) calculates the frequency of these AC pulses and converts it to a speed
value. The AC voltage generated varies from 150mV at low speed to 15V at high speed. The signal wires from the
sensor are formed as twisted pairs to cancel magnetically induced fields. The cable is also shielded to protect from
voltage-related fields. Using two-wire differential input at the TCM eliminates noise from other sources.
Conditions for Running the DTC
• The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater
than 9V and less than 32V (24V TCM).
•
For fire truck vocation, pump not pumping.
•
Shifting complete.
•
Reverse-to-Neutral shift not in progress.
•
Engine running.
•
Range attained is not Neutral.
•
No hydraulic default condition due to loss of ignition voltage.
•
Transmission fluid temperature above –1.1°C (30°F).
•
For low turbine speed test:
— Transmission output speed greater than or equal to 150 rpm, or
— Transmission output speed greater than or equal to 150 rpm and engine speed greater than or equal to
400 rpm.
Conditions for Setting the DTC
DTC P0717 is set when one of the following conditions occur:
•
Unrealistic large change in turbine speed. A failure pending is set if the TCM detects a change in turbine speed
of more than 800 rpm. The transmission locks in current range in response to a failure pending condition.
•
Unrealistic low value in turbine speed. A failure pending is set if turbine speed is detected below 61 rpm. A
failure is set when turbine speed is below 61 rpm and output speed is detected above 500 rpm for more than
1 second.
Actions Taken When the DTC Sets
When DTC P0717 is active, the following conditions will occur:
•
If failure occurs while in a forward range and a shift has been completed, the transmission will remain in the
current range.
•
If failure occurs while in a forward range and a shift is in progress, the transmission will return to the previous
range, except in post-shift state, then the transmission will continue to the commanded range.
•
DTC P0717 is stored in TCM history.
Copyright © 2005 General Motors Corp.
6–105
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
•
The CHECK TRANS light illuminates.
•
The TCM freezes shift adapts (DNA).
•
The TCM inhibits TCC engagement.
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
•
Inspect the wiring for poor electrical connections at the TCM and service brake switch. Look for the following
conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
•
You may have to drive the vehicle in order to experience a fault.
•
If the condition is intermittent, connect the Allison DOC™ For PC–Service Tool and observe the speed sensor
indicated by the code. If the signal is erratic, investigate and eliminate the following:
— Intermittent wiring connection
— Excessive vibration (driveline or engine torsionals)
— Irregular sensor gap (loose sensor, loose tone wheel, or damaged tone wheel).
•
Install a known good speed sensor and see if normal function is restored to rule out an internal short or open in
the sensor removed.
•
Check that the speed sensor wiring consists of twisted pairs at the rate of 12 to 16 twists per 300 mm. These
twists must extend the entire length of the wiring harness to within at least 50 mm of the speed sensor
connector.
Test Description
The numbers below refer to step numbers on the diagnostic table.
2. This step tests ignition voltage.
3. This step tests for proper turbine speed sensor resistance at the TCM side of the harness.
4. This step tests for turbine speed sensor resistance.
DTC P0717 Turbine Speed Sensor Circuit No Signal
Step
1
6–106
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
Copyright © 2005 General Motors Corp.
Yes
Go to Step 2
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0717 Turbine Speed Sensor Circuit No Signal (cont’d)
Step
2
3
4
5
6
7
Action
Value(s)
Install the Allison DOC™ For PC–Service Tool. 9–18V (12V TCM)
18–32V (24V TCM)
Start the engine.
Record the failure records.
Clear the DTCs.
Using Allison DOC™ For PC–Service Tool,
measure ignition voltage.
Is voltage within specified values?
1. Turn OFF the ignition.
Refer to Speed
Sensor
Resistance
2. Disconnect the 80-way connector at the TCM.
Table
6–11
3. Using a DVOM, measure resistance between
terminal 20 and terminal 80 in the OEM-side of
the 80-way connector.
Is the speed sensor resistance within the specified
value?
1. Disconnect the wiring harness from the turbine
Refer to Speed
speed sensor.
Sensor Resistance
2. Using a DVOM, check the resistance between the
Table 6–11
speed sensor terminals.
Is the speed sensor resistance within the specified
value?
NOTE: The vehicle OEM has responsibility for all
external wiring harness repairs. Harness repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Yes
Go to Step 3
No
Resolve voltage
problems (refer to
DTC P0882 and
P0883)
Go to
Diagnostic Aids
Go to Step 4
Go to Step 5
Go to Step 6
1.
2.
3.
4.
5.
Coordinate with the vehicle OEM to repair or
replace the vehicle wiring.
Is the repair complete?
Replace the turbine speed sensor (refer to
appropriate service manual).
Is replacement complete?
In order to verify your repair:
1. Clear the DTC.
2. Drive the vehicle under normal operating
conditions.
3. Using Allison DOC™ For PC–Service Tool,
monitor turbine speed sensor operation.
Did the DTC return?
Go to Step 7
Go to Step 7
Begin the
diagnosis again.
Go to Step 1
System OK
Table 6–11. Speed Sensor Temperature Resistance
Current Resistance (Ohms) Former Resistance (Ohms)
January, 2006
Before January, 2006
Temp ˚F
Temp ˚C
250
200
–40
–40
340
300
68
20
450
400
230
110
Copyright © 2005 General Motors Corp.
6–107
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0719 Brake Switch ABS Input Low
END VIEW OF
80-WAY CONNECTOR
61
80
41
60
21
40
1
20
ABS INPUT (–)
ABS INPUT (–)
Use this configuration if the ABS system
provides a ground (–) signal when active.
Use this configuration if the ABS system
provides a ground (–) signal when active.
ANTI-LOCK
BRAKE
CONTROLS
TCM
21
WIRE 121
ABS
RESPONSE
BRAKE
PRESSURE
SWITCH
N.C.
WIRE 121
ABS RESPONSE
OPTIONAL
CUSTOMER- FURNISHED
VEHICLE INTERFACE
WIRING CONNECTOR
ALL ITEMS SHOWN,
EXCEPT TCM,
ARE CUSTOMER-FURNISHED
SWITCHED
POWER
ABS INPUT (+)
COM N.O.
RELAY
SHOWN
DE-ENERGIZED
ABS ACTIVATION VIA
J1939 LINK
Use this configuration if the ABS system
provides a power (+) signal when active.
WIRE 103
SIGNAL RETURN
ANTI-LOCK
BRAKE
CONTROLS
WIRE 103
SIGNAL RETURN
ANTI-LOCK
BRAKE
CONTROLS
SAE J1939
VEHICLE COMMUNICATION
INTERFACE
See appropriate
“Installation Schematic”
installation drawing for
wire and pin numbers.
BRAKE
PRESSURE
SWITCH
N.C.
WIRE 121
ABS RESPONSE
COM N.O.
TCM
OPTIONAL
CUSTOMER- FURNISHED
VEHICLE INTERFACE
WIRING CONNECTOR
RELAY
SHOWN
DE-ENERGIZED
ALL ITEMS SHOWN,
EXCEPT TCM,
ARE CUSTOMER-FURNISHED
V09143.00.00
6–108
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0719 Brake Switch ABS Input Low
Circuit Description
The Transmission Control Module (TCM) can be calibrated to receive an anti-lock brake input from either an
analog input wire or the digital data link. A switched relay activated by the anti-lock brake system (ABS) controller
may provide a direct input to the TCM, or the TCM can receive ABS status as a digital message over the vehicle’s
communications data link.
Conditions for Running the DTC
•
The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater
than 9V and less than 32V (24V TCM).
•
The components are powered and engine speed is greater than 200 rpm and less than 7500 rpm for 5 seconds.
Conditions for Setting the DTC
DTC P0719 sets if the TCM is calibrated to receive the ABS status signal and the TCM senses one acceleration
event with the ABS status ON.
Actions Taken When the DTC Sets
When DTC P0719 is active, the following conditions will occur:
•
The TCM does not illuminate the CHECK TRANS light.
•
DTC is stored in TCM history.
•
TCM may disengage the torque converter clutch (TCC).
•
The TCM uses the default assumption that ABS is OFF.
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
•
When an analog input wire is used, the ABS signal is received on wire 121. The ABS controller may directly
pull wire 121 to ground or use a relay to complete a circuit between wire 121 and wire 103. If a data link is
used, the TCM receives ABS status as part of J1939 message parameter PGN 61441, Electronic Brake
Controller 1 (EBC1).
•
DTC P0719 indicates the TCM has detected ABS status ON for a single acceleration event. The code can be
caused by:
— Faulty wiring
— Faulty connections to the ABS relay
— A faulty ABS relay
— Another controller improperly broadcasting ABS status on the data link when ABS is not installed or
operating
— A fault in the ABS system itself
— A faulty TCM.
Copyright © 2005 General Motors Corp.
6–109
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
•
Inspect the wiring for poor electrical connections at the TCM and service brake switch. Look for the following
conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
•
J1939 ABS status can be read on Allison DOC™ For PC–Service Tool. Monitor data link communications
using Data Bus Viewer.
Test Description
The numbers below refer to step numbers on the diagnostic table.
2. This step tests for an active DTC.
3. This step determines if ABS status is being communicated by a data link message.
DTC P0719 Brake Switch ABS Input Low
Step
1
2
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
1.
2.
3.
4.
Value(s)
Install the Allison DOC™ For PC–Service Tool.
Start the engine.
Record the failure records.
Clear the DTCs and drive the vehicle. Attempt to
duplicate same operating conditions observed in
failure records.
Yes
Go to Step 2
Go to Step 3
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Go to
Diagnostic Aids
NOTE: This DTC indicates that the ABS signal is
present for more than a single acceleration event.
3
4
Did DTC P0719 return?
Using Allison DOC™ For PC–Service Tool Data
Bus Viewer, observe status of ABS. Consult Allison
DOC™ For PC–Service Tool User’s Guide
(GN3433EN) for instructions on using Data Bus
Viewer.
Is J1939 ABS status ON during acceleration events?
NOTE: Allison Transmission is not responsible for
data link messages that originate in other
controllers. Repairs not associated with the
transmission controller are not covered by Allison
Transmission warranty.
Coordinate with the vehicle or engine OEM to
correct the cause of the inconsistent J1939 ABS
status message.
Is the repair complete?
6–110
Copyright © 2005 General Motors Corp.
Go to Step 4
Go to Step 8
Go to Step 5
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0719 Brake Switch ABS Input Low (cont’d)
Step
5
6
7
8
Action
1. Remove the ABS input wire (121) from the
80-way connector.
2. Clear code and test drive vehicle.
Did the code return?
Return vehicle to OEM for troubleshooting of
wiring leading to ABS controller.
Was the problem found and corrected?
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
Value(s)
Refer to TCM diagnostic procedure, Section 3–6.
Is Section 3–6 complete?
In order to verify your repair:
1. Clear the DTC.
2. Use to Allison DOC™ For PC–Service Tool
monitor ABS status.
3. Drive the vehicle under conditions noted in
failure records.
4. Confirm with the service tool in the test passed
section that the diagnostic test was run.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 7
No
Go to Step 6
Go to Step 8
Go to Step 8
Begin the
diagnosis again.
Go to Step 1
System OK
6–111
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P071A RELS Input Failed On
END VIEW OF
80-WAY CONNECTOR
61
80
41
60
21
40
1
20
SERVICE BRAKE
PRESSURE
SWITCH
SWITCH CLOSES
WHEN DOOR
IS OPENED
SWITCH CLOSES
WHEN BRAKES
ARE APPLIED
WIRE 123 RELS
23
TCM
DOOR SWITCH
(OPTIONAL)
OPTIONAL
CUSTOMER-FURNISHED
VEHICLE INTERFACE
WIRING CONNECTOR
RELS
ENABLE
(OPTIONAL)
SWITCHED
POWER
V09145.00.00
Circuit Description
The Transmission Control Module (TCM) can be calibrated to receive an input from the service brakes to activate
and deactivate the Reduced Engine Load at Stop (RELS) feature. The input signal consists of switched power
provided through a normally open service brake pressure switch. The switch closes when brakes are applied to
supply switched power to the RELS input pin at the TCM. Supplemental controls such as a door switch or RELS
enable switch may be wired in series with the brake switch.
When RELS is active, the TCM automatically commands transmission operation at a reduced load state similar to
neutral. The vehicle must be at a stop with the service brakes applied and the throttle closed. RELS is de-activated
when the service brake pressure switch is opened and switched power is removed from the RELS input pin at the
TCM. The service brake input on SAE J1939 communications link CANNOT be used as an input for RELS.
Conditions for Running the DTC
•
The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater
than 9V and less than 32V (24V TCM).
•
Engine speed is greater than 200 rpm and less than 7500 rpm for 5 seconds.
6–112
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P071A RELS Input Failed On
Conditions for Setting the DTC
Both of the following conditions must be met for the DTC to be set:
•
DTC P071A sets if the TCM is calibrated to receive the RELS input signal.
•
RELS input is active during one acceleration event.
Actions Taken When the DTC Sets
When DTC P071A is active, the following conditions will occur:
•
The CHECK TRANS light is illuminated.
•
DTC is stored in TCM history.
•
TCM inhibits RELS operation.
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
•
The RELS function is active when a service brake pressure switch is closed to supply switched power on wire
123 to pin 23 at the TCM.
•
DTC P071A indicates the TCM has detected a RELS input signal during one acceleration event. The code can
be caused by:
— Faulty wiring
— Faulty connections to service brake switch
— A faulty service brake switch
— Faulty TCM.
•
Inspect the wiring for poor electrical connections at the TCM and service brake pressure switch. Look for the
following conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
Test Description
This DTC requires the use of the J 47275 TCM Breakout. The numbers below refer to step numbers on the
diagnostic table.
2. This step tests for an active DTC.
3. This step tests for status of analog input wire 123.
4. This step tests for the presence of ignition voltage on wire 123.
5. This step tests for proper service brake switch function.
Copyright © 2005 General Motors Corp.
6–113
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P071A RELS Input Failed On
Step
1
2
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
1.
2.
3.
4.
Value(s)
Install the Allison DOC™ For PC–Service Tool.
Start the engine.
Record the failure records.
Clear the DTCs and drive the vehicle. Attempt to
duplicate same operating conditions observed in
failure records.
Yes
Go to Step 2
Go to Step 3
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Go to
Diagnostic Aids
NOTE: This DTC indicates that the RELS input is
on during one acceleration event.
3
4
5
6
Did DTC P071A return?
1. Turn ON the ignition.
2. Using Allison DOC™ For PC–Service Tool,
observe status of RELS input wire 123.
Does wire 123 go ON when service brakes are
applied and go OFF when service brakes are
released?
1. Turn OFF the ignition.
2. Disconnect the TCM 80-way connector.
3. Connect TCM and OEM-side connectors to the
J 47275 TCM Breakout.
4. Turn ON the ignition.
5. Release service brakes.
NOTE: Ignition voltage should not be present at
TCM pin 23 when brakes are released.
6. At J 47275-1 TCM Overlay, connect a DVOM
and measure voltage between pins 23 and an
isolated ground.
Is ignition voltage present at pin 23 when service
brakes are released?
1. Turn OFF the ignition.
2. Using a DVOM, check for continuity across the
service brake switch when brakes are applied, and
no continuity when brakes are released.
Does the switch close when service brakes are
applied and open when brakes are released?
NOTE: The vehicle OEM has responsibility for all
external harness repairs. Harness repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Coordinate with the vehicle OEM to repair or
replace the vehicle wiring.
Is the repair complete?
6–114
Copyright © 2005 General Motors Corp.
Go to
Diagnostic Aids
Go to Step 4
Go to Step 5
Go to Step 8
Go to Step 6
Go to Step 7
Go to Step 9
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P071A RELS Input Failed On (cont’d)
Step
7
8
9
Action
NOTE: The vehicle OEM has responsibility for
vehicle input/output switch repairs. Switch repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Value(s)
Coordinate with the vehicle OEM to repair or
replace the service brake switch.
Is the repair complete?
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
Refer to TCM diagnostic procedure, Section 3–6.
Is Section 3–6 complete?
In order to verify your repair:
1. Clear the DTC.
2. Use Allison DOC™ For PC–Service Tool to
monitor RELS status.
3. Drive the vehicle under conditions noted in
failure records.
4. Confirm with the service tool in the test passed
section that the diagnostic test was run.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 9
No
Go to Step 9
Begin the
diagnosis again.
Go to Step 1
System OK
6–115
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P071D General Purpose Input Fault
END VIEW OF
80-WAY CONNECTOR
64
1
3
42
9
TCM
69
OPTIONAL
CUSTOMERFURNISHED
VEHICLE
INTERFACE
WIRING
CONNECTOR(S)
61
80
41
60
21
40
1
20
WIRE 164 SERVICE INDICATOR
WIRE 101 AUX FUNCTION RANGE INHIBIT INPUT 1
WIRE 103 SIGNAL RETURN
WIRE 142 AUX FUNCTION RANGE INHIBIT
WIRE 109
WIRE
169
OPTIONAL
VIM
*
*
ALL ITEMS SHOWN,
EXCEPT TCM, ARE
CUSTOMER-FURNISHED
+
_
AUXILIARY
FUNCTION
SENSE SWITCH 2
SWITCH IS CLOSED
WHEN AUXILIARY
EQUIPMENT IS
OPERATING
BATTERY
GROUND
* SEE VIM INSTALLATION DRAWING
FOR INTERFACE REQUIREMENTS
SWITCHED POWER
SERVICE
TRANS
INPUT 2
AUXILIARY
FUNCTION
SELECT
SWITCH 1
IF CURRENT IN LAMP CIRCUIT
EXCEEDS 0.5 AMP,
GROUND LAMP THROUGH A RELAY
SWITCHED
POWER
SWITCH IS
CLOSED WHEN
AUXILIARY
EQUIPMENT
IS OPERATING
SERVICE
TRANS
N.C.
COM N.O.
WIRE 164
RELAY SHOWN DE-ENERGIZED
NOTE: Both input signals must turn on within 120 seconds. If the state of
the two input signals is different for longer than this time period, the “SERVICE
TRANS” light will be illuminated. A code will be stored in memory, and
Neutral-to-Range shifts will NOT be inhibited.
NOTE: The “SERVICE TRANS” light must be mounted in the dash and in
clear view of the operator. Preferred lens color is red (amber is acceptable).
V09141.00.00
Circuit Description
Some emergency vehicles are equipped with an input function known as Auxiliary Function Range Inhibit
(Special), which prevents inadvertent range selection when auxiliary equipment is operating. This function is
enabled under the following conditions:
•
Input wire 101 is connected to signal return wire 103, and
•
Input wire 142 is connected to battery ground.
In a typical installation, a dash-mounted auxiliary equipment selector switch completes the circuit between wires
101 and 103. A second switch closes during operation of the auxiliary equipment to complete the circuit between
wire 142 and battery ground. Both switches must be closed for the function to be enabled. When the two input
wires (101 and 142) are ON, the TCM inhibits all neutral-to-range shifts. The inhibit remains in effect until either
of the two input wires change state to OFF, or transmission output speed exceeds a preset value. The TCM sets
DTC P071D if it detects the two input wires in two different states (ON or OFF) for longer than 120 seconds.
6–116
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P071D General Purpose Input Fault
Conditions for Running the DTC
The test is enabled by calibration.
Conditions for Setting the DTC
DTC P071D sets if the TCM detects wire 101 and wire 142 in different states for more than 120 seconds.
Actions Taken When the DTC Sets
When DTC P071D is active, the following conditions will occur:
•
The CHECK TRANS light is illuminated.
•
The TCM may illuminate SERVICE TRANS light based on OEM wiring. Refer to Appendix P, Dual
Input Auxiliary Function Range Inhibit.
•
DTC is stored in TCM history.
•
TCM allows Neutral-to-Range shifts.
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
•
DTC P071D indicates the two input wires for Auxiliary Function Range Inhibit (Special) are in different ON/
OFF states. The code can be caused by:
— Faulty wiring
— Faulty connections to the auxiliary equipment selector switch
— A faulty auxiliary equipment selector switch
— Faulty connection to the auxiliary equipment sense switch
— A faulty auxiliary equipment sense switch
— A faulty TCM.
•
Inspect the wiring for poor electrical connections at the TCM and auxiliary equipment switches. Look for the
following conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
•
The status of analog input wires 101 and 142 can be read on Allison DOC™ For PC–Service Tool.
Test Description
The numbers below refer to step numbers on the diagnostic table.
2. This step tests for an active DTC.
3. This step tests for status of analog input wires 101 and 142.
Copyright © 2005 General Motors Corp.
6–117
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P071D General Purpose Input Fault
Step
1
2
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
1.
2.
3.
4.
5.
Value(s)
Install the Allison DOC™ For PC–Service Tool.
Start the engine.
Record the failure records.
Clear the DTCs.
Operate the auxiliary equipment in accordance
with the vehicle manufacturer’s operating
instructions. Attempt to duplicate same operating
conditions observed in failure records.
Yes
Go to Step 2
Go to Step 3
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Go to
Diagnostic Aids
NOTE: This DTC indicates that the two input wires
for the auxiliary function range inhibit (special)
I/O function are in different states for longer than
120 seconds.
3
4
5
6–118
Did DTC P071D return?
1. Using Allison DOC™ For PC–Service Tool,
determine the states of input wires 101 and 142.
2. Inspect the input wiring, connectors, and switches
to determine why the input states are different.
Did you find and correct the problem?
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
Refer to TCM diagnostic procedure, Section 3–6.
Is Section 3–6 complete?
In order to verify your repair:
1. Clear the DTC.
2. Use Allison DOC™ For PC–Service Tool to
monitor Auxiliary Function Range Inhibit
(special) input wires.
3. Operate the auxiliary equipment in accordance
with the manufacturer’s operating instructions.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Go to Step 5
Go to Step 4
Go to Step 5
Begin the
diagnosis again.
Go to Step 1
System OK
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0721 Output Speed Sensor Circuit Performance
END VIEW OF
20-WAY CONNECTOR
END VIEW OF
80-WAY CONNECTOR
1
6
7
10
11
14
15
20
A
B
61
80
41
60
21
40
1
20
OUTPUT
SPEED
SENSOR
A
WIRE 160
Use twisted pairs of wires
OUTPUT SPEED HI
40
OUTPUT SPEED LO
TCM
B
WIRE 140
Current Resistance (Ohms) Former Resistance (Ohms)
Before January, 2006
January, 2006
200
250
SPEED SENSOR CIRCUITS
60
TEMP (˚F)
TEMP (˚C)
–40
–40
340
300
68
20
450
400
230
110
V09135.00.01
Circuit Description
Speed sensors are variable reluctance devices that convert mechanical motion to an AC voltage. Each sensor
consists of a wire coil wrapped around a pole piece that is adjacent to a permanent magnet. These elements are
contained in a housing that is mounted adjacent to a rotating ferrous member. Two signal wires extend from one
end of the housing and an exposed end of the pole piece is at the opposite end of the housing. The permanent
magnet produces lines of flux around the pole piece. As a ferrous object (a tooth on the tone wheel) approaches and
passes through the gap at the end of the pole piece, an AC voltage pulse is induced in the wire coil. The
Transmission Control Module (TCM) calculates the frequency of these AC pulses and converts it to a speed value.
The AC voltage generated varies from 150mV at low speed to 15V at high speed. The signal wires from the sensor
are formed as twisted pairs to cancel magnetically induced fields. The cable is also shielded to protect from
voltage-related fields. Using two-wire differential input at the TCM eliminates noise from other sources.
Copyright © 2005 General Motors Corp.
6–119
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0721 Output Speed Sensor Circuit Performance
Conditions for Running the DTC
•
The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater
than 9V and less than 32V (24V TCM).
•
Output speed is above 200 rpm.
•
Shift is complete and range attained is not neutral.
•
For fire truck vocation, pump not pumping.
Conditions for Setting the DTC
DTC P0721 is set when one of the following two conditions occur:
•
Unrealistic large changes in output speed. Failure is set if an unrealistic change in transmission output speed is
detected at or above 500 rpm for 0.15 seconds.
•
Noisy output speed. Noise is determined with two counters. A low counter is incremented when output speed
change is below 500 rpm for 80 samples. A high counter is incremented when output speed change is above
800 rpm. When both counters accumulate 5 events, a failure is set.
Actions Taken When the DTC Sets
When DTC P0721 is active, the following conditions will occur:
•
If failure occurs while in a forward range and a shift has been completed, the transmission will remain in the
current range.
•
If failure occurs while in a forward range and a shift is in progress, the transmission will return to the previous
range, except in post-shift state, then the transmission will continue to the commanded range.
•
DTC P0721 is stored in TCM history.
•
The CHECK TRANS light illuminates.
•
The TCM inhibits TCC engagement.
•
The TCM freezes shift adapts.
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
•
Inspect the wiring for poor electrical connections at the TCM and service brake switch. Look for the following
conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
•
You may have to drive the vehicle in order to experience a fault.
6–120
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
•
If the condition is intermittent, connect the Allison DOC™ For PC–Service Tool and observe the speed sensor
indicated by the code. If the signal is erratic, investigate and eliminate the following:
— Intermittent wiring connection
— Excessive vibration (driveline or engine torsionals)
— Irregular sensor gap (loose sensor, loose tone wheel, or damaged tone wheel).
•
Install a known good speed sensor and see if normal function is restored to rule out an internal short or open in
the sensor removed.
•
Check that the speed sensor wiring consists of twisted pairs at the rate of 12 to 16 twists per 300 mm. These
twists must extend the entire length of the wiring harness to within at least 50 mm of the speed sensor
connector.
•
Install a known good TCM, if available. If the DTC does not return, reinstall the old TCM to verify the repair.
Test Description
The numbers below refer to step numbers on the diagnostic table.
2. This step tests for proper ignition voltage.
3. This step tests for proper output speed sensor resistance at the OEM-side of the harness.
4. This step tests for output speed sensor resistance.
DTC P0721 Output Speed Sensor Circuit Performance
Step
1
2
3
4
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
1.
2.
3.
4.
5.
Install the Allison DOC™ For PC–Service Tool. 9–18V (12V TCM)
18–32V (24V TCM)
Start the engine.
Record the failure records.
Clear the DTCs.
Using Allison DOC™ For PC–Service Tool,
measure ignition voltage.
Is voltage within specified values?
1. Turn OFF the ignition.
Refer to Speed
Sensor Resistance
2. Disconnect the 80-way connector at the TCM.
Table 6–12
3. Using a DVOM, measure resistance between
terminal 40 and terminal 60 at the OEM-side of
the 80-way connector.
Is the speed sensor resistance within the specified
value?
1. Disconnect the wiring harness from the output
Refer to Speed
speed sensor.
Sensor Resistance
2. Using a DVOM, check the resistance between the
Table 6–12
speed sensor terminals.
Is the speed sensor resistance within the specified
value?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 2
Go to Step 3
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Resolve voltage
problems (refer to
DTC P0882 and
P0883)
Go to
Diagnostic Aids
Go to Step 4
Go to Step 5
Go to Step 6
6–121
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0721 Output Speed Sensor Circuit Performance (cont’d)
Step
5
6
7
Action
NOTE: The vehicle OEM has responsibility for
external wiring harness repairs. Harness repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Value(s)
Yes
Go to Step 7
Coordinate with the vehicle OEM to repair or
replace the vehicle wiring.
Is the repair complete?
Replace the output speed sensor (refer to appropriate
service manual).
Is replacement complete?
In order to verify your repair:
1. Clear the DTC.
2. Drive the vehicle under normal operating
conditions.
3. Use Allison DOC™ For PC–Service Tool to
monitor output speed sensor operation.
Did the DTC return?
No
Go to Step 7
Begin the
diagnosis again.
Go to Step 1
System OK
Table 6–12. Speed Sensor Temperature Resistance
Current Resistance (Ohms) Former Resistance (Ohms)
January, 2006
Before January, 2006
6–122
Temp ˚F
Temp ˚C
250
200
–40
–40
340
300
68
20
450
400
230
110
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0722 Output Speed Sensor Circuit No Signal
END VIEW OF
20-WAY CONNECTOR
END VIEW OF
80-WAY CONNECTOR
1
6
7
10
11
14
15
20
A
B
61
80
41
60
21
40
1
20
OUTPUT
SPEED
SENSOR
A
WIRE 160
Use twisted pairs of wires
OUTPUT SPEED HI
40
OUTPUT SPEED LO
TCM
B
WIRE 140
Current Resistance (Ohms) Former Resistance (Ohms)
Before January, 2006
January, 2006
200
250
SPEED SENSOR CIRCUITS
60
TEMP (˚F)
TEMP (˚C)
–40
–40
340
300
68
20
450
400
230
110
V09135.00.01
Circuit Description
Speed sensors are variable reluctance devices that convert mechanical motion to an AC voltage. Each sensor
consists of a wire coil wrapped around a pole piece that is adjacent to a permanent magnet. These elements are
contained in a housing that is mounted adjacent to a rotating ferrous member. Two signal wires extend from one
end of the housing and an exposed end of the pole piece is at the opposite end of the housing. The permanent
magnet produces lines of flux around the pole piece. As a ferrous object (a tooth of the tone wheel) approaches and
passes through the gap at the end of the pole piece, an AC voltage pulse is induced in the wire coil. The
Transmission Control Module (TCM) calculates the frequency of these AC pulses and converts it to a speed value.
The AC voltage generated varies from 150mV at low speed to 15V at high speed. The signal wires from the sensor
are formed as twisted pairs to cancel magnetically induced fields. The cable is also shielded to protect from
voltage-related fields. Using two-wire differential input at the TCM eliminates noise from other sources.
Copyright © 2005 General Motors Corp.
6–123
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0722 Output Speed Sensor Circuit No Signal
Conditions for Running the DTC
•
The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater
than 9V and less than 32V (24V TCM).
•
For fire truck vocation, pump not pumping.
•
For unrealistically large change in output speed test:
— Output speed is at or above 600 rpm for more than 1 second.
•
For low output speed test:
— Shifting complete
— Reverse-to-Neutral shift not in progress
— Engine is running
— No hydraulic default condition due to loss of ignition voltage
— Transmission fluid temperature greater than –1.1ºC (30ºF)
— Transmission turbine speed greater than or equal to 600 rpm
Conditions for Setting the DTC
DTC P0722 is set when one of the following three conditions occur:
•
Unrealistic large change in output speed. A failure pending is set if the TCM detects a change in output speed
of more than 600 rpm. A failure is set if range attained is Neutral.
•
Unrealistic low value in output speed. A failure pending is set if output speed is detected below 61 rpm.
— A failure is set when output speed is below 61 rpm in third, fourth, or fifth range for more than 1 second.
— A failure is also set when output speed is below 61 rpm in second range for more than one 1 second when
net engine torque is +/- 1 N·m or turbine speed is greater than 800 rpm.
Actions Taken When the DTC Sets
When DTC P0722 is active, the following conditions will occur:
•
If failure occurs while in a forward range and a shift has been completed, the transmission will remain in the
current range.
•
If failure occurs while in a forward range and a shift is in progress, the transmission will return to the previous
range, except in post-shift state, then the transmission will continue to the commanded range.
•
DTC P0722 is stored in TCM history.
•
The CHECK TRANS light illuminates.
•
The TCM freezes shift adapts (DNA).
•
The TCM inhibits TCC engagement.
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
6–124
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
Diagnostic Aids
•
Inspect the wiring for poor electrical connections at the TCM and service brake switch. Look for the following
conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
•
You may have to drive the vehicle in order to experience a fault.
•
If the condition is intermittent, connect the Allison DOC™ For PC–Service Tool and observe the speed sensor
indicated by the code. If the signal is erratic, investigate and eliminate the following:
— Intermittent wiring connection
— Excessive vibration (driveline or engine torsionals)
— Irregular sensor gap (loose sensor, loose tone wheel, or damaged tone wheel).
•
Install a known good speed sensor and see if normal function is restored to rule out an internal short or open in
the sensor removed.
•
Check that the speed sensor wiring consists of twisted pairs at the rate of 12 to 16 twists per 300 mm. These
twists must extend the entire length of the wiring harness to within at least 50 mm of the speed sensor
connector.
Test Description
The numbers below refer to step numbers on the diagnostic table.
2. This step tests ignition voltage.
3. This step tests for proper output speed sensor resistance at the OEM-side of the harness.
4. This step tests for output speed sensor resistance.
DTC P0722 Output Speed Sensor Circuit No Signal
Step
1
2
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
1.
2.
3.
4.
5.
Install the Allison DOC™ For PC–Service Tool. 9–18V (12V TCM)
18–32V (24V TCM)
Start the engine.
Record the failure records.
Clear the DTCs.
Using Allison DOC™ For PC–Service Tool,
measure ignition voltage.
Is voltage within specified values?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 2
Go to Step 3
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Resolve voltage
problems (refer to
DTC P0882 and
P0883)
6–125
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0722 Output Speed Sensor Circuit No Signal (cont’d)
Step
3
4
5
6
7
Action
1. Turn OFF the ignition.
2. Disconnect the 80-way connector at the TCM.
3. Using a DVOM, measure resistance between
terminal 40 and terminal 60 at the OEM-side of
the 80-way connector.
Is the speed sensor resistance within the specified
value?
1. Disconnect the wiring harness from the output
speed sensor.
2. Using a DVOM, check the resistance between the
speed sensor terminals.
Is the speed sensor resistance within the specified
value?
NOTE: The vehicle OEM has responsibility for all
external wiring harness repairs. Harness repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Value(s)
Refer to Speed
Sensor Resistance
Table 6–13
Yes
Go to
Diagnostic Aids
No
Go to Step 4
Refer to Speed
Sensor Resistance
Table 6–13
Go to Step 5
Go to Step 6
Go to Step 7
Coordinate with the vehicle OEM to repair or
replace the vehicle wiring.
Is the repair complete?
Replace the output speed sensor (refer to appropriate
service manual).
Is replacement complete?
In order to verify your repair:
1. Clear the DTC.
2. Drive the vehicle under normal operating
conditions.
3. Use Allison DOC™ For PC–Service Tool to
monitor output speed sensor operation.
Did the DTC return?
Go to Step 7
Begin the
diagnosis again.
Go to Step 1
System OK
Table 6–13. Speed Sensor Temperature Resistance
Current Resistance (Ohms) Former Resistance (Ohms)
January, 2006
Before January, 2006
6–126
Temp ˚F
Temp ˚C
250
200
–40
–40
340
300
68
20
450
400
230
110
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0726 Engine Speed Sensor Circuit Performance
END VIEW OF
20-WAY CONNECTOR
END VIEW OF
80-WAY CONNECTOR
1
6
7
10
11
14
15
20
A
B
61
80
41
60
21
40
1
20
ENGINE
SPEED
SENSOR
A
WIRE 159
59
ENGINE SPEED HI
TCM
B
WIRE 139
Current Resistance (Ohms) Former Resistance (Ohms)
Before January, 2006
January, 2006
200
250
39
ENGINE SPEED LO
TEMP (˚F)
TEMP (˚C)
–40
–40
SPEED SENSOR CIRCUITS
340
300
68
20
Use twisted pairs of wires
450
400
230
110
V09136.00.01
Circuit Description
Speed sensors are variable reluctance devices that convert mechanical motion to an AC voltage. Each sensor
consists of a wire coil wrapped around a pole piece that is adjacent to a permanent magnet. These elements are
contained in a housing that is mounted adjacent to a rotating ferrous member. Two signal wires extend from one
end of the housing and an exposed end of the pole piece is at the opposite end of the housing. The permanent
magnet produces lines of flux around the pole piece. As a ferrous object (a rib on torque converter impeller)
approaches and passes through the gap at the end of the pole piece, an AC voltage pulse is induced in the wire coil.
The Transmission Control Module (TCM) calculates the frequency of these AC pulses and converts it to a speed
value. The AC voltage generated varies from 150mV at low speed to 15V at high speed. The signal wires from the
sensor are formed as twisted pairs to cancel magnetically induced fields. The cable is also shielded to protect from
voltage-related fields. Using two-wire differential input at the TCM eliminates noise from other sources.
Copyright © 2005 General Motors Corp.
6–127
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0726 Engine Speed Sensor Circuit Performance
Conditions for Running the DTC
• The test is enabled by calibration.
• Engine speed is above 600 rpm.
• Shift is complete and range attained is not neutral.
Conditions for Setting the DTC
DTC P0726 is set when one of the following conditions occur:
•
Unrealistic large changes in engine speed. Failure is set if an unrealistic change in transmission engine speed is
detected at or above 600 rpm for 0.15 seconds.
•
Noisy engine speed. Noise is determined with two counters. A low counter is incremented when engine speed
change is below 650 rpm for 80 samples. A high counter is incremented when engine speed change is above
1050 rpm. When both counters accumulate 5 events, a failure is set.
Actions Taken When the DTC Sets
When DTC P0726 is active, the following conditions will occur:
• DTC P0726 is stored in TCM history.
• The TCM does not illuminate the CHECK TRANS light.
• The TCM defaults engine speed to turbine speed. Turbine speed is used to determine the missing engine speed.
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
• Inspect the wiring for poor electrical connections at the TCM and engine speed sensor. Look for the following
conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
• You may have to drive the vehicle in order to experience a fault.
• If the condition is intermittent, connect the Allison DOC™ For PC–Service Tool and observe the speed sensor
indicated by the code. If the signal is erratic, investigate and eliminate the following:
— Intermittent wiring connection
— Excessive vibration (driveline or engine torsionals)
— Irregular sensor gap (loose sensor, damaged torque converter ribs).
• Install a known good speed sensor and see if normal function is restored to rule out an internal short or open in
the sensor removed.
• Check that the speed sensor wiring consists of twisted pairs at the rate of 12 to 16 twists per 300 mm. These
twists must extend the entire length of the wiring harness to within at least 50 mm of the speed sensor
connector.
• Install a known good TCM, if available. If the DTC does not return, reinstall the old TCM to verify the repair.
6–128
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
Test Description
The numbers below refer to step numbers on the diagnostic table.
2. This step tests for proper ignition voltage.
3. This step tests for proper engine speed sensor resistance at the OEM-side of the harness.
4. This step tests for engine speed sensor resistance.
DTC P0726 Engine Speed Sensor Circuit Performance
Step
1
2
3
4
5
6
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
1.
2.
3.
4.
5.
Install the Allison DOC™ For PC–Service Tool. 9–18V (12V TCM)
18–32V (24V TCM)
Start the engine.
Record the failure records.
Clear the DTCs.
Using Allison DOC™ For PC–Service Tool,
measure ignition voltage.
Is voltage within specified values?
1. Turn OFF the ignition.
Refer to Speed
Sensor Resistance
2. Disconnect the 80-way connector at the TCM.
Table 6–14
3. Using a DVOM, measure resistance between
terminal 39 and terminal 59 at the OEM-side of
the 80-way connector.
Is the speed sensor resistance within the specified
value?
1. Disconnect the wiring harness from the output
Refer to Speed
speed sensor.
Sensor Resistance
2. Using a DVOM, measure the resistance between
Table 6–14
the speed sensor terminals.
Is the speed sensor resistance within the specified
value?
NOTE: The vehicle OEM has responsibility for all
external wiring harness repairs. Harness repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Coordinate with the vehicle OEM to repair or
replace the vehicle wiring.
Is the repair complete?
Replace the engine speed sensor (refer to service
manual).
Is replacement complete?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 2
Go to Step 3
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Resolve voltage
problems (refer to
DTC P0882 and
P0883)
Go to
Diagnostic Aids
Go to Step 4
Go to Step 5
Go to Step 6
Go to Step 7
Go to Step 7
6–129
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0726 Engine Speed Sensor Circuit Performance (cont’d)
Step
7
Action
In order to verify your repair:
1. Clear the DTC.
2. Drive the vehicle under normal operating
conditions.
3. Using Allison DOC™ For PC–Service Tool,
monitor engine speed sensor operation.
Did the DTC return?
Value(s)
Yes
Begin the
diagnosis again.
Go to Step 1
No
System OK
Table 6–14. Speed Sensor Temperature Resistance
Current Resistance (Ohms) Former Resistance (Ohms)
January, 2006
Before January, 2006
6–130
Temp ˚F
Temp ˚C
250
200
–40
–40
340
300
68
20
450
400
230
110
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0727 Engine Speed Sensor Circuit No Signal
END VIEW OF
20-WAY CONNECTOR
END VIEW OF
80-WAY CONNECTOR
1
6
7
10
11
14
15
20
A
B
61
80
41
60
21
40
1
20
ENGINE
SPEED
SENSOR
A
WIRE 159
59
ENGINE SPEED HI
39
ENGINE SPEED LO
TCM
B
WIRE 139
Current Resistance (Ohms) Former Resistance (Ohms)
Before January, 2006
January, 2006
200
250
TEMP (˚F)
TEMP (˚C)
–40
–40
SPEED SENSOR CIRCUITS
340
300
68
20
Use twisted pairs of wires
450
400
230
110
V09136.00.01
Circuit Description
Speed sensors are variable reluctance devices that convert mechanical motion to an AC voltage. Each sensor
consists of a wire coil wrapped around a pole piece that is adjacent to a permanent magnet. These elements are
contained in a housing that is mounted adjacent to a rotating ferrous member. Two signal wires extend from one
end of the housing and an exposed end of the pole piece is at the opposite end of the housing. The permanent
magnet produces lines of flux around the pole piece. As a ferrous object (a rib on the torque converter impeller)
approaches and passes through the gap at the end of the pole piece, an AC voltage pulse is induced in the wire coil.
The Transmission Control Module (TCM) calculates the frequency of these AC pulses and converts it to a speed
value. The AC voltage generated varies from 150mV at low speed to 15V at high speed. The signal wires from the
sensor are formed as twisted pairs to cancel magnetically induced fields. The cable is also shielded to protect from
voltage-related fields. Using two-wire differential input at the TCM eliminates noise from other sources.
Copyright © 2005 General Motors Corp.
6–131
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0727 Engine Speed Sensor Circuit No Signal
Conditions for Running the DTC
• The test is enabled by calibration.
•
For unrealistically low engine speed test:
— Turbine speed is at or above 400 rpm.
— The ignition key is in RUN.
Conditions for Setting the DTC
DTC P0727 is set when one of the following conditions occur:
•
Unrealistic large change in engine speed. A failure pending is set if the TCM detects a change in engine speed
of more than 1040 rpm.
•
Unrealistic low value in engine speed. A failure is set if engine speed is detected below 61 rpm for 4 seconds.
Actions Taken When the DTC Sets
When DTC P0727 is active, the following conditions will occur:
•
DTC P0727 is stored in TCM history.
•
The TCM does not illuminate the CHECK TRANS light.
•
The TCM defaults engine speed to turbine speed. Turbine speed is used to determine the missing engine speed.
•
The TCM inhibits torque converter clutch (TCC) momentarily.
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
• Inspect the wiring for poor electrical connections at the TCM and engine speed sensor. Look for the following
conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
• You may have to drive the vehicle in order to experience a fault.
•
•
•
If the condition is intermittent, connect the Allison DOC™ For PC–Service Tool and observe the speed sensor
indicated by the code. If the signal is erratic, investigate and eliminate the following:
— Intermittent wiring connection
— Excessive vibration (driveline or engine torsionals)
— Irregular sensor gap (loose sensor, damaged torque converter ribs).
Install a known good speed sensor and see if normal function is restored to rule out an internal short or open in
the sensor removed.
Inspect that the speed sensor wiring consists of twisted pairs at the rate of 12 to 16 twists per 300 mm. These
twists must extend the entire length of the wiring harness to within at least 50 mm of the speed sensor
connector.
6–132
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
Test Description
The numbers below refer to step numbers on the diagnostic table.
2. This step tests for proper ignition voltage.
3. This step tests for proper engine speed sensor resistance at the OEM-side of the harness.
4. This step tests for engine speed sensor resistance.
DTC P0727 Engine Speed Sensor Circuit No Signal
Step
1
2
3
4
5
6
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
1.
2.
3.
4.
5.
Install the Allison DOC™ For PC–Service Tool. 9–18V (12V TCM)
18–32V (24V TCM)
Start the engine.
Record the failure records.
Clear the DTCs.
Using Allison DOC™ For PC–Service Tool,
measure ignition voltage.
Is voltage within specified values?
1. Turn OFF the ignition.
Refer to Speed
Sensor Resistance
2. Disconnect the 80-way connector at the TCM.
Table 6–15
3. Using a DVOM, measure resistance between
terminal 39 and terminal 59 at the OEM-side of
the 80-way connector.
Is the speed sensor resistance within the specified
value?
1. Disconnect the wiring harness from the engine
Refer to Speed
speed sensor.
Sensor Resistance
2. Using a DVOM, measure the resistance between
Table 6–15
the speed sensor terminals.
Is the speed sensor resistance within the specified
value?
NOTE: The vehicle OEM has responsibility for all
external wiring harness repairs. Harness repairs
performed at Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Coordinate with the vehicle OEM to repair or
replace the vehicle wiring.
Is the repair complete?
Replace the engine speed sensor (refer to service
manual).
Is replacement complete?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 2
Go to Step 3
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Resolve voltage
problems (refer to
DTC P0882 and
P0883)
Go to
Diagnostic Aids
Go to Step 4
Go to Step 5
Go to Step 6
Go to Step 7
Go to Step 7
6–133
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0727 Engine Speed Sensor Circuit No Signal (cont’d)
Step
7
Action
In order to verify your repair:
1. Clear the DTC.
2. Drive the vehicle under normal operating
conditions.
3. Using Allison DOC™ For PC–Service Tool,
monitor engine speed sensor operation.
Did the DTC return?
Value(s)
Yes
Begin the
diagnosis again.
Go to Step 1
No
System OK
Table 6–15. Speed Sensor Temperature Resistance
Current Resistance (Ohms) Former Resistance (Ohms)
January, 2006
Before January, 2006
6–134
Temp ˚F
Temp ˚C
250
200
–40
–40
340
300
68
20
450
400
230
110
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0729 Incorrect 6th Gear Ratio
Refer to Sixth Range Hydraulic Schematic
Circuit Description
The Transmission Control Module (TCM) uses input from the turbine speed and the output speed sensors to
determine the current commanded steady state gear ratio. The TCM then compares the known gear ratio to the
calculated gear ratio for the current range.
Conditions for Running the DTC
• Hydraulic system is pressurized.
• No shift in progress.
• Hydraulic default condition not present.
• Output speed is above 200 rpm.
• Engine initialization or shutdown is not in progress.
Conditions for Setting the DTC
DTC P0729 sets during steady state condition when the calculated sixth gear ratio differs from the known sixth
gear ratio for more than 2 seconds.
Actions Taken When the DTC Sets
When DTC P0729 is active, the following conditions will occur:
• The TCM attempts to shift to fifth range. If unsuccessful, the TCM commands third range.
• While diagnostic response is active, the TCM ignores shift selector inputs.
• The CHECK TRANS light illuminates.
• DTC is stored in TCM history.
• The TCM inhibits TCC engagement.
• The TCM freezes shift adapts (DNA).
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
• You may have to clear the DTC and drive the vehicle in order to experience a fault. Use the data obtained from
failure records to determine transmission range and/or certain vehicle operating variables such as temperature,
run time, etc. This data can be useful in reproducing the failure mode where DTC was set.
• Incorrect ratio codes typically indicate mechanical problems with specific clutches for range indicated, i.e. C2
and C4 for sixth range.
• An incorrect ratio DTC may indicate a mechanically failed clutch control solenoid. Review the DTC
information for the specific solenoid.
• Output speed or turbine speed tone wheel damage may cause erratic speed sensor input allowing this code to set.
Test Description
The numbers below refer to step numbers on the diagnostic table.
2. This step tests for proper transmission fluid level.
3. This step tests for proper ignition voltage.
Copyright © 2005 General Motors Corp.
6–135
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
4.
5.
6.
7.
This step tests speed sensor readings.
This step tests for clutch slippage in sixth range.
This step tests for clutch pressure to range clutches.
This step tests for evidence of clutch failure.
DTC P0729 Incorrect 6th Gear Ratio
Step
1
.2
3
4
5
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
Perform the Fluid Check Procedure (refer to
Go to Step 3
appropriate mechanic’s tips).
Is the transmission fluid level correct?
1. Start the engine.
9–18V (12V TCM)
Go to Step 4
18–32V (24V TCM)
2. Record the DTC failure record data.
3. Using the Allison DOC™ For PC–Service Tool,
measure ignition voltage.
Is the voltage within the specified values?
1. Start the engine and drive the vehicle under
Watch for erratic
Go to the
normal operating conditions.
appropriate speed
speed sensor
sensor DTC
2. Using the Allison DOC™ For PC–Service Tool,
signals
monitor turbine, engine, and output speed sensor
readings.
Is speed sensor data erratic or are dropouts in signal
indicated?
Go to
WARNING: To help avoid injury or property
Diagnostic Aids
damage caused by sudden and unexpected
vehicle movement, do not start a stationary
stall test until you:
• Put the transmission in N (Neutral).
• Apply the parking brake and service brake.
• Chock the wheels and take any other steps
necessary to prevent the vehicle from
moving.
• Warn personnel to keep clear of the vehicle
and its path.
1. Start the engine.
2. Using Allison DOC™ For PC–Service Tool,
select the clutch test mode.
3. With brakes applied, select D (Drive).
4. With the engine at idle, select and attain the
range indicated by the DTC. Turbine speed
should go to zero.
5. Slowly increase engine speed to 1200 to
1500 rpm. Watch for turbine speed (turbine
speed should remain at zero).
Did turbine speed remain at zero?
6–136
Yes
Go to Step 2
Copyright © 2005 General Motors Corp.
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Go to Fluid Check
Procedure (refer to
mechanic’s tips)
Go to General
Troubleshooting
Section 8
Go to Step 5
Go to Step 6
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0729 Incorrect 6th Gear Ratio (cont’d)
Step
6
7
8
9
10
11
Action
1. Turn OFF the ignition.
2. Install 2000 kPa (300 psi) pressure gauges in
main pressure tap and C2 and C4 pressure taps.
3. Start the engine.
4. Using Allison DOC™ For PC–Service Tool,
select the clutch test mode.
5. With brakes applied, select and attain range
indicated by the DTC.
6. Read and record Main, C2, and C4 clutch
pressures.
Are the pressure readings within specified values in
Appendix B?
Remove the dipstick and inspect the transmission
fluid for clutch debris or burnt odor. If necessary,
drain a small amount of fluid for this inspection.
Are there signs of a clutch failure?
1. Consult the service manual and remove the
transmission hydraulic control module.
2. Inspect the control valve bodies for stuck or
sticking solenoid regulator valves and logic latch
valves.
3. Inspect the suction filter. Be sure screen is not
plugged.
4. Inspect for damaged gaskets and face seals.
Was a valve body problem found and repaired?
Using pressure readings obtained in Step 6, replace
the affected solenoid.
• Incorrect C2 pressure—PCS2
• Incorrect C4 pressure—PCS4
Value(s)
See Main and
Clutch Pressure
specifications in
Appendix B
Is the replacement complete?
Remove the main and lube filters and inspect for
clutch debris. It may also be necessary to remove the
control module and inspect the suction screen for
clutch debris.
If debris is found, remove the transmission for
overhaul or replacement (refer to the appropriate
service manual).
Is the replacement complete?
In order to verify your repair:
1. Clear the DTC.
2. Using Allison DOC™ For PC–Service Tool,
monitor engine, turbine, and output speed sensor
readings.
3. Drive the vehicle under normal operating
conditions.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 7
No
Go to Step 8
Go to Step 10
Go to
Diagnostic Aids
Go to Step 11
Go to Step 9
Go to Step 11
Go to Step 11
Begin the
diagnosis again.
Go to Step 1
System OK
6–137
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0731 Incorrect 1st Gear Ratio
Refer to First Range Hydraulic Schematic
Circuit Description
The Transmission Control Module (TCM) uses input from the turbine speed and the output speed sensors to
determine the current commanded steady state gear ratio. The TCM then compares the known gear ratio to the
calculated gear ratio for the current range.
Conditions for Running the DTC
•
Hydraulic system is pressurized.
•
No shift in progress.
•
Hydraulic default condition not present.
•
Output speed is above 200 rpm.
•
Engine initialization or shutdown is not in progress.
Conditions for Setting the DTC
DTC P0731 sets when the calculated first range ratio (steady state) differs from the known first range ratio.
Actions Taken When the DTC Sets
When DTC P0731 is active, the following conditions will occur:
•
•
•
•
•
•
The TCM attempts to shift to second range. If unsuccessful, the TCM will shift to fifth range.
While diagnostic response is active, the TCM ignores shift selector inputs.
The CHECK TRANS light illuminates.
DTC is stored in TCM history.
The TCM inhibits TCC engagement.
The TCM freezes shift adapts (DNA).
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
•
You may have to clear the DTC and drive the vehicle in order to experience a fault. Use the data obtained from
failure records to determine transmission range and/or certain vehicle operating variables such as temperature,
run time, etc. This data can be useful in reproducing the failure mode where DTC was set.
•
Incorrect ratio codes typically indicate mechanical problems with specific clutches for range indicated, i.e. C1
and C5 for first range.
•
An incorrect ratio DTC may indicate a mechanically failed clutch control solenoid. Review the DTC
information for the specific solenoid.
•
Incorrect TCM calibration will cause this DTC to set. Verify that the Calibration Identification Number (CIN)
is compatible with the model of transmission installed in the vehicle.
•
Output speed or turbine speed tone wheel damage may cause erratic speed sensor input allowing this code to
set.
6–138
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
Test Description
The numbers below refer to step numbers on the diagnostic table.
2. This step test for proper transmission fluid level.
3. This step tests for proper ignition voltage.
4. This step tests for proper match between calibration gear ratio and actual gear ratio.
5. This step tests speed sensor readings.
6. This step tests for clutch slippage in first range.
7. This step tests for clutch pressure to range clutches.
8. This step tests for evidence of clutch failure.
DTC P0731 Incorrect 1st Gear Ratio
Step
1
2
3
4
5
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Perform the Fluid Check Procedure (refer to
appropriate mechanic’s tips).
Is the transmission fluid level correct?
1. Start the engine.
2. Record the DTC failure record data.
3. Using the Allison DOC™ For PC–Service Tool,
measure ignition voltage.
Is the voltage within the specified values?
1. Start the engine, use the shift selector to hold in
first range, and drive the vehicle under normal
operating conditions.
2. Using the Allison DOC™ For PC–Service Tool,
read the Diagnostic Transmission Gear Ratio.
3. Compare the gear ratio shown on Allison DOC™
For PC–Service Tool with the actual gear ratio of
the transmission.
Is the TCM CIN correct for transmission model?
1. Start the engine and drive the vehicle under
normal operating conditions.
2. Using the Allison DOC™ For PC–Service Tool,
monitor turbine, engine, and output speed sensor
readings.
Is speed sensor data erratic or are dropouts in signal
indicated?
Value(s)
Yes
Go to Step 2
Go to Step 3
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Go to Fluid Check
Procedure (refer to
mechanic’s tips)
9–18V (12V TCM)
18–32V (24V TCM)
Go to Step 4
Go to General
Troubleshooting
Section 8
3000 Product
Family
Close ratio=3.49:1
Wide ratio= 4.59:1
Go to Step 5
Go to
Diagnostic Aids
Go to the
appropriate speed
sensor DTC
Go to Step 6
4000 Product
Family
Close ratio=3.51:1
Wide ratio= 4.70:1
Watch for erratic
speed sensor
signals
Copyright © 2005 General Motors Corp.
6–139
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0731 Incorrect 1st Gear Ratio (cont’d)
Step
6
7
8
9
6–140
Action
Value(s)
Yes
Go to
Diagnostic Aids
No
Go to Step 7
See Main and
Clutch Pressure
specifications in
Appendix B
Go to Step 8
Go to Step 9
Go to Step 11
Go to
Diagnostic Aids
Go to Step 12
Go to Step 10
WARNING: To help avoid injury or property
damage caused by sudden and unexpected
vehicle movement, do not start a stationary
stall test until you:
• Put the transmission in N (Neutral).
• Apply the parking brake and service brake.
• Chock the wheels and take any other steps
necessary to prevent the vehicle from
moving.
• Warn personnel to keep clear of the vehicle
and its path.
1. Start the engine.
2. Using Allison DOC™ For PC–Service Tool,
select the clutch test mode.
3. With brakes applied, select D (Drive).
4. With the engine at idle, select and attain the
range indicated by the DTC. Turbine speed
should go to zero.
5. Slowly increase engine speed to 1200 to
1500 rpm. Watch for turbine speed (turbine speed
should remain at zero).
Did turbine speed remain at zero?
1. Turn OFF the ignition.
2. Install 2000 kPa (300 psi) pressure gauges in
main pressure tap and C1 and C5 pressure taps.
3. Start the engine.
4. Using Allison DOC™ For PC–Service Tool,
select the clutch test mode.
5. With brakes applied, select and attain range
indicated by the DTC.
6. Read and record Main, C1, and C5 clutch
pressures.
Are the pressure readings within specified values in
Appendix B?
Remove the dipstick and inspect the transmission
fluid for clutch debris or burnt odor. If necessary,
drain a small amount of fluid for this inspection.
Are there signs of a clutch failure?
1. Consult the service manual and remove the
transmission hydraulic control module.
2. Inspect the control valve bodies for stuck or
sticking solenoid regulator valves and logic latch
valves.
3. Inspect the suction filter. Be sure screen is not
plugged.
4. Inspect for damaged gaskets and face seals.
Was a valve body problem found and repaired?
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0731 Incorrect 1st Gear Ratio (cont’d)
Step
10
11
12
Action
Using pressure readings obtained in Step 6, replace
the affected solenoid.
• Incorrect C1 pressure—PCS1
• Incorrect C5 pressure—PCS3
Value(s)
Is the replacement complete?
Remove the main and lube filters and inspect for
clutch debris. It may also be necessary to remove the
control module and inspect the suction screen for
clutch debris.
If debris is found, remove the transmission for
overhaul or replacement (refer to the appropriate
service manual).
Is the replacement complete?
In order to verify your repair:
1. Clear the DTC.
2. Using Allison DOC™ For PC–Service Tool,
monitor engine, turbine, and output speed sensor
readings.
3. Drive the vehicle under normal operating
conditions.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 12
No
Go to Step 12
Begin the
diagnosis again.
Go to Step 1
System OK
6–141
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0732 Incorrect 2nd Gear Ratio
Refer to Second Range Hydraulic Schematic
Circuit Description
The Transmission Control Module (TCM) uses input from the turbine speed and the output speed sensors to
determine the current commanded steady state gear ratio. The TCM then compares the known gear ratio to the
calculated gear ratio for the current range.
Conditions for Running the DTC
• Hydraulic system is pressurized.
•
No shift in progress.
•
Hydraulic default condition not present.
•
Output speed is above 200 rpm.
•
Engine initialization or shutdown is not in progress.
Conditions for Setting the DTC
DTC P0732 sets when the calculated second range ratio (steady state) differs from the known second range ratio.
Actions Taken When the DTC Sets
When DTC P0732 is active, the following conditions will occur:
•
The TCM will attempt to shift to third range. If unsuccessful, the TCM commands fifth range.
•
While diagnostic response is active, the TCM ignores shift selector inputs.
•
The CHECK TRANS light illuminates.
•
DTC is stored in TCM history.
•
The TCM inhibits TCC engagement.
•
The TCM freezes shift adapts (DNA).
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
• You may have to clear the DTC and drive the vehicle in order to experience a fault. Use the data obtained from
failure records to determine transmission range and/or certain vehicle operating variables such as temperature,
run time, etc. This data can be useful in reproducing failures mode where DTC was set.
•
Incorrect ratio codes typically indicate mechanical problems with specific clutches for range indicated, i.e. C1
and C4 for second range.
•
An incorrect ratio DTC may indicate a mechanically failed clutch control solenoid. Review the DTC
information for the specific solenoid.
•
Incorrect TCM calibration will cause this DTC to set. Verify that the Calibration Identification Number (CIN)
is compatible with the model of transmission installed in the vehicle.
•
Output speed or turbine speed tone wheel damage may cause erratic speed sensor input allowing this code to
set.
6–142
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
Test Description
The numbers below refer to step numbers on the diagnostic table.
2. This step tests for proper transmission fluid level.
3. This step tests for proper ignition voltage.
4. This step tests for proper match between calibration gear ratio and actual gear ratio.
5. This step tests speed sensor readings.
6. This step tests for clutch slippage in second range.
7. This step tests for clutch pressure to range clutches.
8. This step tests for evidence of clutch failure.
DTC P0732 Incorrect 2nd Gear Ratio
Step
1
2
3
4
5
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Perform the Fluid Check Procedure (refer to
appropriate mechanic’s tips).
Is the transmission fluid level correct?
1. Start the engine.
2. Record the DTC failure record data.
3. Using the Allison DOC™ For PC–Service Tool,
measure ignition voltage.
Is the voltage within the specified values?
1. Start the engine and drive the vehicle under
normal operating conditions in the range that sets
the code.
2. Use the shift selector to hold transmission in
second range.
3. Using the Allison DOC™ For PC–Service Tool,
read the Diagnostic Transmission Gear Ratio.
4. Compare the gear ratio shown on Allison DOC™
For PC–Service Tool with the actual gear ratio of
the transmission.
Is the TCM CIN correct for transmission model?
1. Start the engine and drive the vehicle under
normal operating conditions.
2. Using the Allison DOC™ For PC–Service Tool,
monitor turbine, engine, and output speed sensor
readings.
Is speed sensor data erratic or are dropouts in signal
indicated?
Value(s)
Yes
Go to Step 2
Go to Step 3
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Go to Fluid Check
Procedure (refer to
mechanic’s tips)
9–18V (12V TCM)
18–32V (24V TCM)
Go to Step 4
Go to General
Troubleshooting
Section 8
3000 Product
Family
Close ratio= 1.86:1
Wide ratio= 2.25:1
Go to Step 5
Go to
Diagnostic Aids
Go to the
appropriate speed
sensor DTC
Go to Step 6
4000 Product
Family
Close ratio= 1.91:1
Wide ratio= 2.21:1
Watch for erratic
speed sensor
signals
Copyright © 2005 General Motors Corp.
6–143
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0732 Incorrect 2nd Gear Ratio (cont’d)
Step
6
7
8
9
6–144
Action
Value(s)
Yes
Go to
Diagnostic Aids
No
Go to Step 7
See Main and
Clutch Pressure
specifications in
Appendix B
Go to Step 8
Go to Step 9
Go to Step 11
Go to
Diagnostic Aids
Go to Step 12
Go to Step 10
WARNING: To help avoid injury or property
damage caused by sudden and unexpected
vehicle movement, do not start a stationary
stall test until you:
• Put the transmission in N (Neutral).
• Apply the parking brake and service brake.
• Chock the wheels and take any other steps
necessary to prevent the vehicle from
moving.
• Warn personnel to keep clear of the vehicle
and its path.
1. Start the engine.
2. Using Allison DOC™ For PC–Service Tool,
select the clutch test mode.
3. With brakes applied, select D (Drive).
4. With the engine at idle, select and attain the
range indicated by the DTC. Turbine speed
should go to zero.
5. Slowly increase engine speed to 1200 to
1500 rpm. Watch for turbine speed (turbine speed
should remain at zero).
Did turbine speed remain at zero?
1. Turn OFF the ignition.
2. Install 2000 kPa (300 psi) pressure gauges in
main pressure tap and C1 and C4 pressure taps.
3. Start the engine.
4. Using Allison DOC™ For PC–Service Tool,
select the clutch test mode.
5. With brakes applied, select and attain range
indicated by the DTC.
6. Read and record Main, C1, and C4 clutch
pressures.
Are the pressure readings within specified values in
Appendix B?
Remove the dipstick and inspect the transmission
fluid for clutch debris or burnt odor. If necessary,
drain a small amount of fluid for this inspection.
Are there signs of a clutch failure?
1. Consult the service manual and remove the
transmission hydraulic control module.
2. Inspect the control valve bodies for stuck or
sticking solenoid regulator valves and logic latch
valves.
3. Inspect the suction filter. Be sure screen is not
plugged.
4. Inspect for damaged gaskets and face seals.
Was a valve body problem found and repaired?
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0732 Incorrect 2nd Gear Ratio (cont’d)
Step
10
11
12
Action
Using pressure readings obtained in Step 6, replace
the affected solenoid.
• Incorrect C1 pressure—PCS1
• Incorrect C4 pressure—PCS4
Value(s)
Is the replacement complete?
Remove the main and lube filters and inspect for
clutch debris. It may also be necessary to remove the
control module and inspect the suction screen for
clutch debris.
If debris is found, remove the transmission for
overhaul or replacement (refer to the appropriate
service manual).
Is the replacement complete?
In order to verify your repair:
1. Clear the DTC.
2. Using Allison DOC™ For PC–Service Tool,
monitor engine, turbine, and output speed sensor
readings.
3. Drive the vehicle under normal operating
conditions.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 12
No
Go to Step 12
Begin the
diagnosis again.
Go to Step 1
System OK
6–145
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0733 Incorrect 3rd Gear Ratio
Refer to Third Range Hydraulic Schematic
Circuit Description
The Transmission Control Module (TCM) uses input from the turbine speed and the output speed sensors to
determine the current commanded steady state gear ratio. The TCM then compares the known gear ratio to the
calculated gear ratio for the current range.
Conditions for Running the DTC
• Hydraulic system is pressurized.
•
No shift in progress.
•
Hydraulic default condition not present.
•
Output speed is above 200 rpm.
•
Engine initialization or shutdown is not in progress.
Conditions for Setting the DTC
DTC P0733 sets when the calculated third range ratio (steady state) differs from the known third range ratio.
Actions Taken When the DTC Sets
When DTC P0733 is active, the following conditions will occur:
•
The TCM attempts to shift to fourth range. If unsuccessful, the TCM commands sixth range.
•
While diagnostic response is active, the TCM ignores shift selector inputs.
•
The CHECK TRANS light illuminates.
•
DTC is stored in TCM history.
•
The TCM inhibits TCC engagement.
•
The TCM freezes shift adapts (DNA).
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
• You may have to clear the DTC and drive the vehicle in order to experience a fault. Use the data obtained from
failure records to determine transmission range and/or certain vehicle operating variables such as temperature,
run time, etc. This data can be useful in reproducing the failure mode where the DTC was set.
•
Incorrect ratio codes typically indicate mechanical problems with specific clutches for range indicated, i.e. C1
and C3 for third range.
•
An incorrect ratio DTC may indicate a mechanically failed clutch control solenoid. Review the DTC
information for the specific solenoid.
•
Incorrect TCM calibration will cause this DTC to set. Verify that the Calibration Identification Number (CIN)
is compatible with the model of transmission installed in vehicle.
•
Output speed or turbine speed tone wheel damage may cause erratic speed sensor input allowing this code to
set.
6–146
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
Test Description
The numbers below refer to step numbers on the diagnostic table.
2. This step tests for proper transmission fluid level.
3. This step tests for proper ignition voltage.
4. This step tests for proper match between calibration gear ratio and actual gear ratio.
5. This step tests speed sensor readings.
6. This step tests for clutch slippage in third range.
7. This step tests for clutch pressure to range clutches.
8. This step tests for evidence of clutch failure.
DTC P0733 Incorrect 3rd Gear Ratio
Step
1
2
3
4
5
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Perform the Fluid Check Procedure (refer to
appropriate mechanic’s tips).
Is the transmission fluid level correct?
1. Start the engine.
2. Record the DTC failure record data.
3. Using the Allison DOC™ For PC–Service Tool,
measure ignition voltage.
Is the voltage within the specified values?
1. Start the engine and drive the vehicle under
normal operating conditions.
2. Use the shift selector to hold transmission in third
range.
3. Using the Allison DOC™ For PC–Service Tool,
read the Diagnostic Transmission Gear Ratio.
4. Compare the gear ratio shown on Allison DOC™
For PC–Service Tool with the actual gear ratio of
the transmission.
Is the TCM CIN correct for transmission model?
1. Start the engine and drive the vehicle under
normal operating conditions.
2. Using the Allison DOC™ For PC–Service Tool,
monitor turbine, engine, and output speed sensor
readings.
Is speed sensor data erratic or are dropouts in signal
indicated?
Value(s)
Yes
Go to Step 2
Go to Step 3
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Go to Fluid Check
Procedure (refer to
mechanic’s tips)
9–18V (12V TCM)
18–32V (24V TCM)
Go to Step 4
Go to General
Troubleshooting
Section 8
3000 Product
Family
Close ratio= 1.41:1
Wide ratio= 1.54:1
Go to Step 5
Go to
Diagnostic Aids
Go to the
appropriate speed
sensor DTC
Go to Step 6
4000 Product
Family
Close ratio= 1.43:1
Wide ratio= 1.53:1
Watch for erratic
speed sensor
signals
Copyright © 2005 General Motors Corp.
6–147
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0733 Incorrect 3rd Gear Ratio (cont’d)
Step
6
7
8
9
6–148
Action
Value(s)
Yes
Go to
Diagnostic Aids
No
Go to Step 7
See Main and
Clutch Pressure
specifications in
Appendix B
Go to Step 8
Go to Step 9
Go to Step 11
Go to
Diagnostic Aids
Go to Step 12
Go to Step 10
WARNING: To help avoid injury or property
damage caused by sudden and unexpected
vehicle movement, do not start a stationary
stall test until you:
• Put the transmission in N (Neutral).
• Apply the parking brake and service brake.
• Chock the wheels and take any other steps
necessary to prevent the vehicle from
moving.
• Warn personnel to keep clear of the vehicle
and its path.
1. Start the engine.
2. Using Allison DOC™ For PC–Service Tool,
select the clutch test mode.
3. With brakes applied, select D (Drive).
4. With the engine at idle, select and attain the
range indicated by the DTC. Turbine speed
should go to zero.
5. Slowly increase engine speed to 1200 to
1500 rpm. Watch for turbine speed (turbine
speed should remain at zero).
Did turbine speed remain at zero?
1. Turn OFF the ignition.
2. Install 2000 kPa (300 psi) pressure gauges in
main pressure tap and C1 and C3 pressure taps.
3. Start the engine.
4. Using Allison DOC™ For PC–Service Tool,
select the clutch test mode.
5. With brakes applied, select and attain range
indicated by the DTC.
6. Read and record Main, C1, and C3 clutch
pressures.
Are the pressure readings within specified values in
Appendix B?
Remove the dipstick and inspect the transmission
fluid for clutch debris or burnt odor. If necessary,
drain a small amount of fluid for this inspection.
Are there signs of a clutch failure?
1. Consult the service manual and remove the
transmission hydraulic control module.
2. Inspect the control valve bodies for stuck or
sticking solenoid regulator valves and logic latch
valves.
3. Inspect the suction filter. Be sure screen is not
plugged.
4. Inspect for damaged gaskets and face seals.
Was a valve body problem found and repaired?
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0733 Incorrect 3rd Gear Ratio (cont’d)
Step
10
11
12
Action
Using pressure readings obtained in Step 6, replace
the affected solenoid.
• Incorrect C1 pressure—PCS1
• Incorrect C3 pressure—PCS3
Value(s)
Is the replacement complete?
Remove the main and lube filters and inspect for
clutch debris. It may also be necessary to remove the
control module and inspect the suction screen for
clutch debris.
If debris is found, remove the transmission for
overhaul or replacement (refer to the appropriate
service manual).
Is the replacement complete?
In order to verify your repair:
1. Clear the DTC.
2. Using Allison DOC™ For PC–Service Tool,
monitor engine, turbine, and output speed sensor
readings.
3. Drive the vehicle under normal operating
conditions.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 12
No
Go to Step 12
Begin the
diagnosis again.
Go to Step 1
System OK
6–149
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0734 Incorrect 4th Gear Ratio
Refer to Fourth Range Hydraulic Schematic
Circuit Description
The Transmission Control Module (TCM) uses input from the turbine speed and the output speed sensors to
determine the current commanded steady state gear ratio. The TCM then compares the known gear ratio to the
calculated gear ratio for the current range.
Conditions for Running the DTC
•
Hydraulic system is pressurized.
•
No shift in progress.
•
Hydraulic default condition not present.
•
Output speed is above 200 rpm.
•
Engine initialization or shutdown is not in progress.
Conditions for Setting the DTC
DTC P0734 sets when the calculated fourth range ratio (steady state) differs from the known fourth range ratio.
Actions Taken When the DTC Sets
When DTC P0734 is active, the following conditions will occur:
•
The TCM attempts to shift to fifth range. If unsuccessful, the TCM commands third range.
•
While diagnostic response is active, the TCM ignores shift selector inputs.
•
The CHECK TRANS light illuminates.
•
DTC is stored in TCM history.
•
The TCM inhibits TCC engagement.
•
The TCM freezes shift adapts (DNA).
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
•
You may have to clear the DTC and drive the vehicle in order to experience a fault. Use the data obtained from
failure records to determine transmission range and/or certain vehicle operating variables such as temperature,
run time, etc. This data can be useful in reproducing failures mode where DTC was set.
•
Incorrect ratio codes typically indicate mechanical problems with specific clutches for range indicated, i.e. C1
and C2 for fourth range.
•
An incorrect ratio DTC may indicate a mechanically failed clutch control solenoid. Review the DTC
information for the specific solenoid.
•
Output speed or turbine speed tone wheel damage may cause erratic speed sensor input allowing this code to
set.
6–150
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
Test Description
The numbers below refer to step numbers on the diagnostic table.
2.
3.
4.
5.
6.
7.
This step tests for proper transmission fluid level.
This step tests for proper ignition voltage.
This step tests speed sensor readings.
This step tests for clutch slippage in fourth range.
This step tests for clutch pressure to range clutches.
This step tests for evidence of clutch failure.
DTC P0734 Incorrect 4th Gear Ratio
Step
1
2
3
4
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
Yes
Go to Step 2
Perform the Fluid Check Procedure (refer to
Go to Step 3
appropriate mechanic’s tips).
Is the transmission fluid level correct?
1. Start the engine.
9–18V (12V TCM)
Go to Step 4
18–32V
(24V
TCM)
2. Record the DTC failure record data.
3. Using the Allison DOC™ For PC–Service Tool,
measure ignition voltage.
Is the voltage within the specified values?
1. Start the engine and drive the vehicle under
Watch for erratic
Go to the
normal operating conditions.
appropriate speed
speed sensor
sensor DTC
2. Using the Allison DOC™ For PC–Service Tool,
signals
monitor turbine, engine, and output speed sensor
readings.
Is speed sensor data erratic or are dropouts in signal
indicated?
Copyright © 2005 General Motors Corp.
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Go to Fluid Check
Procedure (refer to
mechanic’s tips)
Go to General
Troubleshooting
Section 8
Go to Step 5
6–151
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0734 Incorrect 4th Gear Ratio (cont’d)
Step
5
6
7
8
6–152
Action
Value(s)
Yes
Go to
Diagnostic Aids
No
Go to Step 6
See Main and
Clutch Pressure
specifications in
Appendix B
Go to Step 7
Go to Step 8
Go to Step 10
Go to
Diagnostic Aids
Go to Step 10
Go to Step 9
WARNING: To help avoid injury or property
damage caused by sudden and unexpected
vehicle movement, do not start a stationary
stall test until you:
• Put the transmission in N (Neutral).
• Apply the parking brake and service brake.
• Chock the wheels and take any other steps
necessary to prevent the vehicle from
moving.
• Warn personnel to keep clear of the vehicle
and its path.
1. Start the engine.
2. Using Allison DOC™ For PC–Service Tool,
select the clutch test mode.
3. With brakes applied, select D (Drive).
4. With the engine at idle, select and attain the
range indicated by the DTC. Turbine speed
should go to zero.
5. Slowly increase engine speed to 1200 to
1500 rpm. Watch for turbine speed (turbine
speed should remain at zero).
Did turbine speed remain at zero?
1. Turn OFF the ignition.
2. Install 2000 kPa (300 psi) pressure gauges in
main pressure tap and C1 and C2 pressure taps.
3. Start the engine.
4. Using Allison DOC™ For PC–Service Tool,
select the clutch test mode.
5. With brakes applied, select and attain range
indicated by the DTC.
6. Read and record Main, C1, and C2 clutch
pressures.
Are the pressure readings within specified values in
Appendix B?
Remove the dipstick and inspect the transmission
fluid for clutch debris or burnt odor. If necessary,
drain a small amount of fluid for this inspection.
Are there signs of a clutch failure?
1. Consult the service manual and remove the
transmission hydraulic control module.
2. Inspect the control valve bodies for stuck or
sticking solenoid regulator valves and logic latch
valves.
3. Inspect the suction filter. Be sure screen is not
plugged.
4. Inspect for damaged gaskets and face seals.
Was a valve body problem found and repaired?
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0734 Incorrect 4th Gear Ratio (cont’d)
Step
9
10
11
Action
Using pressure readings obtained in Step 6, replace
the affected solenoid.
• Incorrect C1 pressure—PCS1
• Incorrect C2 pressure—PCS2
Value(s)
Is the replacement complete?
Remove the main and lube filters and inspect for
clutch debris. It may also be necessary to remove the
control module and inspect the suction screen for
clutch debris.
If debris is found, remove the transmission for
overhaul or replacement (refer to the appropriate
service manual).
Is the replacement complete?
In order to verify your repair:
1. Clear the DTC.
2. Using Allison DOC™ For PC–Service Tool,
monitor engine, turbine, and output speed sensor
readings.
3. Drive the vehicle under normal operating
conditions.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 11
No
Go to Step 11
Begin the
diagnosis again.
Go to Step 1
System OK
6–153
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0735 Incorrect 5th Gear Ratio
Refer to Fifth Range Hydraulic Schematic
Circuit Description
The Transmission Control Module (TCM) uses input from the turbine speed and the output speed sensors to
determine the current commanded steady state gear ratio. The TCM then compares the known gear ratio to the
calculated gear ratio for the current range.
Conditions for Running the DTC
•
Hydraulic system is pressurized.
•
No shift in progress.
•
Hydraulic default condition not present.
•
Output speed is above 200 rpm.
•
Engine initialization or shutdown is not in progress.
Conditions for Setting the DTC
DTC P0735 sets when the calculated fifth range ratio (steady state) differs from the known fifth range ratio.
Actions Taken When the DTC Sets
When DTC P0735 is active, the following conditions will occur:
•
The TCM attempts to shift to sixth range. If unsuccessful, the TCM will attempt to shift to third range. If
unsuccessful, the TCM commands second range.
•
While diagnostic response is active, the TCM ignores shift selector inputs.
•
The CHECK TRANS light illuminates.
•
DTC is stored in TCM history.
•
The TCM inhibits TCC engagement.
•
The TCM freezes shift adapts (DNA).
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
•
You may have to clear the DTC and drive the vehicle in order to experience a fault. Use the data obtained from
failure records to determine transmission range and/or certain vehicle operating variables such as temperature,
run time, etc. This data can be useful in reproducing the failure mode where the DTC was set.
•
Incorrect ratio codes typically indicate mechanical problems with specific clutches for range indicated, i.e. C2
and C3 for fifth range.
•
An incorrect ratio DTC may indicate a mechanically failed clutch control solenoid. Review the DTC
information for the specific solenoid.
•
Output speed or turbine speed tone wheel damage may cause erratic speed sensor input allowing this code to
set.
6–154
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
Test Description
The numbers below refer to step numbers on the diagnostic table.
2. This step tests for proper transmission fluid level.
3. This step tests for proper ignition voltage.
4. This step tests speed sensor readings.
5. This step tests for clutch slippage in fifth range.
6. This step tests for clutch pressure to range clutches.
7. This step tests for evidence of clutch failure.
DTC P0735 Incorrect 5th Gear Ratio
Step
1
2
3
4
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
Yes
Go to Step 2
Perform the Fluid Check Procedure (refer to
Go to Step 3
appropriate mechanic’s tips).
Is the transmission fluid level correct?
1. Start the engine.
9–18V (12V TCM)
Go to Step 4
18–32V (24V TCM)
2. Record the DTC failure record data.
3. Using the Allison DOC™ For PC–Service Tool,
measure ignition voltage.
Is the voltage within the specified values?
1. Start the engine and drive the vehicle under
Watch for erratic
Go to the
normal operating conditions.
appropriate speed
speed sensor
sensor DTC
2. Using the Allison DOC™ For PC–Service Tool,
signals
monitor turbine, engine, and output speed sensor
readings.
Is speed sensor data erratic or are dropouts in signal
indicated?
Copyright © 2005 General Motors Corp.
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Go to Fluid Check
Procedure (refer to
mechanic’s tips)
Go to General
Troubleshooting
Section 8
Go to Step 5
6–155
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0735 Incorrect 5th Gear Ratio (cont’d)
Step
5
6
7
8
6–156
Action
Value(s)
Yes
Go to
Diagnostic Aids
No
Go to Step 6
See Main and
Clutch Pressure
specifications in
Appendix B
Go to Step 7
Go to Step 8
Go to Step 10
Go to
Diagnostic Aids
Go to Step 11
Go to Step 9
WARNING: To help avoid injury or property
damage caused by sudden and unexpected
vehicle movement, do not start a stationary
stall test until you:
• Put the transmission in N (Neutral).
• Apply the parking brake and service brake.
• Chock the wheels and take any other steps
necessary to prevent the vehicle from
moving.
• Warn personnel to keep clear of the vehicle
and its path.
1. Start the engine.
2. Using Allison DOC™ For PC–Service Tool,
select the clutch test mode.
3. With brakes applied, select D (Drive).
4. With the engine at idle, select and attain the range
indicated by the DTC. Turbine speed should go to
zero.
5. Slowly increase engine speed to 1200 to
1500 rpm. Watch for turbine speed (turbine
speed should remain at zero).
Did turbine speed remain at zero?
1. Turn OFF the ignition.
2. Install 2000 kPa (300 psi) pressure gauges in
main pressure tap and C2 and C3 pressure taps.
3. Start the engine.
4. Using Allison DOC™ For PC–Service Tool,
select the clutch test mode.
5. With brakes applied, select and attain range
indicated by the DTC.
6. Read and record Main, C2, and C3 clutch
pressures.
Are the pressure readings within specified values in
Appendix B?
Remove the dipstick and inspect the transmission
fluid for clutch debris or burnt odor. If necessary,
drain a small amount of fluid for this inspection.
Are there signs of a clutch failure?
1. Consult the service manual and remove the
transmission hydraulic control module.
2. Inspect the control valve bodies for stuck or
sticking solenoid regulator valves and logic latch
valves.
3. Inspect the suction filter. Be sure screen is not
plugged.
4. Inspect for damaged gaskets and face seals.
Was a valve body problem found and repaired?
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0735 Incorrect 5th Gear Ratio (cont’d)
Step
9
10
11
Action
Using pressure readings obtained in Step 6, replace
the affected solenoid.
• Incorrect C2 pressure—PCS2
• Incorrect C3 pressure—PCS3
Value(s)
Is the replacement complete?
Remove the main and lube filters and inspect for
clutch debris. It may also be necessary to remove the
control module and inspect the suction screen for
clutch debris.
If debris is found, remove the transmission for
overhaul or replacement (refer to the appropriate
service manual).
Is the replacement complete?
In order to verify your repair:
1. Clear the DTC.
2. Using Allison DOC™ For PC–Service Tool,
monitor engine, turbine, and output speed sensor
readings.
3. Drive the vehicle under normal operating
conditions.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 11
No
Go to Step 11
Begin the
diagnosis again.
Go to Step 1
System OK
6–157
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0736 Incorrect Reverse Gear Ratio
Refer to Reverse Range Hydraulic Schematic
Circuit Description
The Transmission Control Module (TCM) uses input from the turbine speed and the output speed sensors to
determine the current commanded steady state gear ratio. The TCM then compares the known gear ratio to the
calculated gear ratio for the current range.
Conditions for Running the DTC
•
Hydraulic system is pressurized.
•
No shift in progress.
•
Hydraulic default condition not present.
•
Output speed is above 200 rpm.
•
Engine initialization or shutdown is not in progress.
Conditions for Setting the DTC
DTC P0736 sets when the calculated reverse range ratio (steady state) differs from the known reverse range ratio.
Actions Taken When the DTC Sets
When DTC P0736 is active, the following conditions will occur:
•
The TCM will lock in N (Neutral).
•
The CHECK TRANS light illuminates.
•
DTC is stored in TCM history.
•
The TCM inhibits TCC engagement.
•
The TCM freezes shift adapts (DNA).
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
•
You may have to clear the DTC and drive the vehicle in order to experience a fault. Use the data obtained from
failure records to determine transmission range and/or certain vehicle operating variables such as temperature,
run time, etc. This data can be useful in reproducing the failure mode where the DTC was set.
•
Incorrect ratio codes typically indicate mechanical problems with specific clutches for range indicated, i.e. C3
and C5 for reverse range.
•
An incorrect ratio DTC may indicate a mechanically failed clutch control solenoid. Review the DTC
information for the specific solenoid.
6–158
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
Test Description
The numbers below refer to step numbers on the diagnostic table.
2. This step tests for proper transmission fluid level.
3. This step tests for proper ignition voltage.
4. This step tests for proper match between calibration gear ratio and actual gear ratio.
5. This step tests speed sensor readings.
6. This step tests for clutch slippage in Reverse.
7. This step tests for clutch pressure to range clutches.
8. This step tests for evidence of clutch failure.
DTC P0736 Incorrect Reverse Ratio
Step
1
2
3
4
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
Yes
Go to Step 2
Perform the Fluid Check Procedure (refer to
Go to Step 3
appropriate mechanic’s tips).
Is the transmission fluid level correct?
1. Start the engine.
9–18V (12V TCM)
Go to Step 4
18–32V (24V TCM)
2. Record the DTC failure record data.
3. Using the Allison DOC™ For PC–Service Tool,
measure ignition voltage.
Is the voltage within the specified values?
1. Start the engine and drive the vehicle under
Watch for erratic
Go to the
normal operating conditions.
appropriate speed
speed sensor
sensor DTC
2. Using the Allison DOC™ For PC–Service Tool,
signals
monitor turbine, engine, and output speed sensor
readings.
Is speed sensor data erratic or are dropouts in signal
indicated?
Copyright © 2005 General Motors Corp.
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Go to Fluid Check
Procedure (refer to
mechanic’s tips)
Go to General
Troubleshooting
Section 8
Go to Step 5
6–159
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0736 Incorrect Reverse Ratio (cont’d)
Step
5
Action
Value(s)
Yes
Go to
Diagnostic Aids
No
Go to Step 6
See Main and
Clutch Pressure
specifications in
Appendix B
Go to Step 7
Go to Step 8
Go to Step 10
Go to
Diagnostic Aids
Go to Step 11
Go to Step 9
WARNING: To help avoid injury or property
damage caused by sudden and unexpected
vehicle movement, do not start a stationary
stall test until you:
• Put the transmission in N (Neutral).
• Apply the parking brake and service brake.
• Chock the wheels and take any other steps
necessary to prevent the vehicle from
moving.
• Warn personnel to keep clear of the vehicle
and its path.
CAUTION: DO NOT conduct a stall test in
Reverse. The torque produced in Reverse can
damage the vehicle.
1. Turn OFF the ignition.
2. Install 2000 kPa (300 psi) pressure gauges in
main pressure tap and C3 and C5 pressure taps.
3. Start the engine.
4. Using Allison DOC™ For PC–Service Tool,
select the clutch test mode.
5. With brakes applied, select R (Reverse).
6. With the engine at idle speed, select and attain
the range indicated by the DTC. Turbine speed
should go to zero.
6
7
8
6–160
Did turbine speed remain at zero?
Read and record Main, C3 and C5 clutch pressures.
Are the pressure readings within specified values in
Appendix B?
Remove the dipstick and inspect the transmission
fluid for clutch debris or burnt odor. If necessary,
drain a small amount of fluid for this inspection.
Are there signs of a clutch failure?
1. Consult the service manual and remove the
transmission hydraulic control module.
2. Inspect the control valve bodies for stuck or
sticking solenoid regulator valves and logic latch
valves.
3. Inspect the suction filter. Be sure screen is not
plugged.
4. Inspect for damaged gaskets and face seals.
Was a valve body problem found and repaired?
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0736 Incorrect Reverse Ratio (cont’d)
Step
9
10
11
Action
Using pressure readings obtained in Step 6, replace
the affected solenoid.
• Incorrect C3 pressure—PCS2
• Incorrect C5 pressure—PCS3
Value(s)
Is the replacement complete?
Remove the main and lube filters and inspect for
clutch debris. It may also be necessary to remove the
control module and inspect the suction screen for
clutch debris.
If debris is found, remove the transmission for
overhaul or replacement (refer to the appropriate
service manual).
Is the replacement complete?
In order to verify your repair:
1. Clear the DTC.
2. Using Allison DOC™ For PC–Service Tool,
monitor engine, turbine, and output speed sensor
readings.
3. Drive the vehicle under normal operating
conditions.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 11
No
Go to Step 11
Begin the
diagnosis again.
Go to Step 1
System OK
6–161
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0741 Torque Converter Clutch System Stuck Off
Refer to Hydraulic Schematic
Circuit Description
The Transmission Control Module (TCM) uses data from the engine speed sensor and the turbine speed sensor to
calculate torque converter slip value. The TCM then compares this calculated slip value to a preset value in the
TCM calibration.
Conditions for Running the DTC
•
The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater
than 9V and less than 32V (24V TCM).
•
Engine speed is greater than 200 rpm and less than 7500 rpm.
•
Selected range is a forward range.
•
Throttle position is above 75 percent.
•
Transmission fluid temperature is between 25ºC (77ºF) and 130ºC (266ºF).
•
6 seconds or more have elapsed since torque converter clutch (TCC) was applied in a range.
Conditions for Setting the DTC
DTC P0741 sets when the TCM detects a TCC slip value greater than 150 rpm for more than 25.5 seconds,
indicating TCC did not apply.
Actions Taken When the DTC Sets
When DTC P0741 is active, the following conditions will occur:
•
DTC is stored in TCM history.
•
The CHECK TRANS light illuminates.
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
Residue or contamination may cause solenoid regulator (spool) valves to stick intermittently.
Test Description
The numbers below refer to step numbers on the diagnostic table.
2. This step tests converter slip speed.
3. This step tests if TCC is being commanded ON.
4. This step tests for hydraulic pressure in lockup clutch circuit.
6–162
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0741 Torque Converter Clutch System Stuck Off
Step
1
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
Yes
Go to Step 2
2
1. Install the Allison DOC™ For PC–Service Tool.
>150 rpm
Go to Step 3
2. Turn ON the ignition. leave the engine OFF.
3.
4.
5.
6.
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Go to
Diagnostic Aids
Record the failure records.
Clear the DTC.
Drive the vehicle.
Using Allison DOC™ For PC–Service Tool,
monitor TCC slip speed when a range is attained
where the TCC should be applied.
NOTE: This DTC sets when converter slip speed is
detected above 150 rpm for 25.6 seconds or more.
This indicates the TCC has not applied.
3
4
5
6
Is the slip speed value at or above the specified value
when the TCC should be applied.
Monitor TCC solenoid state when converter slip
speed is greater than 150 rpm.
Is the TCC solenoid ON?
1. Turn OFF the ignition.
See Lockup Clutch
Pressure
2. Install 2000 kPa (300 psi) pressure gauge in the
lockup pressure tap.
specifications in
Appendix B
3. Drive the vehicle under normal operating
conditions.
4. Using Allison DOC™ For PC–Service Tool,
monitor TCC slip speed.
5. Read and record lockup pressure when TCC slip
speed is greater than 150 rpm.
Is lockup pressure reading within specified values in
Appendix B?
1. Consult the appropriate service manual and
remove the transmission hydraulic control
module.
2. Inspect the solenoid control valve body for a
stuck or sticking TCC solenoid regulator valve.
3. Inspect the suction filter. Be sure screen is not
plugged.
4. Inspect for damaged gaskets.
Was a valve body problem found and repaired?
Replace the TCC solenoid.
Is replacement complete?
Copyright © 2005 General Motors Corp.
Go to Step 4
Go to General
Troubleshooting
Section 8
Go to Step 7
Go to Step 5
Go to Step 8
Go to Step 6
Go to Step 8
6–163
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0741 Torque Converter Clutch System Stuck Off (cont’d)
Step
7
8
6–164
Action
1. Remove the transmission (refer to the appropriate
service manual).
2. Disassemble and inspect the torque converter.
3. Inspect for worn lockup clutch damper friction
material, damaged seals, etc.
Is the repair complete?
In order to verify your repair:
1. Clear the DTC.
2. Using Allison DOC™ For PC–Service Tool,
monitor converter slip speed.
3. Drive the vehicle under conditions noted in
failure records.
Did the DTC return?
Value(s)
Copyright © 2005 General Motors Corp.
Yes
Go to Step 8
No
Begin the
diagnosis again.
Go to Step 1
System OK
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0776 Pressure Control Solenoid 2 Stuck Off
Refer to Hydraulic Schematic
Circuit Description
The Transmission Control Module (TCM) uses input from the turbine speed and the output speed sensors to detect
if a clutch is slipping. Pressure Control Solenoid 2 (PCS2) supplies hydraulic pressure to the C3 clutch in reverse
and to the C2 clutch in fourth through sixth range. The TCM sets a DTC P0776 when it detects a slip condition
while PCS2 is supplying hydraulic pressure to the oncoming clutch.
Conditions for Running the DTC
•
Hydraulic system is pressurized.
•
Output speed greater than or equal to 125 rpm.
•
Turbine speed greater than or equal to 60 rpm.
•
Cold Mode operation not required.
Conditions for Setting the DTC
DTC P0776 sets when the TCM detects an incorrect oncoming ratio (range-to-range) for an accumulated number
of occurrences.
Actions Taken When the DTC Sets
•
When DTC P0776 occurs, the TCM will command the previous range.
•
While diagnostic response is active, the TCM ignores shift selector inputs.
•
The CHECK TRANS light illuminates.
•
DTC is stored in TCM history.
•
The TCM inhibits TCC engagement.
•
The TCM freezes shift adapts (DNA).
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
•
This DTC indicates the oncoming clutch being controlled by PCS2 is not applied or applied too slowly.
Common causes include:
— Erratic turbine or output speed signals.
— A leak or obstruction in a specific clutch apply circuit.
— A defective PCS2 solenoid.
— A stuck PCS2 regulator valve.
— A stuck C2 logic latch valve.
•
PCS2 supplies hydraulic pressure to the C3 clutch in reverse and to the C2 clutch in fourth range through sixth
range. Review the Allison DOC™ For PC–Service Tool failure record data for previous or current range
information when the DTC was set to determine which clutch circuit is suspect.
Copyright © 2005 General Motors Corp.
6–165
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
•
If the condition is intermittent, connect Allison DOC™ For PC–Service Tool and observe the speed sensor
indicated by the code. If the signal is erratic, investigate and eliminate the following:
— Intermittent wiring connection
— Excessive vibration (driveline or engine torsionals)
— Irregular sensor gap (loose sensor, loose tone wheel, or damaged tone wheel).
Test Description
The numbers below refer to step numbers on the diagnostic table.
2. This step tests for proper transmission fluid level.
3. This step tests for active diagnostic codes.
4. This step tests ignition voltage.
5. This step tests speed sensor readings.
6. This step tests for C2 and C3 clutch pressure from PCS2.
7. This step tests for evidence of clutch failure.
8. This step tests for stuck or sticking valves and damaged valve body gaskets.
DTC P0776 Pressure Control Solenoid 2 Stuck Off
Step
1
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
2
Perform the Fluid Check Procedure (refer to
appropriate mechanic’s tips).
Is the transmission fluid level correct?
1. Install Allison DOC™ For PC–Service Tool.
2. Turn ON the ignition, leave engine OFF.
3. Record the failure records.
4. Clear the DTC.
5. Drive the vehicle. Attempt to duplicate same
operating conditions observed in failure record.
3
Value(s)
Yes
Go to Step 2
Go to Step 3
Go to Step 4
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Go to Fluid Check
Procedure (refer to
mechanic’s tips)
Go to
Diagnostic Aids
NOTE: This DTC indicates that the TCM has
detected a slip condition and could not verify the
correct oncoming ratio following a shift.
4
5
6–166
Did DTC P0776 return?
1. Install the Allison DOC™ For PC–Service Tool. 9–18V (12V TCM)
Go to Step 5
18–32V (24V TCM)
2. Start the engine.
3. Record the DTC failure record data.
4. Using the Allison DOC™ For PC–Service Tool,
measure ignition voltage.
Is the voltage within the specified value?
1. Start the engine and drive the vehicle under
Watch for erratic
Go to the
normal operating conditions.
appropriate speed
speed sensor
sensor DTC
2. Using Allison DOC™ For PC–Service Tool,
signals
monitor turbine, engine, and output speed sensor
readings using the strip chart display.
Is speed sensor data erratic or are dropouts in signal
indicated?
Copyright © 2005 General Motors Corp.
Go to General
Troubleshooting
Section 8
Go to Step 6
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0776 Pressure Control Solenoid 2 Stuck Off (cont’d)
Step
6
7
8
9
10
11
Action
1. Turn OFF the ignition.
2. Install 2000 kPa (300 psi) pressure gauges in
main, C2, and C3 pressure taps.
3. Start the engine.
4. Using Allison DOC™ For PC–Service Tool,
select the clutch test mode.
5. With brakes applied, select and attain the range
where the DTC occurred as indicated in the
Failure Records.
6. Read and record Main and C2 and C3 clutch
pressures.
Are the pressure readings within specified values in
Appendix B?
Remove the dipstick and inspect the transmission
fluid for clutch debris or burnt odor. If necessary,
drain a small amount of fluid for this inspection.
Are there signs of a clutch failure?
1. Consult the service manual and remove the
transmission hydraulic control module.
2. Inspect the control valve bodies for stuck or
sticking solenoid regulator valves and logic latch
valves.
3. Inspect the suction filter. Be sure screen is not
plugged.
4. Inspect for damaged gaskets and face seals.
Was a valve body problem found and repaired?
Replace PCS2.
Is the replacement complete?
Remove the main and lube filters and inspect for
clutch debris. It may also be necessary to remove the
control module and inspect the suction screen for
clutch debris.
If debris is found, remove the transmission for
overhaul or replacement (refer to the appropriate
service manual).
Is the replacement complete?
Value(s)
Refer to Main and
Clutch Pressure
specifications in
Appendix B
In order to verify your repair:
1. Clear the DTC.
2. Using Allison DOC™ For PC–Service Tool,
monitor engine, turbine, and output speed sensor
readings.
3. Drive the vehicle under normal operating
conditions.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 7
No
Go to Step 8
Go to Step 10
Go to
Diagnostic Aids
Go to Step 11
Go to Step 9
Go to Step 11
Go to Step 11
Begin the
diagnosis again.
Go to Step 1
System OK
6–167
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0777 Pressure Control Solenoid 2 Stuck On
Refer to Hydraulic Schematic
Circuit Description
The Transmission Control Module (TCM) uses information from the turbine and output speed sensors to detect if a
clutch is in a tie-up condition or if three clutches are applied. Pressure Control Solenoid 2 (PCS2) supplies
hydraulic pressure to the C3 clutch in reverse and to the C2 clutch in fourth range through sixth range. The TCM
sets a DTC P0777 when it detects a tie-up condition while PCS2 is supplying hydraulic pressure to the off-going
clutch.
Conditions for Running the DTC
• Hydraulic system is pressurized.
•
Output speed greater than or equal to 200 rpm.
•
Turbine speed greater than or equal to 200 rpm.
•
Cold Mode operation not required.
Conditions for Setting the DTC
DTC P0777 sets when the transmission is shifting from range to range and the off-going range (ratio) remains
engaged even though the off-going clutch is commanded OFF.
Actions Taken When the DTC Sets
• When DTC P0777 occurs, the TCM will command previous range.
•
While the diagnostic response is active, the TCM ignores shift selectors inputs.
•
The CHECK TRANS light illuminates.
•
DTC is stored in TCM history.
•
The TCM inhibits TCC engagement.
•
The TCM freezes shift adapts (DNA).
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
• This DTC indicates the off-going clutch being controlled by PCS2 is not released or released too slowly.
Common causes include:
— Erratic turbine and output speed sensor readings.
— An obstruction in the C2 clutch exhaust circuit.
— A defective PCS2 solenoid.
— A stuck PCS2 regulator valve.
• PCS2 supplies hydraulic pressure to C3 clutch in reverse and to C2 clutch in fourth range through sixth range.
Review the Allison DOC™ For PC–Service Tool failure record data for previous or current range information
when the DTC was set to determine which clutch circuit is suspect.
•
PCS1 and PCS2 are “normally high” solenoids. PCS1 and PCS2 supply full hydraulic pressure when their coils
are de-energized, and no output pressure when receiving maximum current from the TCM.
6–168
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
•
If the condition is intermittent, connect Allison DOC™ For PC–Service Tool and observe the speed sensor
indicated by the code. If the signal is erratic, investigate and eliminate the following:
— Intermittent wiring connection
— Excessive vibration (driveline or engine torsionals)
— Irregular sensor gap (loose sensor, loose tone wheel, or damaged tone wheel).
Test Description
The numbers below refer to step numbers on the diagnostic table.
2. This step tests for proper transmission fluid level.
3. This step tests for active diagnostic codes.
4. This step tests ignition voltage.
5. This step tests speed sensor readings.
6. This step tests for C2 or C3 clutch pressure from PCS2.
7. This step tests for evidence of clutch failure.
8. This step tests for stuck or sticking valves and damaged valve body gaskets.
DTC P0777 Pressure Control Solenoid 2 Stuck On
Step
1
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
2
Perform the Fluid Check Procedure (refer to
appropriate mechanic’s tips).
Is the transmission fluid level correct?
1. Install the Allison DOC™ For PC–Service Tool.
2. Turn ON the ignition, leave engine OFF.
3. Record the failure records.
4. Clear the DTC.
5. Drive the vehicle. Attempt to duplicate same
operating conditions observed in failure records.
3
Value(s)
Yes
Go to Step 2
Go to Step 3
Go to Step 4
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Go to Fluid Check
Procedure (refer to
mechanic’s tips)
Go to
Diagnostic Aids
NOTE: This DTC indicates that the TCM has
detected that the off-going clutch did not release
(clutch tie-up) following a shift.
4
5
Did DTC P0777 return?
1. Install the Allison DOC™ For PC–Service Tool. 9–18V (12V TCM)
Go to Step 5
18–32V (24V TCM)
2. Start the engine.
3. Record the DTC failure record data.
4. Using the Allison DOC™ For PC–Service Tool,
measure ignition voltage.
Is the voltage within the specified value?
1. Start the engine and drive the vehicle under
Watch for erratic
Go to the
normal operating conditions.
Appropriate Speed
speed sensor
Sensor DTC
2. Using Allison DOC™ For PC–Service Tool,
signals
monitor turbine, engine, and output speed sensor
readings using the strip chart display.
Is speed sensor data erratic or are dropouts in signal
indicated?
Copyright © 2005 General Motors Corp.
Go to General
Troubleshooting
Section 8
Go to Step 6
6–169
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0777 Pressure Control Solenoid 2 Stuck On (cont’d)
Step
6
7
8
9
10
11
6–170
Action
1. Turn OFF the ignition.
2. Install 2000 kPa (300 psi) pressure gauges in
main and C2 and C3 pressure taps.
3. Start the engine.
4. Using Allison DOC™ For PC–Service Tool,
select the clutch test mode.
5. With brakes applied, select and attain the range
where the DTC occurred as indicated in the
failure records.
6. Read and record Main, C2, and C3 clutch
pressures.
Are the pressure readings within specified values in
Appendix B?
Remove the dipstick and inspect the transmission
fluid for clutch debris or burnt odor. If necessary,
drain a small amount of fluid for this inspection.
Are there signs of a clutch failure?
1. Consult the service manual and remove the
transmission hydraulic control module.
2. Inspect the control valve bodies for stuck or
sticking solenoid regulator valves and logic latch
valves.
3. Inspect the suction filter. Be sure screen is not
plugged.
4. Inspect for damaged gaskets and face seals.
Was a valve body problem found and repaired?
Replace PCS2.
Is the replacement complete?
Remove the main and lube filters and inspect for
clutch debris. It may also be necessary to remove the
control module and inspect the suction screen for
clutch debris.
If debris is found, remove the transmission for
overhaul or replacement (refer to the appropriate
service manual).
Is the replacement complete?
Value(s)
Refer to Main and
Clutch Pressure
specifications in
Appendix B
In order to verify your repair:
1. Clear the DTC.
2. Using Allison DOC™ For PC–Service Tool,
monitor engine, turbine, and output speed sensor
readings.
3. Drive the vehicle under normal operating
conditions.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 7
No
Go to Step 8
Go to Step 10
Go to
Diagnostic Aids
Go to Step 11
Go to Step 9
Go to Step 11
Go to Step 11
Begin the
diagnosis again.
Go to Step 1
System OK
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0796 Pressure Control Solenoid 3 Stuck Off
Refer to Hydraulic Schematic
Circuit Description
The Transmission Control Module (TCM) uses input from the turbine speed and the output speed sensors to detect
if a clutch is slipping. Pressure Control Solenoid 3 (PCS3) supplies hydraulic pressure to the C5 clutch in reverse,
neutral, and first; and to the C3 clutch in third and fifth. The TCM sets a DTC P0796 when it detects a slip
condition while PCS3 is supplying hydraulic pressure to the oncoming clutch.
Conditions for Running the DTC
•
Hydraulic system is pressurized.
•
Output speed greater than or equal to 125 rpm.
•
Turbine speed greater than or equal to 60 rpm.
•
Cold Mode operation not required.
Conditions for Setting the DTC
DTC P0796 sets when the TCM detects an incorrect oncoming ratio (range-to-range) for an accumulated number
of occurrences.
Actions Taken When the DTC Sets
•
When DTC P0796 occurs, the TCM will command previous range.
•
While the Diagnostic Response is active, the TCM will ignore shift selector inputs.
•
The CHECK TRANS light illuminates.
•
DTC is stored in TCM history.
•
The TCM inhibits TCC engagement.
•
The TCM freezes shift adapts (DNA).
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
•
This DTC indicates the oncoming clutch being controlled by PCS3 is not applied or applied too slowly.
Common causes include:
— Erratic turbine or output speed signals.
— A leak or obstruction in a specific clutch apply circuit.
— A defective solenoid.
— A stuck PCS3 regulator valve.
— A stuck C1 or C2 logic latch valve.
•
PCS3 supplies hydraulic pressure to C5 clutch in reverse, neutral and first range; and to C3 clutch in third and
fifth ranges. Review the Allison DOC™ For PC–Service Tool failure record data for previous or current range
information when the DTC was set to determine which clutch circuit is suspect.
Copyright © 2005 General Motors Corp.
6–171
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
•
If the condition is intermittent, connect Allison DOC™ For PC–Service Tool and observe the speed sensor
indicated by the code. If the signal is erratic, investigate and eliminate the following:
— Intermittent wiring connection
— Excessive vibration (driveline or engine torsionals)
— Irregular sensor gap (loose sensor, loose tone wheel, or damaged tone wheel).
Test Description
The numbers below refer to step numbers on the diagnostic table.
2. This step tests for proper transmission fluid level.
3. This step tests for active diagnostic codes.
4. This step tests ignition voltage.
5. This step tests speed sensor readings.
6. This step tests for C3 and C5 clutch pressure from PCS3.
7. This step tests for evidence of clutch failure.
8. This step tests for stuck or sticking valves and damaged valve body gaskets.
DTC P0796 Pressure Control Solenoid 3 Stuck Off
Step
1
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
2
Perform the Fluid Check Procedure (refer to
appropriate mechanic’s tips).
Is the transmission fluid level correct?
1. Install the Allison DOC™ For PC–Service Tool.
2. Turn ON the ignition, leave engine OFF.
3. Record the failure records.
4. Clear the DTC.
5. Drive the vehicle. Attempt to duplicate same
operating conditions observed in failure records.
3
Value(s)
Yes
Go to Step 2
Go to Step 3
Go to Step 4
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Go to Fluid Check
Procedure (refer to
mechanic’s tips)
Go to
Diagnostic Aids
NOTE: This DTC indicates that the TCM has
detected a slip condition and could not verify the
correct oncoming ratio following a shift.
4
5
6–172
Did DTC P0796 return?
1. Install the Allison DOC™ For PC–Service Tool. 9–18V (12V TCM)
Go to Step 5
18–32V (24V TCM)
2. Start the engine.
3. Record the DTC failure record data.
4. Using the Allison DOC™ For PC–Service Tool,
measure ignition voltage.
Is the voltage within the specified value?
1. Start the engine and drive the vehicle under
Watch for erratic
Go to the
normal operating conditions.
appropriate speed
speed sensor
sensor DTC
2. Using Allison DOC™ For PC–Service Tool,
signals
monitor turbine, engine, and output speed sensor
readings using the strip chart display.
Is speed sensor data erratic or are dropouts in signal
indicated?
Copyright © 2005 General Motors Corp.
Go to General
Troubleshooting
Section 8
Go to Step 6
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0796 Pressure Control Solenoid 3 Stuck Off (cont’d)
Step
6
7
8
9
10
11
Action
1. Turn the OFF the ignition.
2. Install 2000 kPa (300 psi) pressure gauges in
main, C3, and C5 pressure taps.
3. Start the engine.
4. Using Allison DOC™ For PC–Service Tool,
select the clutch test mode.
5. With brakes applied, select and attain the range
where the DTC occurred as indicated in the
failure records.
6. Read and record Main, C3, and C5 clutch
pressures.
Are the pressure readings within specified values in
Appendix B?
Remove the dipstick and inspect the transmission
fluid for clutch debris or burnt odor. If necessary,
drain a small amount of fluid for this inspection.
Are there signs of a clutch failure?
1. Consult the service manual and remove the
transmission hydraulic control module.
2. Inspect the control valve bodies for stuck or
sticking solenoid regulator valves and logic latch
valves.
3. Inspect the suction filter. Be sure screen is not
plugged.
4. Inspect for damaged gaskets and face seals.
Was a valve body problem found and repaired?
Replace PCS3.
Is the replacement complete?
Remove the main and lube filters and inspect for
clutch debris. It may also be necessary to remove the
control module and inspect the suction screen for
clutch debris.
If debris is found, remove the transmission for
overhaul or replacement (refer to the appropriate
service manual).
Is the replacement complete?
Value(s)
Refer to Main and
Clutch Pressure
specifications in
Appendix B
In order to verify your repair:
1. Clear the DTC.
2. Using Allison DOC™ For PC–Service Tool,
monitor engine, turbine, and output speed sensor
readings.
3. Drive the vehicle under normal operating
conditions.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 7
No
Go to Step 8
Go to Step 10
Go to
Diagnostic Aids
Go to Step 11
Go to Step 9
Go to Step 11
Go to Step 11
Begin the
diagnosis again.
Go to Step 1
System OK
6–173
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0797 Pressure Control Solenoid 3 Stuck On
Refer to Hydraulic Schematic
Circuit Description
The Transmission Control Module (TCM) uses information from the turbine and output speed sensors to detect if a
clutch is in a tie-up condition or if three clutches are applied. Pressure Control Solenoid 3 (PCS3) supplies
hydraulic pressure to the C5 clutch in reverse, neutral, and first; and to the C3 clutch in third and fifth ranges. The
TCM sets a DTC P0797 when it detects a tie-up condition while PCS3 is supplying hydraulic pressure to the offgoing clutch.
Conditions for Running the DTC
•
Hydraulic system is pressurized.
•
Output speed greater than or equal to 200 rpm.
•
Turbine speed greater than or equal to 200 rpm.
•
Cold Mode operation not required.
Conditions for Setting the DTC
DTC P0797 sets when the transmission is shifting from range to range and the off-going range (ratio) remains
engaged even though the off-going clutch is commanded OFF.
Actions Taken When the DTC Sets
•
When DTC P0797 occurs, the TCM will command previous range.
•
While Diagnostic Response is active, the TCM will ignore shift selector inputs.
•
The CHECK TRANS light illuminates.
•
DTC is stored in TCM history.
•
The TCM inhibits TCC engagement.
•
The TCM freezes shift adapts (DNA).
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
•
This DTC indicates the off-going clutch being controlled by PCS3 is not released or released too slowly.
Common causes include:
— Erratic turbine and output speed sensor readings.
— An obstruction in the C3 or C5 clutch exhaust circuit.
— A defective PCS3 solenoid.
— A stuck PCS3 regulator valve.
•
PCS3 supplies hydraulic pressure to C5 clutch in reverse, neutral and first range; and to C3 clutch in third and
fifth ranges. Review the Allison DOC™ For PC–Service Tool failure record data for previous or current range
information when the DTC was set to determine which clutch circuit is suspect.
6–174
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
•
If the condition is intermittent, connect Allison DOC™ For PC–Service Tool and observe the speed sensor
indicated by the code. If the signal is erratic, investigate and eliminate the following:
— Intermittent wiring connection
— Excessive vibration (driveline or engine torsionals)
— Irregular sensor gap (loose sensor, loose tone wheel, or damaged tone wheel).
Test Description
The numbers below refer to step numbers on the diagnostic table.
2. This step tests for proper transmission fluid level.
3. This step tests for active diagnostic codes.
4. This step tests ignition voltage.
5. This step tests speed sensor readings.
6. This step tests for C3 or C5 clutch pressure from PCS3.
7. This step tests for evidence of clutch failure.
8. This step tests for stuck or sticking valves and damaged valve body gaskets.
DTC P0797 Pressure Control Solenoid 3 Stuck On
Step
1
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
2
Perform the Fluid Check Procedure (refer to
appropriate mechanic’s tips).
Is the transmission fluid level correct?
1. Install the Allison DOC™ For PC–Service Tool.
2. Turn ON the ignition, leave engine OFF.
3. Record the failure records.
4. Clear the DTC.
5. Drive the vehicle. Attempt to duplicate same
operating conditions observed in failure records.
3
Value(s)
Yes
Go to Step 2
Go to Step 3
Go to Step 4
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Go at Fluid Check
Procedure (refer to
mechanic’s tips)
Go to
Diagnostic Aids
NOTE: This DTC indicates that the TCM has
detected that the off-going clutch did not release
(clutch tie-up) following a shift.
4
5
Did DTC P0797 return?
1. Install the Allison DOC™ For PC–Service Tool. 9–18V (12V TCM)
Go to Step 5
18–32V (24V TCM)
2. Start the engine.
3. Record the DTC failure record data.
4. Using the Allison DOC™ For PC–Service Tool,
measure ignition voltage.
Is the voltage within the specified value?
1. Start the engine and drive the vehicle under
Watch for erratic
Go to the
normal operating conditions.
appropriate speed
speed sensor
sensor DTC
2. Using Allison DOC™ For PC–Service Tool,
signals
monitor turbine, engine, and output speed sensor
readings using the strip chart display.
Is speed sensor data erratic or are dropouts in signal
indicated?
Copyright © 2005 General Motors Corp.
Go to General
Troubleshooting
Section 8
Go to Step 6
6–175
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0797 Pressure Control Solenoid 3 Stuck On (cont’d)
Step
6
7
8
9
10
11
6–176
Action
1. Turn OFF the ignition.
2. Install 2000 kPa (300 psi) pressure gauges in
main, C3, and C5 pressure taps.
3. Start the engine.
4. Using Allison DOC™ For PC–Service Tool,
select the Clutch Test Mode.
5. With brakes applied, select and attain the range
where the DTC occurred as indicated in the
failure records.
6. Read and record Main, C3 and C5 clutch
pressures.
Are the pressure readings within specified values in
Appendix B?
Remove the dipstick and inspect the transmission
fluid for clutch debris or burnt odor. If necessary,
drain a small amount of fluid for this inspection.
Are there signs of a clutch failure?
1. Consult the service manual and remove the
transmission hydraulic control module.
2. Inspect the control valve bodies for stuck or
sticking solenoid regulator valves and logic latch
valves.
3. Inspect the suction filter. Be sure screen is not
plugged.
4. Inspect for damaged gaskets and face seals.
Was a valve body problem found and repaired?
Replace PCS3.
Is the replacement complete?
Remove the main and lube filters and inspect for
clutch debris. It may also be necessary to remove the
control module and inspect the suction screen for
clutch debris.
If debris is found, remove the transmission for
overhaul or replacement (refer to the appropriate
service manual).
Is the replacement complete?
Value(s)
Refer to Main and
Clutch Pressure
specifications in
Appendix B
In order to verify your repair:
1. Clear the DTC.
2. Using Allison DOC™ For PC–Service Tool,
monitor engine, turbine, and output speed sensor
readings.
3. Drive the vehicle under normal operating
conditions.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 7
No
Go to Step 8
Go to Step 10
Go to
Diagnostic Aids
Go to Step 11
Go to Step 9
Go to Step 11
Go to Step 11
Begin the
diagnosis again.
Go to Step 1
System OK
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0842 Transmission Pressure Switch 1 Circuit Low
END VIEW OF
20-WAY CONNECTOR
END VIEW OF
80-WAY CONNECTOR
1
6
7
10
11
14
15
20
61
80
41
60
21
40
1
20
TO RETARDER
CONTROL DEVICES
RETARDER
REQUEST SENSOR
(RESISTANCE
MODULE)
A
PWM
THROTTLE
SOURCE
B
C
TCM
THROTTLE
POSITION
SENSOR (TPS)
OR
ELECTRONIC
BRAKING (EBS)
RTDR PRESSURE
SENSOR
WIRE 156
WIRE 112
C
WIRE 144
B
WIRE 158
A
RETARDER TEMP
ENGINE TEMP
TRANSMISSION
ANALOG RETURN
OIL LEVEL
HALL
A
C
EFFECT
B
SUMP TEMP
19
16
15
18
PS1
NC*
* NORMALLY
3
WIRE 175
WIRE 135
56
RETARDER REQUEST SIGNAL
12
5V SENSOR VOLTAGE
44
THROTTLE POSITION OR
RTDR PRESSURE SIGNAL
58
ANALOG RETURN
75
RETARDER TEMP
35
ENGINE WATER TEMP
16
OIL LEVEL SENSOR
54
SUMP TEMP
77
PS1 DIAGNOSTIC
PRESSURE SWITCH
WIRE 158
WIRE 112
WIRE 116
WIRE 154
WIRE 177
CLOSED
V09069.01.00
Copyright © 2005 General Motors Corp.
6–177
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0842 Transmission Pressure Switch 1 Circuit Low
Circuit Description
Diagnostic pressure switch 1 (PS1) is a normally closed switch. When the switch is depressurized, PS1 closes to
complete a circuit between wire 177 and analog return wire 158. The Transmission Control Module (TCM) detects
PS1 closed when it senses a ground on wire 177. When the switch is pressurized, PS1 opens and voltage on wire
177 goes high.
The TCM uses the signal from PS1 to confirm the following control valve functions:
•
When the C5 clutch is filled as in reverse, neutral, or first range—PS1 senses PCS2 solenoid regulator valve
position to verify proper C3 clutch control in these three ranges.
•
When the C5 clutch is exhausted as in second through sixth ranges—PS1 monitors C1 and C2 latch valve
position.
Conditions for Running the DTC
•
Hydraulic system pressurized
•
Initialization complete
•
Transmission sump temperature greater than –15°C (5°F)
Conditions for Setting the DTC
DTC P0842 sets if the TCM detects that PS1 is EXHAUSTED when it should be PRESSURIZED. Specifically, the
TCM will set a P0842 code if it senses that PS1 is EXHAUSTED during the following conditions:
•
Integrity Test
— The C5 clutch is filled and PCS2 solenoid is commanded ON, or
— The C5 clutch is exhausted and both latch valves are stroked.
•
Time Out Test
— After a change in latch valve states that ends up with both latch valves stroked.
Actions Taken When the DTC Sets
When DTC P0842 occurs:
•
The TCM will lock in range.
•
While the diagnostic response is active, the TCM ignores shift selector inputs.
•
The CHECK TRANS light illuminates.
•
DTC is stored in TCM history.
•
The TCM inhibits TCC engagement.
•
The TCM freezes shift adapts (DNA).
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the code from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
•
Unlike the WTEC II/III C3 pressure switch, the Allison 4th Generation Pressure Switch 1 (PS1) closes when
exhausted, and opens when pressurized.
6–178
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
•
DTC P0842 may be caused by:
— Low transmission fluid level.
— Defective PS1 pressure switch.
— Stuck C1 or C2 latch valves.
— Defective shift solenoid SS1.
— Stuck diagnostic valve.
— A short-to-ground in wire 177.
— Worn or damaged charging pump.
•
Compare transmission fluid level measurements when the engine is shutdown and when the engine is
operating. Fluid level should drop after starting the engine. If level does not change, the transmission charging
pump may have failed.
•
Inspect the wiring for poor electrical connections at the TCM. Look for the following conditions:
— A bent terminal
— A backed-out terminal
— A damage terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
•
When diagnosing for an intermittent short or open, massage the wiring harness while watching the test
equipment for a change It may be necessary to test for shorting-to-ground at individual wires within a harness
to isolate an intermittent condition (refer to Section 4, Wire Test Procedures).
•
You may have to drive the vehicle in order to experience a fault. The data obtained from failure records can be
useful in reproducing failure modes when the DTC was set.
Test Description
This DTC requires the use of the J 47275 TCM Breakout. The numbers below refer to step numbers on the
diagnostic table.
2. This step tests for proper transmission fluid level.
3. This step verifies failure conditions.
4. This step tests the entire PS1 circuit.
5. This step tests for internal short in TCM.
6. This step tests for wiring defects in OEM harness.
9. This step tests defective internal harness.
13. This step tests for active diagnostic code.
14. This step tests for low main pressure.
15. This step tests for proper function of SS1 solenoid.
16. This step test stuck valves in the hydraulic control module.
18. This step tests for the cause of low main pressure.
DTC P0842 Transmission Pressure Switch 1 Circuit Low
Step
1
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
Copyright © 2005 General Motors Corp.
Yes
Go to Step 2
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
6–179
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0842 Transmission Pressure Switch 1 Circuit Low (cont’d)
Step
2
3
4
5
6–180
Action
Perform the Fluid Check Procedure (refer to
appropriate mechanic’s tips).
NOTE: If transmission fluid was recently drained
and refilled, allow the engine to run for a few
minutes to prime the main pump and clutch apply
circuits.
Value(s)
Is the transmission fluid level correct?
1. Install Allison DOC™ For PC–Service Tool.
2. Turn ON the ignition, with the engine OFF.
3. Record failure records.
4. Clear the DTC.
5. Start vehicle and test drive. Attempt to duplicate
the same conditions observed in failure records
(range attained, transmission temperature, etc.).
Did DTC P0842 return?
1. Turn OFF the ignition.
2. Disconnect the transmission 20-way connector.
3. Turn ON the ignition, with the engine OFF.
4. Observe PS1 status on Allison DOC™ For PC–
Service Tool.
NOTE: Allison DOC™ For PC–Service Tool
should show PS1 switch status as PRESSURIZED
under these test conditions.
Does Allison DOC™ For PC–Service Tool show
PS1 EXHAUSTED?
1. Turn OFF the ignition.
2. Install a 2000 kPa (300 psi) pressure gauge in
main pressure tap.
3. Start the engine.
4. Read and record main pressure.
Is the pressure reading within specified value in
Appendix B?
Refer to Main and
Clutch Pressure
specifications in
Appendix B
Copyright © 2005 General Motors Corp.
Yes
Go to Step 3
No
Go to Fluid Check
Procedure (refer to
mechanic’s tips)
Go to Step 4
Go to
Diagnostic Aids
Go to Step 5
Go to Step 12
Go to Step 6
Go to Step 10
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0842 Transmission Pressure Switch 1 Circuit Low (cont’d)
Step
6
7
8
9
10
Action
WARNING: To help avoid injury or property
damage caused by sudden and unexpected
vehicle movement, do not start a stationary
stall test until you:
• Put the transmission in N (Neutral).
• Apply the parking brake and service brake.
• Chock the wheels and take any other steps
necessary to prevent the vehicle from
moving.
• Warn personnel to keep clear of the vehicle
and its path.
Value(s)
Refer to Main and
Clutch Pressure
specifications in
Appendix B
1. Turn OFF the ignition.
2. Install 2000 kPa (300 psi) gauges in C1 and C2
pressure taps.
3. Start the engine.
4. Using Allison DOC™ For PC–Service Tool,
select the clutch test mode.
5. With brakes applied, select D (Drive).
6. With the engine at idle speed, select and attain
fourth range.
Are both C1 and C2 pressure readings within
specified values in Appendix B?
1. Verify the ignition is in the OFF position.
2. Consult appropriate transmission service manual
and remove the control module from the
transmission.
3. Disconnect PS1.
4. Using a DVOM, test pin 3 in the internal wiring
harness for pin-to-pin shorts, and shorts-toground.
Were any pin-to-pin shorts or shorts-to-ground
found?
Replace the internal wiring harness.
Is the replacement complete?
Replace pressure switch PS1.
Is the replacement complete?
1. Verify the ignition is in the OFF position.
2. Consult appropriate transmission service manual
and remove the control module from the
transmission.
3. Inspect the solenoid and main valve bodies for
sticking or defective diagnostic valve, PCS1 and
PCS2 solenoid regulator valves, or C1 and C2
latch valves.
Was a defective valve found or repaired?
Copyright © 2005 General Motors Corp.
Yes
Got to Step 7
No
Go to Step 10
Go to Step 8
Go to Step 9
Go to Step 17
Go to Step 17
Go to Step 17
Go to Step 11
6–181
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0842 Transmission Pressure Switch 1 Circuit Low (cont’d)
Step
11
12
13
14
15
Action
Replace the solenoid that is controlling the
malfunctioning clutch (as indicated by pressure
readings obtained in step 6 above).
• C1 clutch – PCS1 solenoid
• C2 clutch – PCS2 solenoid
• Both C1 and C2 clutch – SS1 solenoid
Value(s)
Is the repair complete?
1. Turn OFF the ignition.
2. Install the J 47275 TCM Breakout at the TCM
80-way connector.
3. Disconnect the 16-pin bypass connector on
J 47275 TCM Breakout.
4. Turn ON the ignition.
5. Observe PS status on Allison DOC™ For PC–
Service Tool.
NOTE: Allison DOC™ For PC–Service Tool
should show PS1 switch status as PRESSURIZED
under these test conditions.
Does Allison DOC™ For PC–Service Tool show
PS1 PRESSURIZED?
1. Turn OFF the ignition.
2. Inspect the routing of the PS1 sense wire 177
between the TCM and the transmission 20-way
connector.
3. Disconnect the TCM from J 47275 TCM
Breakout. Leave the OEM-side connected.
4. Reconnect the 16-pin bypass connector on
J 47275 TCM Breakout.
5. Disconnect the transmission 20-way connector.
6. Using a DVOM at J 47275-1 TCM Overlay, test
for wire-to-wire shorts and shorts-to-ground at
pin 177 (PS1 signal).
Were short-to-ground or wire damage found?
NOTE: The vehicle OEM has responsibility for all
external wiring harness repairs. Harness repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Coordinate with the vehicle OEM to repair or
replace the vehicle wiring.
Is the repair complete?
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
Refer to TCM diagnostic procedure, Section 3–6.
Is Section 3–6 complete?
6–182
Copyright © 2005 General Motors Corp.
Yes
Go to Step 17
No
Go to Step 13
Go to Step 14
Go to Step 17
Go to Step 17
Go to
Diagnostic Aids
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0842 Transmission Pressure Switch 1 Circuit Low (cont’d)
Step
16
17
Action
Investigate the cause of low main pressure. Possible
causes include:
• Collapsed main filter
• Broken converter pump or PTO gear tangs
• Worn main charging pump.
Value(s)
Is the cause of low main pressure repaired?
In order to verify your repair:
1. Clear the DTC.
2. Use Allison DOC™ For PC–Service Tool to
monitor pressure switch PS1 status.
3. Drive the vehicle under conditions noted in
failure records.
Did the DTC P0842 return?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 17
No
Begin the
diagnosis again.
Go to Step 1
System OK
6–183
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0843 Transmission Pressure Switch 1 Circuit High
END VIEW OF
20-WAY CONNECTOR
END VIEW OF
80-WAY CONNECTOR
1
6
7
10
11
14
15
20
61
80
41
60
21
40
1
20
TO RETARDER
CONTROL DEVICES
RETARDER
REQUEST SENSOR
(RESISTANCE
MODULE)
A
PWM
THROTTLE
SOURCE
B
C
TCM
THROTTLE
POSITION
SENSOR (TPS)
OR
ELECTRONIC
BRAKING (EBS)
RTDR PRESSURE
SENSOR
WIRE 156
WIRE 112
C
WIRE 144
B
WIRE 158
A
RETARDER TEMP
ENGINE TEMP
TRANSMISSION
ANALOG RETURN
OIL LEVEL
HALL
A
C
EFFECT
B
SUMP TEMP
19
16
15
18
PS1
NC*
* NORMALLY
3
WIRE 175
WIRE 135
56
RETARDER REQUEST SIGNAL
12
5V SENSOR VOLTAGE
44
THROTTLE POSITION OR
RTDR PRESSURE SIGNAL
58
ANALOG RETURN
75
RETARDER TEMP
35
ENGINE WATER TEMP
16
OIL LEVEL SENSOR
54
SUMP TEMP
77
PS1 DIAGNOSTIC
PRESSURE SWITCH
WIRE 158
WIRE 112
WIRE 116
WIRE 154
WIRE 177
CLOSED
V09069.01.00
6–184
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0843 Transmission Pressure Switch 1 Circuit High
Circuit Description
The TCM uses diagnostic pressure switch Pressure Switch 1 (PS1) to confirm the following control valve function.
While C5 clutch is filled as in reverse, neutral, or first range, PS1 senses Pressure Control Switch 2 (PCS2)
solenoid regulator valve position to verify C3 clutch control in these three ranges. While C5 is exhausted as in
second through sixth ranges, PS1 monitors C1 and C2 latch valve positions.
PS1 is a normally closed switch. When the switch is depressurized, PS1 closes to complete a circuit between wire
177 and analog return wire 158. The TCM detects PS1 closed when it senses a ground on wire 177. When the
switch is pressurized, PS1 opens and voltage on wire 177 goes high.
Conditions for Running the DTC
• Hydraulic system pressurized
•
Initialization complete
•
Transmission sump temperature greater than –15ºC (5ºF)
Conditions for Setting the DTC
DTC P0843 sets if the TCM detects that PS1 is pressurized in the following situations:
•
•
Integrity Test
— The C5 clutch is exhausted or PCS2 solenoid is commanded OFF, and at least one C1 and C2 latch valve is destroked.
Time Out Test
— After a change in latch valve states that starts with both latch valves stroked and ends up with at least one
latch valve de-stroked.
Actions taken when the DTC Sets
When DTC P0843 occurs:
—
—
—
—
—
—
The TCM will lock in range.
While the diagnostic response is active, the TCM ignores shift selector inputs.
The CHECK TRANS light illuminates.
DTC is stored in TCM history.
The TCM inhibits torque converter clutch (TCC) engagement.
The TCM freezes shift adapts (DNA).
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
• Inspect the wiring for poor electrical connections at the TCM. Look for the following conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
Copyright © 2005 General Motors Corp.
6–185
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
•
When only a P0843 is set, look for an intermittent open in the pressure switch circuit.
•
When diagnosing for an intermittent short or open, massage the wiring harness while watching the test
equipment for a change. It may be necessary to test for shorting-to-ground at individual wires within a harness
to isolate an intermittent condition (refer to Section 4, Wire Test Procedures).
•
You may have to drive the vehicle in order to experience a fault. The data obtained from failure records can be
useful in reproducing failure modes when the DTC was set.
Test Description
This DTC requires the use of the J 47275 TCM Breakout and J 47279 Transmission Breakout. The numbers below
refer to step numbers on the diagnostic table.
2. This step tests for proper transmission fluid level.
3. This step verifies failure conditions.
4. This step tests the TCM for PS1 switch status.
5. This step tests for internal open in TCM.
6. This step tests for wiring defects (opens) in OEM harness.
9. This step tests for opens in the internal harness.
DTC P0843 Transmission Pressure Switch 1 Circuit High
Step
1
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
2
Perform the Fluid Check Procedure (refer to
appropriate mechanic’s tips).
Is the transmission fluid level correct?
1. Install the Allison DOC™ For PC–Service Tool.
2. Turn ON the ignition, with the engine OFF.
3. Record failure records.
4. Clear the DTC.
5. Start vehicle and test drive. Attempt to duplicate
the same conditions observed in failure records
(range attained, transmission temperature, etc.).
3
Value(s)
NOTE: This DTC indicates that an open circuit
condition may exist in the OEM harness, internal
transmission harness, or PS1 diagnostic pressure
switch.
Did DTC P0843 return?
6–186
Copyright © 2005 General Motors Corp.
Yes
Go to Step 2
Go to Step 3
Go to Step 4
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Go to Fluid Check
Procedure (refer to
mechanic’s tips)
Go to
Diagnostic Aids
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0843 Transmission Pressure Switch 1 Circuit High (cont’d)
Step
4
5
6
7
8
Action
1. Turn OFF the ignition.
2. Disconnect the transmission 20-way connector.
3. Connect the OEM-side of the 20-way connector
to the J 47279 Transmission Breakout. Leave the
transmission-side disconnected.
4. At J 47279-1 Transmission Overlay, install a
jumper between pin 3 and a known good ground.
5. Turn ON the ignition, with the engine OFF.
6. Observe PS1 status on Allison DOC™ For PC–
Service Tool.
Does Allison DOC™ For PC–Service Tool show
PS1 PRESSURIZED?
1. Turn OFF the ignition.
2. Install the J 47275 TCM Breakout at the TCM
80-way connector.
3. Disconnect the 16-pin bypass connector on
J 47275 TCM Breakout.
4. At J 47275-1 TCM Overlay, install a jumper
between pin 77 and ground (pin 9 or pin 69).
5. Turn ON the ignition. Leave the engine OFF.
Does Allison DOC™ For PC–Service Tool show
PS1 PRESSURIZED?
1. Turn OFF the ignition.
2. Inspect the routing of the PS1 sense wire 177
between the TCM and transmission 20-way
connector.
3. Disconnect the TCM from J 47275 TCM
Breakout. Leave the OEM-side connected.
4. Reconnect the 16-pin bypass connector on
J 47275 TCM Breakout.
5. Disconnect the transmission 20-way connector.
6. Test for opens on wire 177.
Were opens or wire damage found?
NOTE: The vehicle OEM has responsibility for all
external wiring harness repairs. Harness repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Value(s)
Coordinate with the vehicle OEM to repair or
replace the vehicle wiring.
Is the repair complete?
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
Yes
Go to Step 5
No
Go to Step 9
Go to Step 8
Go to Step 6
Go to Step 7
Go to
Diagnostic Aids
Go to Step 12
Go to Step 12
Refer to TCM diagnostic procedure, Section 3–6.
Is Section 3–6 complete?
Copyright © 2005 General Motors Corp.
6–187
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0843 Transmission Pressure Switch 1 Circuit High (cont’d)
Step
9
10
11
12
6–188
Action
1. Consult appropriate transmission service manual
and remove the control module from the
transmission.
2. Disconnect PS1.
3. Using a DVOM, test for continuity across
pressure switch PS1.
Is there continuity across pressure switch PS1?
Replace the internal wiring harness.
Is the replacement complete?
Replace the pressure switch PS1.
Is the replacement complete?
In order to verify your repair:
1. Clear the DTC.
2. Using Allison DOC™ For PC–Service Tool,
monitor pressure switch PS1 status.
3. Drive the vehicle under normal operating
conditions.
Did the DTC return?
Value(s)
Copyright © 2005 General Motors Corp.
Yes
Go to Step 10
No
Go to Step 11
Go to Step 12
Go to Step 12
Begin the
diagnosis again.
Go to Step 1
System OK
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0880 TCM Power Input Signal
END VIEW OF
80-WAY CONNECTOR
61
80
41
60
21
40
1
20
163
170
110
15a
10a
169
IGN
SWITCH
109
+
63
IGNITION
POWER
70
10
BATTERY
POWER
BATTERY
POWER
69
GND
9
GND
TCM
–
12V/24V
BATTERY
V09140.00.00
Circuit Description
The Transmission Control Module (TCM) requires a switched ignition voltage input and a direct battery voltage
input. This switched ignition voltage signal originates from the ignition switch or an ignition relay to supply
voltage to pin 63 in the 80-way connector at the TCM. Battery direct voltage is supplied to pins 10 and 70 at the
80-way connector.
Conditions for Running the DTC
This test is continuously enabled.
Conditions for Setting the DTC
DTC P0880 sets during the next ignition cycle if battery power is lost before the power down process is complete
and the engine is running.
Actions Taken When the DTC Sets
When DTC P0880 is active, the following conditions will occur:
•
The TCM does not illuminate the CHECK TRANS light.
•
DTC is stored in TCM history.
•
The TCM loses adaptive information for the drive cycle.
•
The TCM reverts to previous adaptive settings.
Copyright © 2005 General Motors Corp.
6–189
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0880 TCM Power Input Signal
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
•
DTC P0880 may set if battery disconnects are opened before switching OFF ignition.
•
You may have to drive the vehicle in order to experience a fault.
•
Inspect the wiring for poor electrical connections at the TCM. Look for the following conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
•
When diagnosing for an intermittent short or open, massage the wiring harness while watching the test
equipment for a change.
Test Description
This DTC requires the use of the J 47275 TCM Breakout. The numbers below refer to step numbers on the
diagnostic table.
2. This step tests for proper battery voltage.
3. This step tests for proper charging system operation.
4. This step tests for proper system voltage.
5. This step tests for proper ignition voltage.
DTC P0880 TCM Power Input Signal
Step
1
2
3
6–190
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
1. Install the Allison DOC™ For PC–Service Tool. 10.5V (12V TCM)
22V (24V TCM)
2. Turn the ignition to the RUN position with the
engine OFF.
3. Record the DTC failure records.
4. Using a digital multimeter (DVOM), measure and
record voltage at the battery terminals.
Is voltage greater than specified value?
Start the engine and warm to normal operating
temperature.
Is the Alternator/Check Engine lamp ON?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 2
Go to Step 3
Repair charging
system
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Resolve battery
problem.
Go to Step 7
Go to Step 4
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0880 TCM Power Input Signal (cont’d)
Step
4
5
6
7
Action
Value(s)
1. Increase engine speed to 1000–1500 rpm.
13–15V (12V TCM)
25–30V (24V TCM)
2. Using Allison DOC™ For PC–Service Tool,
monitor system voltage.
Is the voltage within the specified values?
1. Turn OFF the ignition.
0.5V
2. Disconnect the 80-way connector from the TCM
and install J 47275 TCM Breakout between the
OEM and TCM connectors.
3. Using a DVOM, measure voltage between 80-way
connector pins 9 and 10 with ignition OFF.
4. Turn ON the ignition, leave engine OFF.
5. Using a DVOM, measure voltage between 80-way
connector pins 9 and 63 with ignition ON.
6. Subtract the voltage reading obtained in Step 5
from the voltage reading obtained in Step 3.
Is the difference between Step 3 voltage and Step 5
voltage greater than the specified value?
NOTE: The vehicle OEM has responsibility for all
external wiring harness repairs. Harness repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Repair the vehicle wiring harness.
Is the repair complete?
In order to verify your repair:
1. Clear the DTC.
2. Start the engine and warm to normal operating
temperature.
3. Using Allison DOC™ For PC–Service Tool,
monitor system voltage. System voltage should
be 9–18V.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 5
No
Repair charging
system
Go to Step 6
Go to
Diagnostic Aids
Go to Step 7
Begin the
diagnosis again.
Go to Step 1
System OK
6–191
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0881 TCM Power Input Signal Performance
END VIEW OF
80-WAY CONNECTOR
61
80
41
60
21
40
1
20
163
170
110
15a
10a
169
IGN
SWITCH
109
+
63
IGNITION
POWER
70
10
BATTERY
POWER
BATTERY
POWER
69
GND
9
GND
TCM
–
12V/24V
BATTERY
V09140.00.00
Circuit Description
The Transmission Control Module (TCM) requires a switched ignition voltage input and a direct battery voltage
input. This switched ignition voltage signal originates from the ignition switch or an ignition relay to supply
voltage to pin 63 in the 80-way connector at the TCM. Battery voltage is supplied to pins 10 and 70 at the 80-way
connector.
Conditions for Running the DTC
Engine speed is greater than 500 rpm for at least 1.5 seconds.
Conditions for Setting the DTC
DTC P0881 sets under the following conditions:
•
The TCM detects direct battery voltage below 5.5V. When battery voltage drops below 5.5V for 10 samples, a
fault pending is reported. DTC P0881 is set if voltage remains below 5.5V for 20 samples.
•
The TCM detects a large variation in direct battery voltage. When battery voltage varies by 4.0V or more for
10 samples, a fault pending is reported. DTC P0881 is set if ignition or battery voltage varies by 4.0V or more
for 20 samples.
6–192
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0881 TCM Power Input Signal Performance
Actions Taken When the DTC Sets
When DTC P0881 is active, the following conditions will occur:
•
The CHECK TRANS light does not illuminate.
•
DTC is stored in TCM history.
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
•
You may have to drive the vehicle in order to experience a fault.
•
This DTC indicates a variation in direct battery voltage.
— Battery voltage problems may be due to loose or corroded battery cables, a bad connection at the battery
direct feed terminal (10 or 70), or an internal TCM failure due to a burnt trace.
— A vehicle charging system failure may cause this DTC under certain circumstances.
•
This code may indicate that an internal voltage problem has occurred inside the TCM. The use of a substitute
TCM would be a good way to diagnose this problem.
•
A defective vehicle battery may induce this DTC.
•
Inspect the wiring for poor electrical connections at the TCM. Look for the following conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
•
When diagnosing for an intermittent short or open, massage the wiring harness while watching the test
equipment for a change.
Test Description
This DTC requires the use of the J 47275 TCM Breakout. The numbers below refer to step numbers on the
diagnostic table.
2. This step tests for an active DTC.
3. This step tests for proper direct battery input voltage.
4. This step tests for shorts or open conditions at direct battery input circuit.
Copyright © 2005 General Motors Corp.
6–193
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0881 TCM Power Input Signal Performance
Step
1
2
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
1.
2.
3.
4.
5.
Value(s)
Install the Allison DOC™ For PC–Service Tool.
Turn ON the ignition, leave engine OFF.
Record the failure records.
Clear the DTC.
Drive the vehicle. Attempt to duplicate same
operating conditions observed in failure records.
Yes
Go to Step 2
Go to Step 3
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Go to
Diagnostic Aids
NOTE: This DTC indicates that a voltage variation
exists in the battery input circuit. This variation is
measured for min. and max. voltage values. This
DTC sets if the voltage variation is present for a predetermined number of samples.
3
4
Did DTC P0881 return?
1. Turn OFF the ignition.
2. Disconnect the 80-way connector at the TCM.
3. Install J 47275 TCM Breakout between the OEM
and TCM 80-way connectors.
4. Using a digital multimeter (DVOM), sequentially
measure voltage at 80-way connector pins 9 and
10, then between pins 69 and 70.
Is the voltage within the specified values?
NOTE: The vehicle OEM has responsibility for all
external wiring harness repairs. Harness repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
11.5–12.5V
Repair charging
system
Go to Step 4
Go to Step 5
Inspect battery direct circuits 110 and 170 for one of
the following conditions:
• Intermittent open or short at battery direct
power and ground circuits 109, 110, 169, and
170.
• Loose or corroded connections at battery or
connection points.
• Defective battery.
5
6–194
Was one of these conditions discovered and
repaired?
In order to verify your repair:
1. Clear the DTC.
2. Start the engine and warm to normal operating
temperature.
3. Using Allison DOC™ For PC–Service Tool,
monitor system voltage. System voltage should
be 9–18V.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Begin the
diagnosis again.
Go to Step 1
System OK
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0882 TCM Power Input Signal Low
END VIEW OF
80-WAY CONNECTOR
61
80
41
60
21
40
1
20
163
170
110
15a
10a
169
IGN
SWITCH
109
+
63
IGNITION
POWER
70
10
BATTERY
POWER
BATTERY
POWER
69
GND
9
GND
TCM
–
12V/24V
BATTERY
V09140.00.00
Circuit Description
The Transmission Control Module (TCM) receives power directly from the battery. Wires 110 and 170 supply
direct battery power to pins 10 and 70 respectively at the TCM.
Conditions for Running the DTC
Engine has been running for more than 10 seconds and engine speed is greater than 450 rpm.
Conditions for Setting the DTC
DTC P0882 sets under the following condition:
•
The TCM detects battery voltage below 8V at 0°C (32°F) for six times. The voltage threshold is temperature
dependent varying from 5V at –60°C (–75°F) to 9V at 20°C (68°F).
Copyright © 2005 General Motors Corp.
6–195
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0882 TCM Power Input Signal Low
Actions Taken When the DTC Sets
When DTC P0882 is active, the following conditions will occur:
•
The CHECK TRANS light illuminates.
•
DTC is stored in TCM history.
•
Hydraulic default (SOL OFF) is commanded. The shift selector position and hydraulic state of latch valves
determine the range attained.
•
TCM inhibits TCC engagement.
•
TCM freezes shift adapts (DNA).
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
•
A defective vehicle battery may allow this DTC to set. Test the vehicle battery to verify proper voltage and load
capacity.
•
A defective vehicle charging system may cause this DTC.
•
Intermittent faults may exist in vehicle components such as a poor connection at the battery posts. Such faults
would cause this DTC to set and not remain active.
•
Inspect the wiring for poor electrical connections at the TCM. Look for the following conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
•
When diagnosing for an intermittent short or open, massage the wiring harness while watching the test
equipment for a change.
Test Description
The numbers below refer to step numbers on the diagnostic table.
2. This step tests for proper battery voltage.
3. This step tests for an active DTC.
4. This step tests vehicle battery per OEM guidelines.
5. This step tests vehicle charging system per OEM guidelines.
6–196
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0882 TCM Power Input Signal Low
Step
1
2
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
1.
2.
3.
4.
5.
Value(s)
Install the Allison DOC™ For PC–Service Tool. 9–18V (12V TCM)
18–32V (24V TCM)
Turn ON the ignition, leave engine OFF.
Record the failure records.
Clear the DTC.
Observe the battery voltage value on Allison
DOC™ For PC–Service Tool.
Yes
Go to Step 2
Go to Step 4
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Go to Step 3
NOTE: This DTC sets when battery voltage drops
below a predetermined level that is temperature
dependent for a pre-determined number of
detections.
3
4
Is the battery voltage below specified value?
1. Start the vehicle, if possible.
2. If the DTC is not active, drive the vehicle.
Attempt to duplicate the same operating
conditions observed in the failure records.
Did the DTC return?
Test the vehicle battery per OEM instructions. This
should include a voltage test and a load test.
Does test indicate the battery is good?
5
Test the vehicle charging system per the OEM
recommended testing procedure.
Is the charging system operating properly?
6
In order to verify your repair:
1. Clear the DTC.
2. Start the engine and warm to normal operating
temperature.
Did the DTC return?
Refer to OEM for
correct battery
specifications
Refer to OEM for
correct charging
system
specifications
Copyright © 2005 General Motors Corp.
Go to Step 4
Go to
Diagnostic Aids
Go to Step 5
Replace vehicle
battery.
Go to Step 6
Go to
Diagnostic Aids
Repair the
charging system.
Go to Step 6
Begin the
diagnosis again.
Go to Step 1
System OK
6–197
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0883 TCM Power Input Signal High
END VIEW OF
80-WAY CONNECTOR
61
80
41
60
21
40
1
20
163
170
110
15a
10a
169
IGN
SWITCH
109
+
63
IGNITION
POWER
70
10
BATTERY
POWER
BATTERY
POWER
69
GND
9
GND
TCM
–
12V/24V
BATTERY
V09140.00.00
Circuit Description
The Transmission Control Module (TCM) receives power directly from the battery. Wires 110 and 170 supply
direct battery power to pins 10 and 70 respectively at the TCM.
Conditions for Running the DTC
Engine has been running for more than 10 seconds and engine speed is greater than 450 rpm.
Conditions for Setting the DTC
DTC P0883 sets under the following conditions:
•
12V TCM—The TCM detects an ignition voltage greater than or equal to 16V for 6 out of 10 samples.
•
24V TCM—The TCM detects an ignition voltage greater than or equal to 32V for 6 out of 10 samples.
6–198
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0883 TCM Power Input Signal High
Actions Taken When the DTC Sets
When DTC P0883 is active, the following conditions will occur:
•
The CHECK TRANS light does not illuminate.
•
DTC is stored in TCM history.
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
• A defective vehicle charging system that is overcharging may cause this DTC.
•
Intermittent faults may exist in vehicle components such as a poor connection at the battery posts. Such faults
would cause this DTC to set and not remain active.
•
Inspect the wiring for poor electrical connections at the TCM. Look for the following conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
When diagnosing for an intermittent short or open, massage the wiring harness while watching the test
equipment for a change.
•
•
DTC P0883 may set if an A41 or A42 TCM is installed in a 24V electrical system.
Test Description
The numbers below refer to step numbers on the diagnostic table.
2. This step tests for proper battery voltage.
3. This step tests for an active DTC.
4. This step tests vehicle charging system per OEM guidelines.
Copyright © 2005 General Motors Corp.
6–199
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0883 TCM Power Input Signal High
Step
1
2
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
1.
2.
3.
4.
5.
Install the Allison DOC™ For PC–Service Tool.
Turn ON the ignition, leave engine OFF.
Record the failure records.
Clear the DTC.
Observe the battery voltage value on Allison
DOC™ For PC–Service Tool.
Value(s)
Yes
Go to Step 2
Refer to
Conditions for
Setting DTC
Go to Step 4
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Go to Step 3
NOTE: This DTC sets when battery voltage is
detected at or above a predetermined level for a predetermined number of samples.
3
Is the battery voltage at or above specified value?
1. Start the vehicle, if possible.
2. If the DTC is not active, drive the vehicle.
Attempt to duplicate the same operating
conditions observed in the failure records.
Did the DTC return?
4
Test the vehicle charging system per the OEM
recommended testing procedure.
Is the charging system operating properly?
5
In order to verify your repair:
1. Clear the DTC.
2. Start the engine and warm to normal operating
temperature.
Did the DTC return?
6–200
Refer to OEM for
correct charging
system
specifications
Copyright © 2005 General Motors Corp.
Go to Step 4
Go to
Diagnostic Aids
Go to
Diagnostic Aids
Repair the
charging system.
Go to Step 5
Begin the
diagnosis again.
Go to Step 1
System OK
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0894 Transmission Component Slipping
Refer to First Range Hydraulic Schematic
Circuit Description
The Transmission Control Module (TCM) uses input from the turbine speed and the output speed sensors to verify
the transmission has attained first range when the operator selects D (Drive). If the TCM does not detect turbine
speed pull down following the shift into D (Drive), the TCM sets a Code P0894.
Conditions for Running the DTC
•
Hydraulic system is pressurized.
•
Hydraulic default condition not present.
•
Engine initialization or shutdown is not in progress.
Conditions for Setting the DTC
DTC P0894 sets when first range is selected and turbine speed remains above a calibrated value.
Actions Taken When the DTC Sets
When DTC P0894 is active, the following conditions will occur:
•
The TCM commands first range.
•
While diagnostic response is active, the TCM ignores shift selector inputs.
•
The CHECK TRANS light illuminates.
•
DTC is stored in TCM history.
•
The TCM inhibits torque converter clutch (TCC) engagement.
•
The TCM freezes shift adapts (DNA).
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the code from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
•
You may have to clear the DTC and drive the vehicle in order to experience a fault. Use the data obtained from
failure records to determine transmission range and/or certain vehicle operating variables such as temperature,
run time, etc. This data can be useful in reproducing failures mode where DTC was set.
•
DTC P0894 may be caused by the following:
— Improper transmission fluid level
— Stuck solenoid regulator valve
— Stuck C1 or C2 latch valve
— Defective pressure control or shift solenoid
— Mechanical problem with the C1 or C5 clutch
•
If this code is accompanied by a P0701, troubleshoot and correct the cause of the P0701 first.
Copyright © 2005 General Motors Corp.
6–201
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
Test Description
The numbers below refer to step numbers on the diagnostic table.
2. This step tests for presence of a code P0701.
3. This step tests for improper transmission fluid level.
4. This step tests for active diagnostic codes.
5. This step tests for low main pressure.
6. This step tests for proper clutch pressures in first range.
7. This step tests for signs of a clutch failure.
DTC P0894 Transmission Component Slipping
Step
1
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
2
If DTC P0701 is present, troubleshoot and resolve
before going to the next step.
Is a DTC P0701 present?
3
Perform the Fluid Check Procedure (refer to
mechanic’s tips).
Is the transmission fluid level correct?
4
1.
2.
3.
4.
5.
5
6
6–202
Install the Allison DOC™ For PC–Service Tool.
Start the engine.
Record DTC failure record data.
Clear the DTC.
Drive the vehicle under normal operating
conditions.
Did DTC P0894 return?
1. Turn OFF the ignition.
2. Install a 2000 kPa (300 psi) pressure gauge in the
main pressure tap.
3. Start the engine.
4. Read and record main pressure.
Is the pressure reading within the specified value in
Appendix B?
1. Turn OFF the ignition.
2. Install 2000 kPa (300 psi) pressure gauges in
main, C1 and C5 pressure taps.
3. Start the engine.
4. Select Drive and shift the transmission into first
range.
5. Read and record Main, C1, and C5 clutch
pressures.
Are the pressure readings within specified values in
Appendix B?
Value(s)
Yes
Go to Step 2
Go to DTC P0701
and resolve
before proceeding
to Step 3
Go to Step 4
Go to Step 5
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Go to Step 3
Go to Fluid Check
Procedure
(refer to
mechanic’s tips)
Go to
Diagnostic Aids
See Main and
Clutch Pressure
specifications in
Appendix B
Go to Step 6
Go to Step 10
See Main and
Clutch Pressure
specifications in
Appendix B
Go to Step 7
Go to Step 8
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0894 Transmission Component Slipping
Step
7
8
9
10
11
Action
Remove the dipstick and inspect the transmission
fluid for clutch debris or burnt odor. If necessary,
drain a small amount of fluid for this inspection.
Are there signs of a clutch failure?
1. Consult the appropriate service manual and
remove the transmission hydraulic control
module.
2. Inspect the control valve bodies for stuck or
sticking solenoid regulator valves and logic latch
valves.
3. Inspect the suction filter. Be sure screen is not
plugged.
4. Inspect for damaged gaskets and face seals.
Was a valve body problem found and repaired?
Using pressure readings obtained in Step 6 above,
replace the affected solenoid.
• Incorrect C1 pressure—PCS1
• Incorrect C5 pressure—PCS3
Value(s)
Is the replacement complete?
Investigate the cause of low main pressure. Possible
causes include:
• Collapsed main filter
• Broken converter pump or PTO gear tangs
• Worn main charging pump
Is the cause of low main pressure repaired?
Remove the main and lube filters and inspect for
clutch debris. It may also be necessary to remove the
control module and inspect the suction screen for
clutch debris.
If debris is found, remove the transmission for
overhaul or replacement (refer to the appropriate
service manual).
Is the replacement complete?
In order to verify your repair:
1. Clear the DTC.
2. Drive the vehicle under normal operating
conditions.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 11
No
Go to
Diagnostic Aids
Go to Step 12
Go to Step 9
Go to Step 12
Go to Step 12
Go to Step 12
Begin the diagnosis
again.
Go to Step 1
System OK
6–203
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0960 Pressure Control Solenoid Main Mod Control Circuit Open
END VIEW OF
80-WAY CONNECTOR
END VIEW OF
20-WAY CONNECTOR
1
6
7
10
11
14
15
20
61
80
41
60
21
40
1
20
TRANSMISSION
TRANSID
TCM
20
HSD1
PCS4
PCS6
MAIN MOD
1
2
7
8
WIRE 176
WIRE 111
WIRE 155
WIRE 178
WIRE 174
76
11
TRANSID
HSD1
ANALOG
INTERFACE
55
78
V BATTERY
74
V09066.00.00
Circuit Description
Pressure control solenoid Main Mod solenoid is a normally closed (N/C) solenoid used to modulate the
transmission main pressure schedule. The TCM commands the solenoid ON when specific transmission and engine
conditions are met. When the Main Mod solenoid is commanded ON, pressure is routed to the main regulator valve
lowering the main pressure schedule.
The TCM sends control current to the Main Mod solenoid from High Side Driver 1 (HSD1) via wire 111. HSD1 is
continuously ON unless the TCM detects a fault condition. The TCM regulates the amount of current to the Main
Mod solenoid by switching the Main Mod solenoid’s Low Side Driver ON and OFF. Wire 174 completes the circuit
between the Main Mod solenoid and its Low Side Driver (LSD). DTC P0960 indicates that the TCM has detected
an open condition in the Main Mod solenoid electrical circuit. The open condition may exist in the high side
(wire 111) or low side (wire 174).
Conditions for Running the DTC
•
The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater
than 9V and less than 32V (24V TCM).
•
TCM initialization is in process or engine speed is greater than 200 rpm and less than 7500 rpm for 5 seconds.
6–204
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0960 Pressure Control Solenoid Main Mod Control Circuit Open
Conditions for Setting the DTC
DTC P0960 is set when the TCM detects an open circuit on the Main Mod solenoid return circuit for more than
2 seconds.
Actions Taken When the DTC Sets
When DTC P0960 is active, the following conditions will occur:
•
The CHECK TRANS light illuminates.
•
DTC is stored in TCM history.
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
•
DTC P0960 indicates an open in the electrical circuit for the Main Mod solenoid. In addition to the Main Mod
solenoid, HSD1 also supplies power to Pressure Control Solenoids 4 (PCS4) and PCS6. If DTC P0960 is
accompanied by DTC P2718 (PCS4 open circuit) and/or DTC P2812 (PCS6 open circuit), the open is most
likely in the high side of the circuit.
•
You may have to drive the vehicle in order to experience a fault. Use the data obtained from failure records to
determine transmission range and/or certain vehicle operating variables such as temperature, run time etc. This
data can be useful in reproducing the failure mode when DTC was set.
•
Inspect the wiring for poor electrical connections at the TCM and transmission connector. Look for the
following conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
Inspect OEM wiring harness routing, look for possible contact points where chafing could occur leading to an
open or short circuit condition. Moving parts on the vehicle could be contacting the harness; this includes
parking brake drum, suspension components, etc.
When diagnosing for an intermittent short or open, massage the wiring harness while watching the test
equipment for a change.
•
•
Test Description
This DTC requires the use of the J 47275 TCM Breakout and J 47279 Transmission Breakout. The numbers below
refer to step numbers on the diagnostic table.
2. This step tests for the proper ignition voltage.
3. This step tests for an active DTC.
4. This step tests the OEM harness for an excessive voltage drop caused by an open condition in either wire
111 or wire 174 of the OEM chassis harness.
6. This step tests for an open condition in the transmission internal harness.
7. This step tests for the proper the Main Mod solenoid resistance.
Copyright © 2005 General Motors Corp.
6–205
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0960 Pressure Control Solenoid Main Mod Control Circuit Open
Step
1
2
3
6–206
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
1. Install the Allison DOC™ For PC–Service Tool. 9–18V (12V TCM)
2. Start the engine.
18–32V (24V TCM)
3. Record the failure records.
4. Monitor ignition voltage.
Is the voltage within the specified values?
1. Clear the DTC.
2. Start the engine and test drive the vehicle.
3. Attempt to duplicate the same conditions
observed in the failure records (range attained,
temperature, etc.).
NOTE: This DTC is intended to detect an open
condition in the Main Mod solenoid electrical
circuit.
Did DTC P0960 return?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 2
Go to Step 3
Go to Step 4
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Resolve voltage
problem.
Go to Step 11
Go to
Diagnostic Aids
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0960 Pressure Control Solenoid Main Mod Control Circuit Open (cont’d)
Step
4
5
6
Action
NOTE: Review Section 4—Wire Test Procedures
before performing steps.
1. Turn OFF the ignition.
2. Install J 47275 TCM Breakout between the OEM
and TCM 80-way connectors.
3. Install J 47279 Transmission Breakout between
the OEM and transmission 20-way connectors.
4. Turn ON the ignition, leave engine OFF.
5. Using Allison DOC™ For PC–Service Tool, enter
Solenoid Test mode and command the Main Mod
solenoid ON.
6. Determine the voltage drop in the high side of the
Main Mod solenoid circuit as follows:
• At J 47275-1 TCM Overlay, measure voltage
between pin 11 and an isolated ground.
• At J 47279-1 Transmission Overlay, measure
voltage between pin 1 and isolated ground.
• Subtract the two voltage measurements to
obtain the voltage drop in the circuit.
7. Determine the voltage drop in the low side of the
Main Mod solenoid circuit as follows:
• At J 47275-1 TCM Overlay, measure voltage
between pin 74 and an isolated ground.
• At J 47279 Transmission Breakout, measure
voltage between pin 8 and ground.
• Subtract the two voltage measurements to
obtain the voltage drop in the circuit.
NOTE: A voltage drop of more than 0.5V across
either circuit indicates an excessive voltage loss in
the OEM harness.
Did either high-side or low-side voltage drop exceed
0.5VDC?
NOTE: The vehicle OEM has responsibility for all
external wiring harness repairs. Harness repairs
performed by Allison Transmission distributors
and dealers are not covered by Allison
Transmission warranty.
Coordinate with the vehicle OEM to repair or
replace the vehicle wiring.
Is the repair complete?
1. Turn OFF the ignition.
2. Disconnect the OEM 20-way connector from
J 47279 Transmission Breakout. Leave the
transmission 20-way connector connected to the
breakout.
3. Using a digital multimeter (DVOM), measure the
resistance between pin 1 and pin 8 of the
transmission 20-way connector.
Is the resistance within the specified value?
Value(s)
Yes
Go to Step 5
No
Go to Step 6
Go to Step 11
Refer to Solenoid
Resistance Chart
(Appendix K)
Copyright © 2005 General Motors Corp.
Go to Step 10
Go to Step 7
6–207
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0960 Pressure Control Solenoid Main Mod Control Circuit Open (cont’d)
Step
7
8
9
10
11
6–208
Action
1. Remove the hydraulic control module assembly.
2. Disconnect the Main Mod solenoid from the
internal wiring harness.
3. Using a DVOM, measure the Main Mod solenoid
resistance at pins A and B.
Is resistance within the specified values?
Replace the internal wiring harness.
Is the replacement complete?
Replace the Main Mod solenoid.
Is the replacement complete?
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
Value(s)
Refer to Solenoid
Resistance Chart
(Appendix K)
Refer to TCM diagnostic procedure, Section 3–6.
Is Section 3–6 complete?
In order to verify your repair:
1. Clear the DTC.
2. Drive the vehicle under normal operating
conditions.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 8
No
Go to Step 9
Go to Step 11
Go to Step 11
Go to Step 11
Begin the
diagnosis again.
Go to Step 1
System OK
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0962 Pressure Control Solenoid Main Mod Control Circuit Low
END VIEW OF
80-WAY CONNECTOR
END VIEW OF
20-WAY CONNECTOR
1
6
7
10
11
14
15
20
61
80
41
60
21
40
1
20
TRANSMISSION
TRANSID
HSD1
PCS4
PCS6
MAIN MOD
TCM
20
1
2
7
8
WIRE 176
WIRE 111
WIRE 155
WIRE 178
WIRE 174
76
11
TRANSID
HSD1
ANALOG
INTERFACE
55
78
V BATTERY
74
V09066.00.00
Circuit Description
Main Mod solenoid is a normally closed (N/C) solenoid used to modulate the transmission main pressure schedule.
The TCM commands the solenoid ON when specific transmission and engine conditions are met. When the Main
Mod solenoid is commanded ON, pressure is routed to the main regulator valve lowering the main pressure
schedule.
The TCM sends control current to the Main Mod solenoid from High Side Driver 1 (HSD1) via wire 111. HSD1 is
continuously ON unless the TCM detects a fault condition. The TCM regulates the amount of current to the Main
Mod solenoid by switching the Main Mod solenoid’s Low Side Driver (LSD) ON and OFF. Wire 174 completes the
circuit between the Main Mod solenoid and its LSD. DTC P0962 indicates that the TCM has detected a short-toground condition in the low side of the Main Mod solenoid electrical circuit.
Conditions for Running the DTC
•
The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater
than 9V and less than 32V (24V TCM).
•
TCM initialization is in process or engine speed is greater than 200 rpm and less than 7500 rpm for 5 seconds.
Conditions for Setting the DTC
DTC P0962 is set when the TCM detects a short-to-ground in the Main Mod solenoid return circuit for more than
2 seconds.
Copyright © 2005 General Motors Corp.
6–209
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0962 Pressure Control Solenoid Main Mod Control Circuit Low
Actions Taken When the DTC Sets
When DTC P0962 is active, the following conditions will occur:
•
The CHECK TRANS light illuminates.
•
DTC is stored in TCM history.
•
Hydraulic default (SOL OFF) is commanded. The shift selector position and hydraulic state of latch valves
determine the range attained.
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
•
DTC P0962 indicates a short-to-ground in the electrical circuit for the Main Mod solenoid.
•
You may have to drive the vehicle in order to experience a fault. Use the data obtained from failure records to
determine transmission range and/or certain vehicle operating variables such as temperature, run time etc. This
data can be useful in reproducing the failure mode when DTC was set.
•
Inspect the wiring for poor electrical connections at the TCM and transmission connector. Look for the
following conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
•
Inspect OEM wiring harness routing, look for possible contact points where chafing could occur leading to an
open or short circuit condition. Moving parts on the vehicle could be contacting the harness; this includes
parking brake drum, suspension components, etc.
•
When diagnosing for an intermittent short or open, massage the wiring harness while watching the test
equipment for a change.
•
Advanced Troubleshooting (requires a frequency-capable digital multimeter, if available)—measure solenoid
LSD functionality as follows:
1. Install TCM breakout harness adapter J 47275 between the 80-way connectors of the TCM and OEM
harness.
2. Set up a frequency-capable digital multimeter, e.g. Fluke 87, to monitor frequency by selecting the
VOLTS-DC scale and depressing the HERTZ button once.
3. Connect the RED test lead to the solenoid low side pin at TCM breakout harness adapter J 47275. Connect the BLACK test lead to the isolated ground pin.
4. Use Allison DOC™ For PC–Service Tool solenoid test function to command the solenoid ON and OFF.
5. Frequency should read in the KILOHERTZ range when the driver is commanded ON. Frequency should
read 0 hertz when the driver is commanded OFF.
6–210
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
Test Description
This DTC requires the use of the J 47275 TCM Breakout. The numbers below refer to step numbers on the
diagnostic table.
2. This step tests for the proper ignition voltage.
3. This step tests for an active DTC.
4. This step tests for wire-to-wire shorts or a short-to-ground condition in wire 174.
6. This step tests for wire-to-wire shorts or a short-to-ground in the internal transmission harness.
DTC P0962 Pressure Control Solenoid Main Mod Control Circuit Low
Step
1
2
3
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
1. Install the Allison DOC™ For PC–Service Tool. 9–18V (12V TCM)
18–32V (24V TCM)
2. Start the engine.
3. Record the failure records.
4. Monitor ignition voltage.
Is the voltage within the specified values?
1. Clear the DTC.
2. Start the engine and test drive the vehicle.
3. Attempt to duplicate the same conditions
observed in the failure records (range attained,
temperature, etc.).
Yes
Go to Step 2
Go to Step 3
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Resolve voltage
problem.
Go to Step 11
Go to Step 4
Go to
Diagnostic Aids
Go to Step 5
Go to Step 6
NOTE: This DTC is intended to detect a short-toground condition in the Main Mod solenoid
electrical circuit.
4
Did DTC P0962 return?
NOTE: Review Section 4—Wire Test Procedures
before performing steps.
1. Turn OFF the ignition.
2. Disconnect the TCM 80-way connectors.
3. Install the OEM-side 80-way connector to the
J 47275 TCM Breakout. Leave the TCM
disconnected.
4. Disconnect the transmission 20-way connector.
5. Inspect the routing of wire 174 in the chassis
harness between the TCM and transmission
connector.
6. At J 47275-1 TCM Overlay, test for wire-to-wire
shorts between pin 74 and all other pins in the
80-way connector, and shorts-to-ground between
pin 74 and chassis ground.
Were any wire-to-wire shorts or shorts-to-ground
wiring defects found?
Copyright © 2005 General Motors Corp.
6–211
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0962 Pressure Control Solenoid Main Mod Control Circuit Low (cont’d)
Step
5
6
Action
NOTE: The vehicle OEM has responsibility for all
external wiring harness repairs. Harness repairs
performed by Allison Transmission distributors
and dealers are not covered by Allison
Transmission warranty.
Value(s)
Coordinate with the vehicle OEM to repair or
replace the vehicle wiring.
Is the repair complete?
1. Turn OFF the ignition.
2. Install J 47279 Transmission Breakout to the
transmission 20-way connector. Leave the OEM
harness disconnected.
3. Using DVOM, test for wire-to-wire shorts
between pin 8 and all other pins in the 20-way
connector, and shorts-to-ground between pin 8
and chassis ground.
Yes
Go to Step 11
No
Go to Step 7
Go to Step 10
Go to Step 8
Go to Step 9
NOTE: The resistance value between pins 8 and 1,
and between pins 8 and 20 will read normal
solenoid resistance. The resistance value between
pins 8 and 2, and between 8 and 7 (7-speed models)
will be twice normal solenoid resistance.
7
8
9
10
11
6–212
Were any wire-to-wire shorts or shorts-to-ground
found?
1. Remove the hydraulic control module assembly.
2. Inspect the internal harness for wire-to-wire
shorts or shorts-to-ground.
Were any wire-to-wire shorts or shorts-to-ground
found?
Replace the internal wiring harness.
Is the replacement complete?
Replace the Main Mod solenoid.
Is the replacement complete?
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
Refer to TCM diagnostic procedure, Section 3–6.
Is Section 3–6 complete?
In order to verify your repair:
1. Clear the DTC.
2. Drive the vehicle under normal operating
conditions.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Go to Step 11
Go to Step 11
Go to Step 11
Begin the
diagnosis again.
Go to Step 1
System OK
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0963 Pressure Control Solenoid Main Mod Control Circuit High
END VIEW OF
80-WAY CONNECTOR
END VIEW OF
20-WAY CONNECTOR
1
6
7
10
11
14
15
20
61
80
41
60
21
40
1
20
TRANSMISSION
TRANSID
HSD1
PCS4
PCS6
MAIN MOD
TCM
20
1
2
7
8
WIRE 176
WIRE 111
WIRE 155
WIRE 178
WIRE 174
76
11
TRANSID
HSD1
ANALOG
INTERFACE
55
78
V BATTERY
74
V09066.00.00
Circuit Description
Main Modulation Solenoid (Main Mod) is a normally closed (N/C) solenoid used to modulate the transmission
main pressure schedule. The TCM commands the solenoid ON when specific transmission and engine conditions
are met. When the Main Mod solenoid is commanded ON, pressure is routed to the main regulator valve lowering
the main pressure schedule.
The TCM sends control current to the Main Mod solenoid from High Side Driver 1 (HSD1) via wire 111. HSD1 is
continuously ON unless the TCM detects a fault condition. The TCM regulates the amount of current to the Main
Mod solenoid by switching the Main Mod solenoid’s Low Side Driver (LSD) ON and OFF. Wire 174 completes the
circuit between the Main Mod solenoid and its LSD. DTC P0963 indicates that the TCM has detected a short-tobattery condition in the low side of the Main Mod solenoid’s electrical circuit.
Conditions for Running the DTC
•
The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater
than 9V and less than 32V (24V TCM).
•
TCM initialization is in process or engine speed is greater than 200 rpm and less than 7500 rpm for 5 seconds.
Conditions for Setting the DTC
DTC P0963 is set when the TCM detects a short-to-battery in the Main Mod solenoid return circuit for more than
2 seconds.
Copyright © 2005 General Motors Corp.
6–213
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0963 Pressure Control Solenoid Main Mod Control Circuit High
Actions Taken When the DTC Sets
When DTC P0963 is active, the following conditions will occur:
•
The CHECK TRANS light illuminates.
•
DTC is stored in TCM history.
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
•
DTC P0963 indicates a short-to-battery in the electrical circuit for the Main Mod solenoid.
•
You may have to drive the vehicle in order to experience a fault. Use the data obtained from failure records to
determine transmission range and/or certain vehicle operating variables such as temperature, run time etc. This
data can be useful in reproducing the failure mode when DTC was set.
•
Inspect the wiring for poor electrical connections at the TCM and transmission connector. Look for the
following conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
•
Inspect OEM wiring harness routing, look for possible contact points where chafing could occur leading to an
open or short circuit condition. Moving parts on the vehicle could be contacting the harness; this includes
parking brake drum, suspension components, etc.
•
When diagnosing for an intermittent short or open, massage the wiring harness while watching the test
equipment for a change.
•
Advanced Troubleshooting (requires a frequency-capable digital multimeter, if available)—measure solenoid
LSD functionality as follows:
1. Install TCM breakout harness adapter J 47275 between the 80-way connectors of the TCM and OEM
harness.
2. Set up a frequency-capable digital multimeter, e.g. Fluke 87, to monitor frequency by selecting the
VOLTS-DC scale and depressing the HERTZ button once.
3. Connect the RED test lead to the solenoid low side pin at TCM breakout harness adapter J 47275. Connect the BLACK test lead to the isolated ground pin.
4. Use Allison DOC™ For PC–Service Tool solenoid test function to command the solenoid ON and OFF.
5. Frequency should read in the KILOHERTZ range when the driver is commanded ON. Frequency should
read 0 hertz when the driver is commanded OFF.
6–214
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
Test Description
This DTC requires the use of the J 47275 TCM Breakout and J 47279 Transmission Breakout. The numbers below
refer to step numbers on the diagnostic table.
2.
3.
4.
6.
This step tests for the proper ignition voltage.
This step tests for an active DTC.
This step tests for wire-to-wire shorts between wire 174 and other wires in the OEM chassis harness.
This step tests for the wire-to-wire shorts in the transmission internal harness.
DTC P0963 Pressure Control Solenoid Main Mod Control Circuit High
Step
1
2
3
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
1. Install the Allison DOC™ For PC–Service Tool. 9–18V (12V TCM)
18–32V (24V TCM)
2. Start the engine.
3. Record the failure records.
4. Monitor ignition voltage.
Is the voltage within the specified values?
1. Clear the DTC.
2. Start the engine and test drive the vehicle.
3. Attempt to duplicate the same conditions
observed in the failure records (range attained,
temperature, etc.).
Yes
Go to Step 2
Go to Step 3
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Resolve voltage
problem.
Go to Step 11
Go to Step 4
Go to
Diagnostic Aids
Go to Step 5
Go to Step 6
NOTE: This DTC is intended to detect a short-tobattery condition in the Main Mod solenoid
electrical circuit.
4
Did DTC P0963 return?
NOTE: Review Section 4—Wire Test Procedures
before performing steps.
1. Turn OFF the ignition.
2. Disconnect the 80-way connector.
3. Install the OEM-side of the 80-way connector to
the J 47275 TCM Breakout. Leave the TCM
disconnected.
4. Disconnect the transmission 20-way connector.
5. Inspect the routing of wires 111 and 174 in the
chassis harness between the TCM and the
transmission connector.
6. At J 47275-1 TCM Overlay, test for wire-to-wire
shorts between pin 74 and all other pins in the
80-way connector, and shorts-to-ground between
pin 74 and chassis ground.
Were any wire-to-wire shorts found?
Copyright © 2005 General Motors Corp.
6–215
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0963 Pressure Control Solenoid Main Mod Control Circuit High (cont’d)
Step
5
6
Action
NOTE: The vehicle OEM has responsibility for all
external wiring harness repairs. Harness repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Value(s)
Coordinate with the vehicle OEM to repair or
replace the vehicle wiring.
Is the repair complete?
1. Turn OFF the ignition.
2. Install J 47279 Transmission Breakout to the
transmission 20-way connector. Leave the OEM
harness disconnected.
3. Using a DVOM, test for wire-to-wire shorts
between pin 8 and all other pins in the 20-way
connector.
Yes
Go to Step 11
No
Go to Step 7
Go to Step 10
Go to Step 8
Go to Step 9
NOTE: The resistance value between pins 8 and 1,
and between pins 8 and 20 will read normal
solenoid resistance. The resistance value between
pins 8 and 2, and between 8 and 7 (7-speed models)
will be twice normal solenoid resistance.
7
8
9
10
11
6–216
Were any wire-to-wire shorts found?
1. Remove the hydraulic control module assembly.
2. Inspect the internal harness for wire-to-wire
shorts.
Were any wire-to-wire shorts found?
Repair or replace the internal wiring harness.
Is the repair complete?
Replace the Main Mod solenoid.
Is the replacement complete?
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
Refer to TCM diagnostic procedure, Section 3–6.
Is Section 3–6 complete?
In order to verify your repair:
1. Clear the DTC.
2. Drive the vehicle under normal operating
conditions.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Go to Step 11
Go to Step 11
Go to Step 11
Begin the
diagnosis again.
Go to Step 1
System OK
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0964 Pressure Control Solenoid 2 (PCS2) Control Circuit Open
END VIEW OF
80-WAY CONNECTOR
END VIEW OF
20-WAY CONNECTOR
1
6
7
10
11
14
15
20
61
80
41
60
21
40
1
20
TRANSMISSION
HSD2
PCS1
PCS2
PCS3
SS1
TCM
6
4
5
9
10
WIRE 171
WIRE 136
WIRE 152
WIRE 133
WIRE 151
71
HSD2
V BATTERY
36
52
33
51
V09067.00.00
Circuit Description
Pressure Control Solenoid 2 (PCS2) is a normally open (N/O) solenoid used to apply the C2 clutch in fourth
through sixth range, and the C3 clutch in Reverse. The TCM commands the solenoid OFF to produce hydraulic
pressure in the clutch apply circuit. When PCS2 is commanded ON, the C2 clutch is released.
The TCM sends control current to PCS2 from High Side Driver 2 (HSD2) via wire 171. HSD2 is continuously ON
unless the TCM detects a fault condition. The TCM regulates the amount of current to PCS2 by switching PCS2
Low Side Driver (LSD) ON and OFF. Wire 152 completes the circuit between PCS2 and its LSD. DTC P0964
indicates that the TCM has detected an open condition in PCS2 electrical circuit. The open condition may exist in
the high side (wire 171) or low side (wire 152).
Conditions for Running the DTC
•
The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater
than 9V and less than 32V (24V TCM).
•
TCM initialization is in process or engine speed is greater than 200 rpm and less than 7500 rpm for 5 seconds.
Conditions for Setting the DTC
DTC P0964 is set when the TCM detects an open circuit on the PCS2 return circuit for more than 2 seconds.
Copyright © 2005 General Motors Corp.
6–217
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0964 Pressure Control Solenoid 2 (PCS2) Control Circuit Open
Actions Taken When the DTC Sets
When DTC P0964 is active, the following conditions will occur:
•
The CHECK TRANS light illuminates.
•
DTC is stored in TCM history.
•
Hydraulic default (SOL OFF) is commanded. The shift selector position and hydraulic state of latch valves
determines the range attained.
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
•
DTC P0964 indicates an open in the electrical circuit for the PCS2 solenoid. In addition to PCS2, HSD2 also
supplies power to solenoids PCS1, PCS3, and SS1. If DTC P0964 is accompanied by DTC P2727 (PCS1 open
circuit) and/or DTC P0968 (PCS3 open circuit), the open is most likely in the high side of the circuit.
•
You may have to drive the vehicle in order to experience a fault. Use the data obtained from failure records to
determine transmission range and/or certain vehicle operating variables such as temperature, run time etc. This
data can be useful in reproducing the failure mode when DTC was set.
•
Inspect the wiring for poor electrical connections at the TCM and transmission connector. Look for the
following conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
•
Inspect OEM wiring harness routing, look for possible contact points where chafing could occur leading to an
open or short circuit condition. Moving parts on the vehicle could be contacting the harness; this includes
parking brake drum, suspension components, etc.
•
When diagnosing for an intermittent short or open, massage the wiring harness while watching the test
equipment for a change.
Test Description
This DTC requires the use of the J 47275 TCM Breakout and J 47279 Transmission Breakout. The numbers below
refer to step numbers on the diagnostic table.
2. This step tests for the proper ignition voltage.
3. This step tests for an active DTC.
4. This step tests the OEM harness for an excessive voltage drop caused by open condition in either wire
171 or wire 152 of the OEM chassis harness.
6. This step tests for an open condition in the transmission internal harness.
7. This step tests for the proper PCS2 resistance.
6–218
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0964 Pressure Control Solenoid 2 (PCS2) Control Circuit Open
Step
1
2
3
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
1. Install the Allison DOC™ For PC–Service Tool. 9–18V (12V TCM)
18–32V (24V TCM)
2. Start the engine.
3. Record the failure records.
4. Monitor ignition voltage.
Is the voltage within the specified values?
1. Clear the DTC.
2. Start the engine and test drive the vehicle.
3. Attempt to duplicate the same conditions
observed in the failure records (range attained,
temperature, etc.).
Yes
Go to Step 2
Go to Step 3
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Resolve voltage
problem.
Go to Step 11
Go to Step 4
Go to
Diagnostic Aids
Go to Step 5
Go to Step 6
NOTE: This DTC is intended to detect an open
condition in the PCS2 electrical circuit.
4
Did DTC P0964 return?
NOTE: Review Section 4—Wire Test Procedures
before performing steps.
1. Turn OFF the ignition.
2. Install J 47275 TCM Breakout between the OEM
and TCM 80-way connectors.
3. Install J 47279 Transmission Breakout between
the OEM and transmission 20-way connectors.
4. Turn ON the ignition, leave engine OFF.
5. Using Allison DOC™ For PC–Service Tool, enter
Solenoid Test mode and command PCS2 ON.
6. Determine the voltage drop in the high side of the
PCS2 circuit as follows:
• At J 47275-1 TCM Overlay, measure voltage
between pin 71 and an isolated ground.
• At J 47279-1 Transmission Overlay, measure
voltage between pin 6 and an isolated ground.
• Subtract the two voltage measurements to
obtain the voltage drop in the circuit.
7. Determine the voltage drop in the low side of the
PCS2 circuit as follows:
• At J 47275-1 TCM Overlay, measure voltage
between pin 52 and an isolated ground.
• At J 47279-1 Transmission Overlay, measure
voltage between pin 5 and an isolated ground.
• Subtract the two voltage measurements to
obtain the voltage drop in the circuit.
NOTE: A voltage drop of more than 0.5V across
either circuit indicates an excessive voltage loss in
the OEM harness.
Did either high-side or low-side voltage drop exceed
0.5VDC?
Copyright © 2005 General Motors Corp.
6–219
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0964 Pressure Control Solenoid 2 (PCS2) Control Circuit Open (cont’d)
Step
5
6
7
8
9
10
11
6–220
Action
NOTE: The vehicle OEM has responsibility for all
external wiring harness repairs. Harness repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Coordinate with the vehicle OEM to repair or
replace the vehicle wiring.
Is the repair complete?
1. Turn OFF the ignition.
2. Disconnect the OEM 20-way connector from
J 47279 Transmission Breakout. Leave the
transmission 20-way connector connected to the
breakout.
3. Using a digital multimeter (DVOM), measure the
resistance between pin 5 and pin 6 of the
transmission 20-way connector.
Is the resistance within the specified value?
1. Remove the hydraulic control module assembly.
2. Disconnect PCS2 from the internal wiring
harness.
3. Using a DVOM, measure PCS2 resistance at pins
A and B.
Is resistance within the specified values?
Replace the internal wiring harness.
Is the replacement complete?
Replace PCS2.
Is the replacement complete?
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
Value(s)
Yes
Go to Step 11
No
Refer to Solenoid
Resistance Chart
(Appendix K)
Go to Step 10
Go to Step 7
Refer to Solenoid
Resistance Chart
(Appendix K)
Go to Step 8
Go to Step 9
Refer to TCM diagnostic procedure, Section 3–6.
Is Section 3–6 complete?
In order to verify your repair:
1. Clear the DTC.
2. Drive the vehicle under normal operating
conditions.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Go to Step 11
Go to Step 11
Go to Step 11
Begin the
diagnosis again.
Go to Step 1
System OK
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0966 Pressure Control Solenoid 2 (PCS2) Control Circuit Low
END VIEW OF
80-WAY CONNECTOR
END VIEW OF
20-WAY CONNECTOR
1
6
7
10
11
14
15
20
61
80
41
60
21
40
1
20
TRANSMISSION
HSD2
PCS1
PCS2
PCS3
SS1
TCM
6
4
5
9
10
WIRE 171
WIRE 136
WIRE 152
WIRE 133
WIRE 151
71
HSD2
V BATTERY
36
52
33
51
V09067.00.00
Circuit Description
Pressure Control Solenoid 2 (PCS2) is a normally open (N/O) solenoid used to apply the C2 clutch in fourth
through sixth range and the C3 clutch in reverse. The TCM commands the solenoid OFF to produce hydraulic
pressure in the clutch apply circuit. When PCS2 is commanded ON, the C2 clutch is released.
The TCM sends control current to PCS2 from High Side Driver 2 (HSD2) via wire 171. HSD2 is continuously ON
unless the TCM detects a fault condition. The TCM regulates the amount of current to PCS2 by switching PCS2
Low Side Driver (LSD) ON and OFF. Wire 152 completes the circuit between PCS2 and its LSD. DTC P0966
indicates that the TCM has detected a short-to-ground condition in the low side of PCS2 electrical circuit.
Conditions for Running the DTC
•
The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater
than 9V and less than 32V (24V TCM).
•
TCM initialization is in process or engine speed is greater than 200 rpm and less than 7500 rpm for 5 seconds.
Conditions for Setting the DTC
DTC P0966 is set when the TCM detects a short-to-ground in the PCS2 return circuit for more than 2 seconds.
Copyright © 2005 General Motors Corp.
6–221
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0966 Pressure Control Solenoid 2 (PCS2) Control Circuit Low
Actions Taken When the DTC Sets
When DTC P0966 is active, the following conditions will occur:
•
The CHECK TRANS light illuminates.
•
DTC is stored in TCM history.
•
Hydraulic default (SOL OFF) is commanded. The shift selector position and hydraulic state of latch valves
determines the range attained.
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
•
DTC P0966 indicates a short-to-ground in the electrical circuit for the PCS2 solenoid.
•
You may have to drive the vehicle in order to experience a fault. Use the data obtained from failure records to
determine transmission range and/or certain vehicle operating variables such as temperature, run time etc. This
data can be useful in reproducing the failure mode when DTC was set.
•
Inspect the wiring for poor electrical connections at the TCM and transmission connector. Look for the
following conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
•
Inspect OEM wiring harness routing, look for possible contact points where chafing could occur leading to an
open or short circuit condition. Moving parts on the vehicle could be contacting the harness; this includes
parking brake drum, suspension components, etc.
•
When diagnosing for an intermittent short or open, massage the wiring harness while watching the test
equipment for a change.
•
Advanced Troubleshooting (requires a frequency-capable digital multimeter, if available)—measure solenoid
LSD functionality as follows:
1. Install TCM breakout harness adapter J 47275 between the 80-way connectors of the TCM and OEM
harness.
2. Set up a frequency-capable digital multimeter, e.g. Fluke 87, to monitor frequency by selecting the
VOLTS-DC scale and depressing the HERTZ button once.
3. Connect the RED test lead to the solenoid low side pin at TCM breakout harness adapter J 47275. Connect the BLACK test lead to the isolated ground pin.
4. Use Allison DOC™ For PC–Service Tool solenoid test function to command the solenoid ON and OFF.
5. Frequency should read in the KILOHERTZ range when the driver is commanded ON. Frequency should
read 0 hertz when the driver is commanded OFF.
6–222
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
Test Description
This DTC requires the use of the J 47275 TCM Breakout and J 47279 Transmission Breakout. The numbers below
refer to step numbers on the diagnostic table.
2. This step tests for the proper ignition voltage.
3. This step tests for an active DTC.
4. This step tests for wire-to-wire shorts or a short-to-ground condition in wire 152.
6. This step tests for the wire-to-wire shorts or a short-to-ground in the internal transmission harness.
DTC P0966 Pressure Control Solenoid 2 (PCS2) Control Circuit Low
Step
1
2
3
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
1. Install the Allison DOC™ For PC–Service Tool. 9–18V (12V TCM)
18–32V (24V TCM)
2. Start the engine.
3. Record the failure records.
4. Monitor ignition voltage.
Is the voltage within the specified values?
1. Clear the DTC.
2. Start the engine and test drive the vehicle.
3. Attempt to duplicate the same conditions
observed in the failure records (range attained,
temperature, etc.).
Yes
Go to Step 2
Go to Step 3
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Resolve voltage
problem.
Go to Step 11
Go to Step 4
Go to
Diagnostic Aids
Go to Step 5
Go to Step 6
NOTE: This DTC is intended to detect a short-toground condition in the PCS2 electrical circuit.
4
Did DTC P0966 return?
NOTE: Review Section 4—Wire Test Procedures
before performing steps.
1. Turn OFF the ignition.
2. Disconnect the TCM 80-way connector.
3. Install the OEM-side of the 80-way connector to
the J 47275 TCM Breakout. Leave the TCM
disconnected.
4. Disconnect the transmission 20-way connector.
5. Inspect the routing of wire 152 in the chassis
harness between the TCM and transmission
connector.
6. At J 47275-1 TCM Overlay, test for wire-to-wire
shorts between pin 52 and all other pins in the
80-way connector, and short-to-ground between
pin 52 and chassis ground.
Were any wire-to-wire shorts or shorts-to-ground
wiring defects found?
Copyright © 2005 General Motors Corp.
6–223
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0966 Pressure Control Solenoid 2 (PCS2) Control Circuit Low (cont’d)
Step
5
6
Action
NOTE: The vehicle OEM has responsibility for all
external wiring harness repairs. Harness repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Value(s)
Coordinate with the vehicle OEM to repair or
replace the vehicle wiring.
Is the repair complete?
1. Turn OFF the ignition.
2. Install J 47279 Transmission Breakout to
transmission 20-way connector. Leave the OEM
harness disconnected.
3. Using a DVOM, test for wire-to-wire shorts
between pin 5 and pin 6 of the 20-way connector,
or shorts-to-ground between pin 5 and chassis
ground.
Yes
Go to Step 11
No
Go to Step 7
Go to Step 10
Go to Step 8
Go to Step 9
NOTE: The resistance value between pins 5 and 6
will read normal solenoid resistance. The resistance
between pins 5 and 4, between 5 and 9, and between
pins 5 and 10 will be twice normal solenoid
resistance. Refer to Solenoid Resistance chart for
these values.
7
8
9
10
11
6–224
Were any wire-to-wire shorts or shorts-to-ground
found?
1. Remove the hydraulic control module assembly.
2. Inspect the internal harness for wire-to-wire
shorts or shorts-to-ground.
Were any wire-to-wire shorts or shorts-to-ground
found?
Repair or replace the internal wiring harness.
Is the repair complete?
Replace PCS2.
Is the replacement complete?
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
Refer to TCM diagnostic procedure, Section 3–6.
Is Section 3–6 complete?
In order to verify your repair:
1. Clear the DTC.
2. Drive the vehicle under normal operating
conditions.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Go to Step 11
Go to Step 11
Go to Step 11
Begin the
diagnosis again.
Go to Step 1
System OK
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0967 Pressure Control Solenoid 2 (PCS2) Control Circuit High
END VIEW OF
80-WAY CONNECTOR
END VIEW OF
20-WAY CONNECTOR
1
6
7
10
11
14
15
20
61
80
41
60
21
40
1
20
TRANSMISSION
HSD2
PCS1
PCS2
PCS3
SS1
TCM
6
4
5
9
10
WIRE 171
WIRE 136
WIRE 152
WIRE 133
WIRE 151
71
HSD2
V BATTERY
36
52
33
51
V09067.00.00
Circuit Description
Pressure Control Solenoid 2 (PCS2) is a normally open (N/O) solenoid used to apply the C2 clutch in fourth
through sixth range and the C3 clutch in reverse. The TCM commands the solenoid OFF to produce hydraulic
pressure in the clutch apply circuit. When PCS2 is commanded ON, the C2 clutch is released.
The TCM sends control current to PCS2 from High Side Driver 2 (HSD2) via wire 171. HSD2 is continuously ON
unless the TCM detects a fault condition. The TCM regulates the amount of current to PCS2 by switching PCS2
Low Side Driver (LSD) ON and OFF. Wire 152 completes the circuit between PCS2 and its LSD. DTC P0967
indicates that the TCM has detected a short-to-battery condition in the low side of PCS2 electrical circuit.
Conditions for Running the DTC
•
The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater
than 9V and less than 32V (24V TCM).
•
TCM initialization is in process or engine speed is greater than 200 rpm and less than 7500 rpm for 5 seconds.
Conditions for Setting the DTC
DTC P0967 is set when the TCM detects a short-to-battery in the PCS2 return circuit for more than 2 seconds.
Copyright © 2005 General Motors Corp.
6–225
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0967 Pressure Control Solenoid 2 (PCS2) Control Circuit High
Actions Taken When the DTC Sets
When DTC P0967 is active, the following conditions will occur:
•
The CHECK TRANS light illuminates.
•
DTC is stored in TCM history.
•
Hydraulic default (SOL OFF) is commanded. The shift selector position and hydraulic state of latch valves
determines the range attained.
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
•
DTC P0967 indicates a short-to-battery in the electrical circuit for the PCS2 solenoid.
•
You may have to drive the vehicle in order to experience a fault. Use the data obtained from failure records to
determine transmission range and/or certain vehicle operating variables such as temperature, run time etc. This
data can be useful in reproducing the failure mode when DTC was set.
•
Inspect the wiring for poor electrical connections at the TCM and transmission connector. Look for the
following conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
•
Inspect OEM wiring harness routing, look for possible contact points where chafing could occur leading to an
open or short circuit condition. Moving parts on the vehicle could be contacting the harness; this includes
parking brake drum, suspension components, etc.
•
When diagnosing for an intermittent short or open, massage the wiring harness while watching the test
equipment for a change.
•
Advanced Troubleshooting (requires a frequency-capable digital multimeter, if available)—measure solenoid
LSD functionality as follows:
1. Install TCM breakout harness adapter J 47275 between the 80-way connectors of the TCM and OEM
harness.
2. Set up a frequency-capable digital multimeter, e.g. Fluke 87, to monitor frequency by selecting the
VOLTS-DC scale and depressing the HERTZ button once.
3. Connect the RED test lead to the solenoid low side pin at TCM breakout harness adapter J 47275. Connect the BLACK test lead to the isolated ground pin.
4. Use Allison DOC™ For PC–Service Tool solenoid test function to command the solenoid ON and OFF.
5. Frequency should read in the KILOHERTZ range when the driver is commanded ON. Frequency should
read 0 hertz when the driver is commanded OFF.
6–226
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
Test Description
This DTC requires the use of the J 47275 TCM Breakout and J 47279 Transmission Breakout. The numbers below
refer to step numbers on the diagnostic table.
2. This step tests for the proper ignition voltage.
3. This step tests for an active DTC.
4. This step tests for wire-to-wire shorts between wire 152 and other wires in the OEM chassis harness.
6. This step tests for the wire-to-wire shorts in the transmission internal harness.
DTC P0967 Pressure Control Solenoid 2 (PCS2) Control Circuit High
Step
1
2
3
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
1. Install the Allison DOC™ For PC–Service Tool. 9–18V (12V TCM)
18–32V (24V TCM)
2. Start the engine.
3. Record the failure records.
4. Monitor ignition voltage.
Is the voltage within the specified values?
1. Clear the DTC.
2. Start the engine and test drive the vehicle.
3. Attempt to duplicate the same conditions
observed in the failure records (range attained,
temperature, etc.).
Yes
Go to Step 2
Go to Step 3
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Resolve voltage
problem.
Go to Step 11
Go to Step 4
Go to
Diagnostic Aids
Go to Step 5
Go to Step 6
NOTE: This DTC is intended to detect a short-toBattery condition in the PCS2 electrical circuit.
4
Did DTC P0966 return?
NOTE: Review Section 4—Wire Test Procedures
before performing steps.
1. Turn OFF the ignition.
2. Disconnect the TCM 80-way connector.
3. Install the OEM-side of the 80-way connector to
the J 47275 TCM Breakout. Leave the TCM
disconnected.
4. Disconnect the transmission 20-way connector.
5. Inspect the routing of wires 171 and 152 in the
chassis harness between the TCM and
transmission connector.
6. At J 47275-1 TCM Overlay, test for wire-to-wire
shorts between pin 52 and all other pins in the
80-way connector, and short-to-ground between
pin 52 and chassis ground.
Were any wire-to-wire shorts or shorts-to-ground
wiring defects found?
Copyright © 2005 General Motors Corp.
6–227
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0967 Pressure Control Solenoid 2 (PCS2) Control Circuit High (cont’d)
Step
5
6
Action
NOTE: The vehicle OEM has responsibility for all
external wiring harness repairs. Harness repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Value(s)
Coordinate with the vehicle OEM to repair or
replace the vehicle wiring.
Is the repair complete?
1. Turn OFF the ignition.
2. Install J 47279 Transmission Breakout to
transmission 20-way connector. Leave the OEM
harness disconnected.
3. Using a DVOM, test for wire-to-wire shorts
between pin 5 and all other pins in the 20-way
connector.
Yes
Go to Step 11
No
Go to Step 7
Go to Step 10
Go to Step 8
Go to Step 9
NOTE: The resistance value between pins 5 and 6
will read normal solenoid resistance. The resistance
between pins 5 and 4, between 5 and 9, and between
pins 5 and 10 will be twice normal solenoid
resistance. Refer to Solenoid Resistance chart for
these values.
7
8
9
10
11
6–228
Were any wire-to-wire shorts found?
1. Remove the hydraulic control module assembly.
2. Inspect the internal harness for wire-to-wire
shorts or shorts-to-ground.
Were any wire-to-wire shorts found?
Repair or Replace the internal wiring harness.
Is the repair complete?
Replace PCS2.
Is the replacement complete?
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
Refer to Solenoid
Resistance Chart
(Appendix K)
Refer to TCM diagnostic procedure, Section 3–6.
Is Section 3–6 complete?
In order to verify your repair:
1. Clear the DTC.
2. Drive the vehicle under normal operating
conditions.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Go to Step 11
Go to Step 11
Go to Step 11
Begin the
diagnosis again.
Go to Step 1
System OK
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0968 Pressure Control Solenoid 3 (PCS3) Control Circuit Open
END VIEW OF
80-WAY CONNECTOR
END VIEW OF
20-WAY CONNECTOR
1
6
7
10
11
14
15
20
61
80
41
60
21
40
1
20
TRANSMISSION
HSD2
PCS1
PCS2
PCS3
SS1
TCM
WIRE 171
6
WIRE 136
4
WIRE 152
5
WIRE 133
9
10
WIRE 151
71
HSD2
V BATTERY
36
52
33
51
V09067.00.00
Circuit Description
Pressure Control Solenoid 3 (PCS3) is a normally closed (N/C) solenoid used to apply the C5 clutch in reverse,
neutral and first and to apply the C3 clutch in third and fifth ranges. The TCM commands the solenoid ON to
produce hydraulic pressure in the clutch apply circuit. When PCS3 is commanded OFF, the clutch pressure is
released.
The TCM sends control current to PCS3 from High Side Driver 2 (HSD2) via wire 171. HSD2 is continuously ON
unless the TCM detects a fault condition. The TCM regulates the amount of current to PCS3 by switching PCS3
Low Side Driver (LSD) ON and OFF. Wire 133 completes the circuit between PCS3 and its LSD. DTC P0968
indicates that the TCM has detected an open condition in PCS3 electrical circuit. The open condition may exist in
the high side (wire 171) or low side (wire 133).
Conditions for Running the DTC
•
The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater
than 9V and less than 32V (24V TCM).
•
TCM initialization is in process or engine speed is greater than 200 rpm and less than 7500 rpm for 5 seconds.
Conditions for Setting the DTC
DTC P0968 is set when the TCM detects an open circuit on the PCS3 return circuit for more than 2 seconds.
Copyright © 2005 General Motors Corp.
6–229
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0968 Pressure Control Solenoid 3 (PCS3) Control Circuit Open
Actions Taken When the DTC Sets
When DTC P0968 is active, the following conditions will occur:
•
The CHECK TRANS light illuminates.
•
DTC is stored in TCM history.
•
Hydraulic default (SOL OFF) is commanded. The shift selector position and hydraulic state of latch valves
determines the range attained.
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
•
DTC P0968 indicates an open in the electrical circuit for the PCS3 solenoid. In addition to PCS3, HSD2 also
supplies power to solenoids PCS1, PCS2, and SS1. If DTC P0968 is accompanied by DTC P2727 (PCS1 open
circuit) and/or DTC P0964 (PCS2 open circuit), the open is most likely in the high side of the circuit.
•
You may have to drive the vehicle in order to experience a fault. Use the data obtained from failure records to
determine transmission range and/or certain vehicle operating variables such as temperature, run time etc. This
data can be useful in reproducing the failure mode when DTC was set.
•
Inspect the wiring for poor electrical connections at the TCM and transmission connector. Look for the
following conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
•
Inspect OEM wiring harness routing, look for possible contact points where chafing could occur leading to an
open or short circuit condition. Moving parts on the vehicle could be contacting the harness; this includes
parking brake drum, suspension components, etc.
•
When diagnosing for an intermittent short or open, massage the wiring harness while watching the test
equipment for a change.
Test Description
This DTC requires the use of the J 47275 TCM Breakout and J 47279 Transmission Breakout. The numbers below
refer to step numbers on the diagnostic table.
2. This step tests for the proper ignition voltage.
3. This step tests for an active DTC.
4. This step tests the OEM harness for an excessive voltage drop caused by an open condition in either wire
171 or wire 133 of the OEM chassis harness.
6. This step tests for an open condition in the transmission internal harness.
7. This step tests for the proper PCS3 resistance.
6–230
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0968 Pressure Control Solenoid 3 (PCS3) Control Circuit Open
Step
1
2
3
4
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
1. Install the Allison DOC™ For PC–Service Tool. 9–18V(12V TCM)
2. Start the engine.
18–32V (24V TCM)
3. Record the failure records.
4. Monitor ignition voltage.
Is the voltage within the specified values?
1. Clear the DTC.
2. Start the engine and test drive the vehicle.
3. Attempt to duplicate the same conditions
observed in the failure records (range attained,
temperature, etc.).
NOTE: This DTC is intended to detect an open
condition in the PCS3 electrical circuit.
Did DTC P0968 return?
NOTE: Review Section 4—Wire Test Procedures
before performing steps.
1. Turn OFF the ignition.
2. Install J 47275 TCM Breakout between the OEM
and TCM 80-way connectors.
3. Install J 47279 Transmission Breakout between
the OEM and transmission 20-way connectors.
4. Turn ignition ON, leave engine OFF.
5. Using Allison DOC™ For PC–Service Tool, enter
Solenoid Test mode and command PCS3 ON.
6. Determine the voltage drop in the high side of the
PCS3 circuit as follows:
• At J 47275-1 TCM Overlay, measure voltage
between pin 71 and an isolated ground.
• At J 47279-1 Transmission Overlay, measure
voltage between pin 6 and isolated ground.
• Subtract the two voltage measurements to
obtain the voltage drop in the circuit.
7. Determine the voltage drop in the low side of the
PCS3 circuit as follows:
• At J 47275-1 TCM Overlay, measure voltage
between pin 33 and an isolated ground.
• At J 47279-1 Transmission Overlay, measure
voltage between pin 9 and isolated ground.
• Subtract the two voltage measurements to
obtain the voltage drop in the circuit.
Yes
Go to Step 2
Go to Step 3
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Resolve voltage
problem.
Go to Step 11
Go to Step 4
Go to
Diagnostic Aids
Go to Step 5
Go to Step 6
NOTE: A voltage drop of more than 0.5V across
either circuit indicates an excessive voltage loss in
the OEM harness.
Did either high-side or low-side voltage drop exceed
0.5VDC?
Copyright © 2005 General Motors Corp.
6–231
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0968 Pressure Control Solenoid 3 (PCS3) Control Circuit Open (cont’d)
Step
5
6
7
8
9
10
11
6–232
Action
NOTE: The vehicle OEM has responsibility for all
external wiring harness repairs. Harness repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Coordinate with the vehicle OEM to repair or
replace the vehicle wiring.
Is the repair complete?
1. Turn OFF the ignition.
2. Disconnect the OEM 20-way connector from
J 47279 Transmission Breakout. Leave the
transmission 20-way connector connected to the
breakout.
3. Using a DVOM, measure the resistance between
pin 6 and pin 9 of the transmission 20-way
connector.
Is the resistance within the specified value?
1. Remove the hydraulic control module assembly.
2. Disconnect PCS3 from the internal wiring
harness.
3. Using a DVOM, measure PCS3 resistance at pins
A and B.
Is resistance within the specified values?
Replace the internal wiring harness.
Is the replacement complete?
Replace PCS3.
Is the replacement complete?
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
Value(s)
Yes
Go to Step 11
No
Refer to Solenoid
Resistance Chart
(Appendix K)
Go to Step 10
Go to Step 7
Refer to Solenoid
Resistance Chart
(Appendix K)
Go to Step 8
Go to Step 9
Refer to TCM diagnostic procedure, Section 3–6.
Is Section 3–6 complete?
In order to verify your repair:
1. Clear the DTC.
2. Drive the vehicle under normal operating
conditions.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Go to Step 11
Go to Step 11
Go to Step 11
Begin the
diagnosis again.
Go to Step 1
System OK
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0970 Pressure Control Solenoid 3 (PCS3) Control Circuit Low
END VIEW OF
80-WAY CONNECTOR
END VIEW OF
20-WAY CONNECTOR
1
6
7
10
11
14
15
20
61
80
41
60
21
40
1
20
TRANSMISSION
HSD2
PCS1
PCS2
PCS3
SS1
TCM
6
4
5
9
10
WIRE 171
WIRE 136
WIRE 152
WIRE 133
WIRE 151
71
HSD2
V BATTERY
36
52
33
51
V09067.00.00
Circuit Description
Pressure Control Solenoid 3 (PCS3) is a normally closed (N/C) solenoid used to apply the C5 clutch in reverse,
neutral and first; and to apply the C3 clutch in third and fifth ranges. The TCM commands the solenoid ON to produce
hydraulic pressure in the clutch apply circuit. When PCS3 is commanded OFF, the clutch pressure is released.
The TCM sends control current to PCS3 from High Side Driver 2 (HSD2) via wire 171. HSD2 is continuously ON
unless the TCM detects a fault condition. The TCM regulates the amount of current to PCS3 by switching PCS3
Low Side Driver (LSD) ON and OFF. Wire 133 completes the circuit between PCS3 and its LSD. DTC P0970
indicates that the TCM has detected a short-to-ground condition in the low side of PCS electrical circuit.
Conditions for Running the DTC
•
The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater
than 9V and less than 32V (24V TCM).
•
TCM initialization is in process or engine speed is greater than 200 rpm and less than 7500 rpm for 5 seconds.
Conditions for Setting the DTC
DTC P0970 is set when the TCM detects a short-to-ground in the PCS3 return circuit for more than 2 seconds.
Copyright © 2005 General Motors Corp.
6–233
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0970 Pressure Control Solenoid 3 (PCS3) Control Circuit Low
Actions Taken When the DTC Sets
When DTC P0970 is active, the following conditions will occur:
•
The CHECK TRANS light illuminates.
•
DTC is stored in TCM history.
•
Hydraulic default (SOL OFF) is commanded. The shift selector position and hydraulic state of latch valves
determines the range attained.
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
•
DTC P0970 indicates a short-to-ground in the electrical circuit for the PCS3 solenoid.
•
You may have to drive the vehicle in order to experience a fault. Use the data obtained from failure records to
determine transmission range and/or certain vehicle operating variables such as temperature, run time etc. This
data can be useful in reproducing the failure mode when DTC was set.
•
Inspect the wiring for poor electrical connections at the TCM and transmission connector. Look for the
following conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
•
Inspect OEM wiring harness routing, look for possible contact points where chafing could occur leading to an
open or short circuit condition. Moving parts on the vehicle could be contacting the harness; this includes
parking brake drum, suspension components, etc.
•
When diagnosing for an intermittent short or open, massage the wiring harness while watching the test
equipment for a change.
•
Advanced Troubleshooting (requires a frequency-capable digital multimeter, if available)—measure solenoid
LSD functionality as follows:
1. Install TCM breakout harness adapter J 47275 between the 80-way connectors of the TCM and OEM
harness.
2. Set up a frequency-capable digital multimeter, e.g. Fluke 87, to monitor frequency by selecting the
VOLTS-DC scale and depressing the HERTZ button once.
3. Connect the RED test lead to the solenoid low side pin at TCM breakout harness adapter J 47275. Connect the BLACK test lead to the isolated ground pin.
4. Use Allison DOC™ For PC–Service Tool solenoid test function to command the solenoid ON and OFF.
5. Frequency should read in the KILOHERTZ range when the driver is commanded ON. Frequency should
read 0 hertz when the driver is commanded OFF.
6–234
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
Test Description
This DTC requires the use of the J 47275 TCM Breakout and J 47279 Transmission Breakout. The numbers below
refer to step numbers on the diagnostic table.
2. This step tests for the proper ignition voltage.
3. This step tests for an active DTC.
4. This step tests for wire-to-wire shorts or a short-to-ground condition in wire 133.
6. This step tests for the wire-to-wire shorts or a short-to-ground in the internal transmission harness.
DTC P0970 Pressure Control Solenoid 3 (PCS3) Control Circuit Low
Step
1
2
3
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
1. Install the Allison DOC™ For PC–Service Tool. 9–18V (12V TCM)
18–32V (24V TCM)
2. Start the engine.
3. Record the failure records.
4. Monitor ignition voltage.
Is the voltage within the specified values?
1. Clear the DTC.
2. Start the engine and test drive the vehicle.
3. Attempt to duplicate the same conditions
observed in the failure records (range attained,
temperature, etc.).
Yes
Go to Step 2
Go to Step 3
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Resolve voltage
problem.
Go to Step 11
Go to Step 4
Go to
Diagnostic Aids
Go to Step 5
Go to Step 6
NOTE: This DTC is intended to detect a short-toground condition in the PCS3 electrical circuit.
4
Did DTC P0970 return?
NOTE: Review Section 4—Wire Test Procedures
before performing steps.
1. Turn OFF the ignition.
2. Disconnect the TCM 80-way connector.
3. Install the OEM-side of the 80-way connector to
the J 47275 TCM Breakout. Leave the TCM-side
disconnected.
4. Disconnect the transmission 20-way connector.
5. Inspect the routing of wire 133 in the chassis
harness between the TCM and the transmission
connector.
6. At J 47275-1 TCM Overlay, test for wire-to-wire
shorts between pin 33 and all other pins in the
80-way connector, and shorts-to-ground between
pin 33 and chassis ground.
Were any wire-to-wire shorts or shorts-to-ground
found?
Copyright © 2005 General Motors Corp.
6–235
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0970 Pressure Control Solenoid 3 (PCS3) Control Circuit Low (cont’d)
Step
5
6
Action
NOTE: The vehicle OEM has responsibility for all
external wiring harness repairs. Harness repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Value(s)
Coordinate with the vehicle OEM to repair or
replace the vehicle wiring.
Is the repair complete?
1. Turn OFF the ignition.
2. Install J 47279 Transmission Breakout to the
transmission 20-way connector. Leave the OEM
harness disconnected.
3. Using a DVOM, test for wire-to-wire shorts
between pin 9 and all other pins in the 20-way
connector, and shorts-to-ground between pin 9
and chassis ground.
Yes
Go to Step 11
No
Go to Step 7
Go to Step 10
Go to Step 8
Go to Step 9
NOTE: The resistance value between pins 9 and 6
will read normal solenoid resistance. The resistance
value between pins 9 and 4, between pins 9 and 5,
and between pins 9 and 10 will be twice normal
solenoid resistance. Refer to Solenoid Resistance
chart for these values.
7
8
9
10
11
6–236
Were wire-to-wire or shorts-to-ground found?
1. Remove the hydraulic control module assembly.
2. Inspect the internal harness for wire-to-wire
shorts or shorts-to-ground.
Were wire-to-wire or shorts-to-ground found?
Replace the internal wiring harness.
Is the replacement complete?
Replace PCS3.
Is the replacement complete?
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
Refer to TCM diagnostic procedure, Section 3–6.
Is Section 3–6 complete?
In order to verify your repair:
1. Clear the DTC.
2. Drive the vehicle under normal operating
conditions.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Go to Step 11
Go to Step 11
Go to Step 11
Begin the
diagnosis again.
Go to Step 1
System OK
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0971 Pressure Control Solenoid 3 (PCS3) Control Circuit High
END VIEW OF
80-WAY CONNECTOR
END VIEW OF
20-WAY CONNECTOR
1
6
7
10
11
14
15
20
61
80
41
60
21
40
1
20
TRANSMISSION
HSD2
PCS1
PCS2
PCS3
SS1
TCM
6
4
5
9
10
WIRE 171
WIRE 136
WIRE 152
WIRE 133
WIRE 151
71
HSD2
V BATTERY
36
52
33
51
V09067.00.00
Circuit Description
Pressure Control Solenoid 3 (PCS3) is a normally closed (N/C) solenoid used to apply the C5 clutch in reverse,
neutral and first and to apply the C3 clutch in third and fifth ranges. The TCM commands the solenoid ON to
produce hydraulic pressure in the clutch apply circuit. When PCS3 is commanded OFF, the clutch pressure is
released.
The TCM sends control current to PCS3 from High Side Driver 2 (HSD2) via wire 171. HSD2 is continuously ON
unless the TCM detects a fault condition. The TCM regulates the amount of current to PCS3 by switching PCS3
Low Side Driver (LSD) ON and OFF. Wire 133 completes the circuit between PCS3 and its LSD. DTC P0971
indicates that the TCM has detected a short-to-battery condition in the low side of PCS electrical circuit.
Conditions for Running the DTC
•
The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater
than 9V and less than 32V (24V TCM).
•
TCM initialization is in process or engine speed is greater than 200 rpm and less than 7500 rpm for 5 seconds.
Conditions for Setting the DTC
DTC P0971 is set when the TCM detects a short-to-battery in the PCS3 return circuit for more than 2 seconds.
Copyright © 2005 General Motors Corp.
6–237
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0971 Pressure Control Solenoid 3 (PCS3) Control Circuit High
Actions Taken When the DTC Sets
When DTC P0971 is active, the following conditions will occur:
•
The CHECK TRANS light illuminates.
•
DTC is stored in TCM history.
•
Hydraulic default (SOL OFF) is commanded. The shift selector position and hydraulic state of latch valves
determines the range attained.
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
•
DTC P0971 indicates a short-to-battery in the electrical circuit for the PCS3 solenoid.
•
You may have to drive the vehicle in order to experience a fault. Use the data obtained from failure records to
determine transmission range and/or certain vehicle operating variables such as temperature, run time etc. This
data can be useful in reproducing the failure mode when DTC was set.
•
Inspect the wiring for poor electrical connections at the TCM and transmission connector. Look for the
following conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
•
Inspect OEM wiring harness routing, look for possible contact points where chafing could occur leading to an
open or short circuit condition. Moving parts on the vehicle could be contacting the harness; this includes
parking brake drum, suspension components, etc.
•
When diagnosing for an intermittent short or open, massage the wiring harness while watching the test
equipment for a change.
•
Advanced Troubleshooting (requires a frequency-capable digital multimeter, if available)—measure solenoid
LSD functionality as follows:
1. Install TCM breakout harness adapter J 47275 between the 80-way connectors of the TCM and OEM
harness.
2. Set up a frequency-capable digital multimeter, e.g. Fluke 87, to monitor frequency by selecting the
VOLTS-DC scale and depressing the HERTZ button once.
3. Connect the RED test lead to the solenoid low side pin at TCM breakout harness adapter J 47275. Connect the BLACK test lead to the isolated ground pin.
4. Use Allison DOC™ For PC–Service Tool solenoid test function to command the solenoid ON and OFF.
5. Frequency should read in the KILOHERTZ range when the driver is commanded ON. Frequency should
read 0 hertz when the driver is commanded OFF.
6–238
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
Test Description
This DTC requires the use of the J 47275 TCM Breakout and J 47279 Transmission Breakout. The numbers below
refer to step numbers on the diagnostic table.
2. This step tests for the proper ignition voltage.
3. This step tests for an active DTC.
4. This step tests for wire-to-wire shorts between wire 133 and other wires in the OEM chassis harness.
6. This step tests for the wire-to-wire shorts in the transmission internal harness.
DTC P0971 Pressure Control Solenoid 3 (PCS3) Control Circuit High
Step
1
2
3
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
1. Install the Allison DOC™ For PC–Service Tool. 9–18V (12V TCM)
18–32V (24V TCM)
2. Start the engine.
3. Record the failure records.
4. Monitor ignition voltage.
Is the voltage within the specified values?
1. Clear the DTC.
2. Start the engine and test drive the vehicle.
3. Attempt to duplicate the same conditions
observed in the failure records (range attained,
temperature, etc.).
Yes
Go to Step 2
Go to Step 3
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Resolve voltage
problem.
Go to Step 11
Go to Step 4
Go to
Diagnostic Aids
Go to Step 5
Go to Step 6
NOTE: This DTC is intended to detect short-tobattery condition in the PCS3 electrical circuit.
4
Did DTC P0971 return?
NOTE: Review Section 4—Wire Test Procedures
before performing steps.
1. Turn OFF the ignition.
2. Disconnect the TCM 80-way connector.
3. Install the OEM-side of the 80-way connector to
the J 47275 TCM Breakout. Leave the TCM
disconnected.
4. Disconnect the transmission 20-way connector.
5. Inspect the routing of wires 177 and 133 in the
chassis harness between the TCM and the
transmission connector.
6. At J 47275-1 TCM Overlay, test for wire-to-wire
shorts between pin 33 and all other pins in the
80-way connector, and shorts-to-ground between
pin 33 and chassis ground.
Were any wire-to-wire shorts found?
Copyright © 2005 General Motors Corp.
6–239
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0971 Pressure Control Solenoid 3 (PCS3) Control Circuit High (cont’d)
Step
5
6
Action
NOTE: The vehicle OEM has responsibility for all
external wiring harness repairs. Harness repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Coordinate with the vehicle OEM to repair or
replace the vehicle wiring.
Is the repair complete?
1. Turn OFF the ignition.
2. Install J 47279 Transmission Breakout to the
transmission 20-way connector. Leave the OEM
harness disconnected.
3. Using a DVOM, test for wire-to-wire shorts
between pin 9 and all other pins in the 20-way
connector.
Value(s)
Yes
Go to Step 11
No
Refer to Solenoid
Resistance Chart
(Appendix K)
Go to Step 7
Go to Step 10
Go to Step 8
Go to Step 9
NOTE: The resistance value between pins 9 and 6
will read normal solenoid resistance. The resistance
value between pins 9 and 4, between pins 9 and 5,
and between pins 9 and 10 will be twice normal
solenoid resistance. Refer to Solenoid Resistance
chart for these values.
7
8
9
10
11
6–240
Were wire-to-wire shorts found?
1. Remove the hydraulic control module assembly.
2. Inspect the internal harness for wire-to-wire
shorts.
Were wire-to-wire shorts found?
Replace the internal wiring harness.
Is the replacement complete?
Replace or repair PCS3.
Is the replacement complete?
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
Refer to TCM diagnostic procedure, Section 3–6.
Is Section 3–6 complete?
In order to verify your repair:
1. Clear the DTC.
2. Drive the vehicle under normal operating
conditions.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Go to Step 11
Go to Step 11
Go to Step 11
Begin the
diagnosis again.
Go to Step 1
System OK
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0973 Shift Solenoid 1 (SS1) Control Circuit Low
END VIEW OF
80-WAY CONNECTOR
END VIEW OF
20-WAY CONNECTOR
1
6
7
10
11
14
15
20
61
80
41
60
21
40
1
20
TRANSMISSION
HSD2
PCS1
PCS2
PCS3
SS1
TCM
6
4
5
9
10
WIRE 171
WIRE 136
WIRE 152
WIRE 133
WIRE 151
71
HSD2
V BATTERY
36
52
33
51
V09067.00.00
Circuit Description
Shift Solenoid 1 (SS1) is a normally closed (N/C) solenoid used to properly position the C1 and C2 latch valves in
forward ranges. The TCM commands the solenoid ON to supply control main pressure to the C1 and C2 latch
valves. When solenoid SS1 is commanded OFF, control main pressure is relieved from the C1 and C2 latch valves.
The TCM sends control current to solenoid SS1 from High Side Driver 2 (HSD2) via wire 171. HSD2 is
continuously ON unless the TCM detects a fault condition. The TCM energizes SS1 by switching the solenoid’s
Low Side Driver (LSD) ON. Wire 151 completes the circuit between SS1 and its LSD. DTC P0973 indicates that
the TCM has detected a short-to-ground or open circuit condition in the low side of SS1 electrical circuit.
Conditions for Running the DTC
•
The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater
than 9V and less than 32V (24V TCM).
•
TCM initialization is in process or engine speed is greater than 200 rpm and less than 7500 rpm for 5 seconds.
Conditions for Setting the DTC
DTC P0973 is set when the TCM detects a short-to-ground or open condition in the SS1 return circuit for more
than 125 milliseconds.
Copyright © 2005 General Motors Corp.
6–241
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0973 Shift Solenoid 1 (SS1) Control Circuit Low
Actions Taken When the DTC Sets
When DTC P0973 is active, the following conditions will occur:
•
The CHECK TRANS light illuminates.
•
DTC is stored in TCM history.
•
Hydraulic default (SOL OFF) is commanded. The shift selector position and hydraulic state of latch valves
determines the range attained.
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
•
DTC P0973 indicates a short-to-ground or an open condition in the electrical circuit for the SS1 solenoid.
•
You may have to drive the vehicle in order to experience a fault. Use the data obtained from failure records to
determine transmission range and/or certain vehicle operating variables such as temperature, run time etc. This
data can be useful in reproducing the failure mode when DTC was set.
•
Inspect the wiring for poor electrical connections at the TCM and transmission connector. Look for the
following conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
•
Inspect OEM wiring harness routing, look for possible contact points where chafing could occur leading to an
open or short circuit condition. Moving parts on the vehicle could be contacting the harness; this includes
parking brake drum, suspension components, etc.
•
When diagnosing for an intermittent short or open, massage the wiring harness while watching the test
equipment for a change.
•
Advanced Troubleshooting (requires a frequency-capable digital multimeter, if available)—measure solenoid
LSD functionality as follows:
1. Install TCM breakout harness adapter J 47275 between the 80-way connectors of the TCM and OEM
harness.
2. Set up a frequency-capable digital multimeter, e.g. Fluke 87, to monitor frequency by selecting the
VOLTS-DC scale and depressing the HERTZ button once.
3. Connect the RED test lead to the solenoid low side pin at TCM breakout harness adapter J 47275. Connect the BLACK test lead to the isolated ground pin.
4. Use Allison DOC™ For PC–Service Tool solenoid test function to command the solenoid ON and OFF.
5. Frequency should read in the KILOHERTZ range when the driver is commanded ON. Frequency should
read 0 hertz when the driver is commanded OFF. NOTE: A 1000 hertz test pulse may be present in
the SS1 circuit.
6–242
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
Test Description
This DTC requires the use of the J 47275 TCM Breakout and J 47279 Transmission Breakout. The numbers below
refer to step numbers on the diagnostic table.
2. This step tests for the proper ignition voltage.
3. This step tests for an active DTC.
4. This step tests for the OEM harness for an excessive voltage drop caused by an open condition in either
wire 171 or wire 151 of the OEM chassis harness.
5. This step tests for wire-to-wire shorts or a short-to-ground condition in wire 151.
7. This step tests for wire-to-wire shorts or a short-to-ground or an open in the internal transmission harness.
DTC P0973 Shift Solenoid 1 (SS1) Control Circuit Low
Step
1
2
3
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
1. Install the Allison DOC™ For PC–Service Tool. 9–18V (12V TCM)
18–32V (24V TCM)
2. Start the engine.
3. Record the failure records.
4. Monitor ignition voltage.
Is the voltage within the specified values?
1. Clear the DTC.
2. Start the engine and test drive the vehicle.
3. Attempt to duplicate the same conditions
observed in the failure records (range attained,
temperature, etc.).
Yes
Go to Step 2
Go to Step 3
Go to Step 4
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Resolve voltage
problem.
Go to Step 11
Go to
Diagnostic Aids
NOTE: This DTC is intended to detect a short-toground or open condition in the SS1 electrical
circuit.
Did DTC P0973 return?
Copyright © 2005 General Motors Corp.
6–243
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0973 Shift Solenoid 1 (SS1) Control Circuit Low (cont’d)
Step
4
Action
NOTE: Review Section 4–Wire Test Procedures
before performing steps.
1. Turn ignition OFF.
2. Install J 47275 TCM Breakout between the OEM
and TCM 80-way connectors.
3. Install J 47279 Transmission Breakout between
the OEM and transmission 20-way connectors.
4. Turn ignition ON, leave engine OFF.
5. Using Allison DOC™ For PC–Service Tool enter
Solenoid Test mode and command solenoid SS1
ON.
6. Determine the voltage drop in the high side of the
SS1 circuit as follows:
• At J 47275-1 TCM Overlay, measure voltage
between pin 71 and an isolated ground.
• At J 47279-1 Transmission Overlay, measure
voltage between pin 6 and ground.
• Subtract the two voltage measurements to
obtain the voltage drop in the circuit.
7. Determine the voltage drop in the low side of the
SS1 circuit as follows:
• At J 47275-1 TCM Overlay, measure voltage
between pin 51 and an isolated ground.
• At J 47279-1 Transmission Overlay, measure
voltage between pin 10 and ground.
• Subtract the two voltage measurements to
obtain the voltage drop in the circuit.
Value(s)
Yes
Go to Step 6
No
Go to Step 5
Go to Step 6
Go to Step 7
NOTE: A voltage drop of more than 0.5V across
either circuit indicates an excessive voltage loss in
the OEM harness.
5
6–244
Did either high-side or low-side voltage drop exceed
0.5 VDC?
NOTE: Review Section 4—Wire Test Procedures
before performing steps.
1. Turn OFF the ignition.
2. Disconnect the TCM 80-way connector.
3. Install the OEM-side of the 80-way connector to
the J 47275 TCM Breakout. Leave the TCM
disconnected.
4. Disconnect the transmission 20-way connector.
5. Inspect the routing of wire 151 in the chassis
harness between the TCM and the transmission
connector.
6. At J 47275-1 TCM Overlay, test for wire-to-wire
shorts between pin 51 and all other pins in the
80-way connector.
Were any wire-to-wire shorts or shorts-to-ground
found?
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0973 Shift Solenoid 1 (SS1) Control Circuit Low (cont’d)
Step
6
7
Action
NOTE: The vehicle OEM has responsibility for all
external wiring harness repairs. Harness repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Coordinate with the vehicle OEM to repair or
replace the vehicle wiring.
Is the repair complete?
1. Turn OFF the ignition.
2. Install J 47279 Transmission Breakout to the
transmission 20-way connector. Leave the OEM
harness disconnected.
3. Using a DVOM, test for wire-to-wire shorts
between pin 10 and all other pins in the 20-way
connector.
4. Test for an open between pins 6 and 10.
Value(s)
Yes
Go to Step 12
No
Refer to Solenoid
Resistance Chart
(Appendix K)
Go to Step 8
Go to Step 11
Go to Step 8
Go to Step 10
NOTE: The resistance value between pins 10 and 6
will read normal solenoid resistance. The resistance
value between pins 10 and 4, between pins 10 and 5,
and between pins 10 and 9 will be twice normal
solenoid resistance. Refer to Solenoid Resistance
chart for these values.
8
9
10
11
12
Were any wiring defects found?
1. Remove the hydraulic control module assembly.
2. Disconnect SS1 from the internal harness.
3. Inspect the internal harness for wire-to-wire
shorts.
Were any wiring defects found?
Replace the internal wiring harness.
Is the replacement complete?
Replace SS1.
Is the replacement complete?
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
Refer to TCM diagnostic procedure, Section 3–6.
Is Section 3–6 complete?
In order to verify your repair:
1. Clear the DTC.
2. Drive the vehicle under normal operating
conditions.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Go to Step 12
Go to Step 12
Go to Step 12
Begin the
diagnosis again.
Go to Step 1
System OK
6–245
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0974 Shift Solenoid 1 (SS1) Control Circuit High
END VIEW OF
80-WAY CONNECTOR
END VIEW OF
20-WAY CONNECTOR
1
6
7
10
11
14
15
20
61
80
41
60
21
40
1
20
TRANSMISSION
HSD2
PCS1
PCS2
PCS3
SS1
TCM
WIRE 171
6
WIRE 136
4
WIRE 152
5
WIRE 133
9
10
WIRE 151
71
HSD2
V BATTERY
36
52
33
51
V09067.00.00
Circuit Description
Shift Solenoid 1 (SS1) is a normally closed (N/C) solenoid used to properly position the C1 and C2 logic latch
valves in forward ranges. The TCM commands the solenoid ON to supply control main pressure to the C1 and C2
logic latch valves. When SS1 is commanded OFF, control main pressure is relieved from the C1 and C2 latch
valves.
The TCM sends control current to SS1 from High Side Driver 2 (HSD2) via wire 171. HSD2 is continuously
ON unless the TCM detects a fault condition. The TCM energizes SS1 by switching the solenoid’s Low Side
Driver (LSD) ON. Wire 151 completes the circuit between SS1 and its LSD. DTC P0974 indicates that the TCM
has detected a short-to-battery condition in the low side of SS1 electrical circuit.
Conditions for Running the DTC
•
The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater
than 9V and less than 32V (24V TCM).
•
TCM initialization is in process or engine speed is greater than 200 rpm and less than 7500 rpm for 5 seconds.
Conditions for Setting the DTC
DTC P0974 is set when the TCM detects a short-to-battery in the SS1 return circuit for more than
125 milliseconds.
6–246
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0974 Shift Solenoid 1 (SS1) Control Circuit High
Actions Taken When the DTC Sets
When DTC P0974 is active, the following conditions will occur:
•
The CHECK TRANS light illuminates.
•
DTC is stored in TCM history.
•
Hydraulic default (SOL OFF) is commanded. The shift selector position and hydraulic state of latch valves
determines the range attained.
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
•
DTC P0974 indicates a short-to-battery in the electrical circuit for the SS1 solenoid.
•
You may have to drive the vehicle in order to experience a fault. Use the data obtained from failure records to
determine transmission range and/or certain vehicle operating variables such as temperature, run time etc. This
data can be useful in reproducing the failure mode when DTC was set.
•
Inspect the wiring for poor electrical connections at the TCM and transmission connector. Look for the
following conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
•
Inspect OEM wiring harness routing, look for possible contact points where chafing could occur leading to an
open or short circuit condition. Moving parts on the vehicle could be contacting the harness; this includes
parking brake drum, suspension components, etc.
•
When diagnosing for an intermittent short or open, massage the wiring harness while watching the test
equipment for a change.
•
Advanced Troubleshooting (requires a frequency-capable digital multimeter, if available)—measure solenoid
LSD functionality as follows:
1. Install TCM breakout harness adapter J 47275 between the 80-way connectors of the TCM and OEM
harness.
2. Set up a frequency-capable digital multimeter, e.g. Fluke 87, to monitor frequency by selecting the
VOLTS-DC scale and depressing the HERTZ button once.
3. Connect the RED test lead to the solenoid low side pin at TCM breakout harness adapter J 47275. Connect the BLACK test lead to the isolated ground pin.
4. Use Allison DOC™ For PC–Service Tool solenoid test function to command the solenoid ON and OFF.
5. Frequency should read in the KILOHERTZ range when the driver is commanded ON. Frequency should
read 0 hertz when the driver is commanded OFF. Note: A 1000 hertz test pulse may be present in the
SS1 solenoid circuit.
Copyright © 2005 General Motors Corp.
6–247
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
Test Description
This DTC requires the use of the J 47275 TCM Breakout and J 47279 Transmission Breakout. The numbers below
refer to step numbers on the diagnostic table.
2. This step tests for the proper ignition voltage.
3. This step tests for an active DTC.
4. This step tests for wire-to-wire shorts between wire 151 and other wires in the OEM chassis harness.
6. This step tests for the wire-to-wire shorts in the transmission internal harness.
DTC P0974 Shift Solenoid 1 (SS1) Control Circuit High
Step
1
2
3
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
1. Install the Allison DOC™ For PC–Service Tool. 9–18V (12V TCM)
18–32V (24V TCM)
2. Start the engine.
3. Record the failure records.
4. Monitor ignition voltage.
Is the voltage within the specified values?
1. Clear the DTC.
2. Start the engine and test drive the vehicle.
3. Attempt to duplicate the same conditions
observed in the failure records (range attained,
temperature, etc.)
Yes
Go to Step 2
Go to Step 3
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Resolve voltage
problem.
Go to Step 11
Go to Step 4
Go to
Diagnostic Aids
Go to Step 5
Go to Step 6
NOTE: This DTC is intended to detect a short-tobattery condition in the SS1 electrical circuit.
4
6–248
Did DTC P0974 return?
NOTE: Review Section 4—Wire Test Procedures
before performing steps.
1. Turn OFF the ignition.
2. Disconnect the TCM 80-way connector.
3. Install the OEM-side of the 80-way connector to
the J 47275 TCM Breakout. Leave the TCM
disconnected.
4. Disconnect the transmission 20-way connector.
5. Inspect the routing of wire 171 and wire 151 in
the chassis harness between the TCM and the
transmission connector.
6. At J 47275-1 TCM Overlay, test for wire-to-wire
shorts between pin 51 and all other pins in the
80-way connector.
Were any wire-to-wire shorts found?
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0974 Shift Solenoid 1 (SS1) Control Circuit High (cont’d)
Step
5
6
Action
NOTE: The vehicle OEM has responsibility for all
external wiring harness repairs. Harness repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Coordinate with the vehicle OEM to repair or
replace the vehicle wiring.
Is the repair complete?
1. Turn OFF the ignition.
2. Install J 47279 Transmission Breakout to the
transmission 20-way connector. Leave the OEM
harness disconnected.
3. Using DVOM, test for wire-to-wire shorts
between pin 10 and all other pins in the 20-way
connector.
Value(s)
Yes
Go to Step 11
No
Refer to Solenoid
Resistance Chart
(Appendix K)
Go to Step 7
Go to Step 10
Go to Step 8
Go to Step 9
NOTE: The resistance value between pins 10 and 6
will read normal solenoid resistance. The resistance
value between pins 10 and 4, between pins 10 and 5,
and between pins 10 and 9 will be twice normal
solenoid resistance. Refer to Solenoid Resistance
chart for these values.
7
8
9
10
11
Were any wire-to-wire shorts found?
1. Remove the hydraulic control module assembly.
2. Inspect the internal harness for wire-to-wire
shorts.
Were any wire-to-wire shorts found?
Repair or replace the internal wiring harness.
Is the repair complete?
Replace SS1.
Is the replacement complete?
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
Refer to TCM diagnostic procedure, Section 3–6.
Is Section 3–6 complete?
In order to verify your repair:
1. Clear the DTC.
2. Drive the vehicle under normal operating
conditions.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Go to Step 11
Go to Step 11
Go to Step 11
Begin the
diagnosis again.
Go to Step 1
System OK
6–249
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0975 Shift Solenoid 2 (SS2) Control Circuit Open
END VIEW OF
20-WAY CONNECTOR
END VIEW OF
80-WAY CONNECTOR
1
6
7
10
11
14
15
20
61
80
41
60
21
40
1
20
TRANSMISSION
HSD3
TCC
SS2
TCM
11
12
17
WIRE 131
WIRE 137
WIRE 119
(7-SPEED MODELS)
31
HSD3
V BATTERY
37
19
15
RTDR ACCUM
HSD3
SS2
B
A
WIRE 131
WIRE 119
RTDR OR
DIFF LOCK (T-CASE)
HSD3
PCS5
B
A
WIRE 131
WIRE 115
V09068.00.00
6–250
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
Circuit Description
• Shift Solenoid 2 (SS2) is a normally closed (N/C) solenoid used to either activate:
— The retarder accumulator air solenoid (retarder models)
— The C6 enable solenoid (7-speed models).
• The TCM commands the solenoid ON to supply control main pressure to SS2. When SS2 is commanded OFF,
the retarder accumulator air solenoid closes in retarder units or the C6 enable valve closes in 7-speed
transmissions.
• The TCM sends control current to SS2 from High Side Driver 3 (HSD3) via wire 131. HSD3 is continuously
ON unless the TCM detects a fault condition. The TCM energizes SS2 by switching the solenoid’s Low Side
Driver (LSD) ON. Wire 119 completes the circuit between SS2 and its LSD. DTC P0975 indicates that the
TCM has detected an open condition in SS2 electrical circuit. The open condition may exist in the high side
(wire 131) or low side (wire 119).
Conditions for Running the DTC
• The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater
than 9V and less than 32V (24V TCM).
•
TCM initialization is in process or engine speed is greater than 200 rpm and less than 7500 rpm for 5 seconds.
Conditions for Setting the DTC
DTC P0975 is set when the TCM detects an open circuit on the SS2 return circuit for more than 2 seconds.
Actions Taken When the DTC Sets
• When DTC P0975 is active, the following will occur:
— The CHECK TRANS light illuminates.
— DTC is stored in TCM history.
— For 7-speed transmissions, the TCM allows operation in second range through sixth range, and neutral and
reverse.
— For retarder equipped transmissions, the retarder accumulator is disabled.
Conditions for Clearing the DTC/CHECK TRANS light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
• DTC P0975 indicates an open in the electrical circuit for the SS2 solenoid. In addition to SS2, HSD3 also
supplies power to solenoids TCC and PCS5. If DTC P0975 is accompanied by DTC P2736 and P2761, the
open is most likely in the high side of the circuit.
• You may have to drive the vehicle in order to experience a fault. Use the data obtained from failure records to
determine transmission range and/or certain vehicle operating variables such as temperature, run time, etc. This
data can be useful in reproducing the failure mode when DTC was set.
• Inspect the wiring for poor electrical connections at the TCM and transmission connector. Look for the
following conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
Copyright © 2005 General Motors Corp.
6–251
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0975 Shift Solenoid 2 (SS2) Control Circuit Open
•
Inspect OEM wiring harness routing, look for possible contact points where chafing could occur leading to an
open or short circuit condition. Moving parts on the vehicle could be contacting the harness; this includes
parking brake drum, suspension components, etc.
•
When diagnosing for an intermittent short or open, massage the wiring harness while watching the test
equipment for a change.
Test Description
This DTC requires the use of the J 47275 TCM Breakout and J 47279 Transmission Breakout. The numbers below
refer to step numbers on the diagnostic table.
2. This step tests for the proper ignition voltage.
3. This step tests for an active DTC.
4. This step tests the OEM harness for an excessive voltage drop caused by an open condition in either wire
131 or wire 115 of the OEM chassis harness.
6. This step tests for an open condition in the transmission internal harness or retarder accumulator solenoid
harness.
7. This step tests for the proper SS2 resistance (7-speed models only).
DTC P0975 Shift Solenoid 2 (SS2) Control Circuit Open
Step
1
2
3
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
1. Install the Allison DOC™ For PC–Service Tool. 9–18V (12V TCM)
18–32V (24V TCM)
2. Start the engine.
3. Record the failure records.
4. Monitor ignition voltage.
Is the voltage within the specified values?
1. Clear the DTC.
2. Start the engine and test drive the vehicle.
3. Attempt to duplicate the same conditions
observed in the failure records (range attained,
temperature, etc.).
NOTE: This DTC is intended to detect an open
condition in the SS2 electrical circuit.
Did DTC P0975 return?
6–252
Copyright © 2005 General Motors Corp.
Yes
Go to Step 2
Go to Step 3
Go to Step 4
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Resolve voltage
problem.
Go to Step 11
Go to
Diagnostic Aids
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0975 Shift Solenoid 2 (SS2) Control Circuit Open (cont’d)
Step
4
Action
NOTE: Review Section 4—Wire Test Procedures
before performing steps.
1. Turn OFF the ignition.
2. Install the J 47275 TCM Breakout between the
OEM and TCM 80-way connector.
3. Install J 47279 Transmission Breakout between
the OEM and transmission 20-way connectors,
and OEM and retarder accumulator solenoid
connector, if applicable.
4. Turn ON the ignition, leave engine OFF.
5. Using Allison DOC™ For PC–Service Tool, enter
Solenoid Test mode and command SS2 ON.
6. Determine the voltage drop in the high side of the
SS2 circuit as follows:
• At J 47275-1 TCM Overlay, measure voltage
between pin 31 and an isolated ground.
• At J 47279-1 Transmission Overlay, measure
voltage between pin 11 (7-speed) or pin RTDR
ACCUM-B (retarder) and an isolated ground.
• Subtract the two voltage measurements to
obtain the voltage drop in the circuit.
7. Determine the voltage drop in the low side of the
SS2 circuit as follows:
• At J 47275-1 TCM Overlay, measure voltage
between pin 19 and an isolated ground.
• At J 47279-1 Transmission Overlay, measure
voltage between pin 17 (7-speed) or pin RTDR
ACCUM-A (retarder) and an isolated ground.
• Subtract the two voltage measurements to
obtain the voltage drop in the circuit.
Value(s)
Yes
Go to Step 5
No
Go to Step 6
NOTE: A voltage drop of more than 0.5V across
either circuit indicates an excessive voltage loss in
the OEM harness.
5
Did either high-side or low-side voltage drop exceed
0.5VDC?
NOTE: The vehicle OEM has responsibility for all
external wiring harness repairs. Harness repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Go to Step 11
Coordinate with the vehicle OEM to repair or
replace the vehicle wiring.
Is the repair complete?
Copyright © 2005 General Motors Corp.
6–253
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0975 Shift Solenoid 2 (SS2) Control Circuit Open (cont’d)
Step
6
7
8
9
10
11
6–254
Action
For 7-speed transmissions:
1. Turn OFF the ignition.
2. Disconnect the OEM 20-way connector from
J 47279 Transmission Breakout. Leave the
transmission-side connected.
3. Using a DVOM, measure the resistance between
pin 11 and pin 17 of the transmission 20-way
connector.
For retarder units:
1. Disconnect the retarder accumulator SS2
connector.
2. Using a DVOM, measure the resistance between
pins A and B of the retarder accumulator
solenoid.
Is the resistance within the specified value?
NOTE: This step applies to 7-speed models only.
For retarder models, go to Step 9.
1. Remove the hydraulic control module assembly.
2. Remove C6 Enable SS2.
3. Using a DVOM, measure resistance of SS2
between pins A and B.
Is the resistance within the specified value?
Replace the internal wiring harness.
Is the replacement complete?
Replace SS2.
Is the replacement complete?
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
Value(s)
Refer to Solenoid
Resistance Chart
(Appendix K)
Yes
Go to Step 10
No
7-speed
transmissions, go
to Step 7.
Retarder equipped
transmissions, go
to Step 9.
Refer to Solenoid
Resistance Chart
(Appendix K)
Go to Step 8
Go to Step 9
Refer to TCM diagnostic procedure, Section 3–6.
Is Section 3–6 complete?
In order to verify your repair:
1. Clear the DTC.
2. Drive the vehicle under normal operating
conditions.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Go to Step 11
Go to Step 11
Go to Step 11
Begin the
diagnosis again.
Go to Step 1
System OK
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0976 Shift Solenoid 2 (SS2) Control Circuit Low
END VIEW OF
20-WAY CONNECTOR
END VIEW OF
80-WAY CONNECTOR
1
6
7
10
11
14
15
20
61
80
41
60
21
40
1
20
TRANSMISSION
HSD3
TCC
SS2
TCM
11
12
17
WIRE 131
WIRE 137
WIRE 119
(7-SPEED MODELS)
31
HSD3
V BATTERY
37
19
15
RTDR ACCUM
HSD3
SS2
B
A
WIRE 131
WIRE 119
RTDR OR
DIFF LOCK (T-CASE)
HSD3
PCS5
B
A
WIRE 131
WIRE 115
V09068.00.00
Circuit Description
Shift Solenoid 2 (SS2) is a normally closed (N/C) solenoid used to either activate the retarder accumulator air
solenoid (retarder models) or the C6 enable solenoid (7-speed models).
The TCM sends control current to SS2 from High Side Driver 3 (HSD3) via wire 131. HSD3 is continuously
ON unless the TCM detects a fault condition. The TCM energizes SS2 by switching the solenoid’s Low Side
Driver (LSD) ON. Wire 119 completes the circuit between SS2 and its LSD. DTC P0976 indicates that the TCM
has detected a short-to-ground condition in the low side of SS2 electrical circuit.
Copyright © 2005 General Motors Corp.
6–255
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0976 Shift Solenoid 2 (SS2) Control Circuit Low
Conditions for Running the DTC
•
The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater
than 9V and less than 32V (24V TCM).
•
TCM initialization is in process or engine speed is greater than 200 rpm and less than 7500 rpm for 5 seconds.
Conditions for Setting the DTC
DTC P0976 is set when the TCM detects a short-to-ground in the SS2 return circuit for more than 125 milliseconds.
Actions Taken When the DTC Sets
When DTC P0976 is active, the following conditions will occur:
•
The CHECK TRANS light illuminates.
•
DTC is stored in TCM history.
•
The TCM allows operation in second range through sixth range and in Neutral and Reverse.
•
The TCM inhibits TCC operation.
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
•
DTC P0976 indicates a short-to-ground in the electrical circuit for the SS2 solenoid.
•
You may have to drive the vehicle in order to experience a fault. Use the data obtained from failure records to
determine transmission range and/or certain vehicle operating variables such as temperature, run time etc. This
data can be useful in reproducing the failure mode when DTC was set.
•
Inspect the wiring for poor electrical connections at the TCM and transmission connector. Look for the
following conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
•
Inspect OEM wiring harness routing, look for possible contact points where chafing could occur leading to an
open or short circuit condition. Moving parts on the vehicle could be contacting the harness; this includes
parking brake drum, suspension components, etc.
•
When diagnosing for an intermittent short or open, massage the wiring harness while watching the test
equipment for a change.
6–256
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
•
Advanced Troubleshooting (requires a frequency-capable digital multimeter, if available)—measure solenoid
LSD functionality as follows:
1. Install TCM breakout harness adapter J 47275 between the 80-way connectors of the TCM and OEM
harness.
2. Set up a frequency-capable digital multimeter, e.g. Fluke 87, to monitor frequency by selecting the
VOLTS-DC scale and depressing the HERTZ button once.
3. Connect the RED test lead to the solenoid low side pin at TCM breakout harness adapter J 47275. Connect the BLACK test lead to the isolated ground pin.
4. Use Allison DOC™ For PC–Service Tool solenoid test function to command the solenoid ON and OFF.
5. Frequency should read in the KILOHERTZ range when the driver is commanded ON. Frequency should
read 0 hertz when the driver is commanded OFF.
Test Description
This DTC requires the use of the J 47275 TCM Breakout and J 47279 Transmission Breakout. The numbers below
refer to step numbers on the diagnostic table.
2.
3.
4.
6.
This step tests for the proper ignition voltage.
This step tests for an active DTC.
This step tests for wire-to-wire shorts or a short-to-ground condition in wire 119.
This step tests for the wire-to-wire shorts or a short-to-ground in the internal transmission harness.
DTC P0976 Shift Solenoid 2 (SS2) Control Circuit Low
Step
1
2
3
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
1. Install the Allison DOC™ For PC–Service Tool. 9–18V (12V TCM)
18–32V (24V TCM)
2. Start the engine.
3. Record the failure records.
4. Monitor ignition voltage.
Is the voltage within the specified values?
1. Clear the DTC.
2. Start the engine and test drive the vehicle.
3. Attempt to duplicate the same conditions
observed in the failure records (range attained,
temperature, etc.).
Yes
Go to Step 2
Go to Step 3
Go to Step 4
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Resolve voltage
problem.
Go to Step 11
Go to
Diagnostic Aids
NOTE: This DTC is intended to detect a short-toground condition in the SS2 electrical circuit.
Did DTC P0976 return?
Copyright © 2005 General Motors Corp.
6–257
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0976 Shift Solenoid 2 (SS2) Control Circuit Low (cont’d)
Step
4
5
Action
NOTE: Review Section 4—Wire Test Procedures
before performing steps.
1. Turn OFF the ignition.
2. Disconnect the TCM 80-way connector.
3. Install the OEM-side of the 80-way connector to
the J 47275 TCM Breakout. Leave the TCM
disconnected.
4. Disconnect the transmission 20-way connector.
5. Inspect the routing of wire 119 in the chassis
harness between the TCM and the transmission
connector.
6. At J 47275-1 TCM Overlay, test for wire-to-wire
shorts between pin 19 and all other pins in the
80-way connector, and shorts-to-ground between
pin 19 and chassis ground.
Were any wire-to-wire shorts or shorts-to-ground
wiring defects found?
NOTE: The vehicle OEM has responsibility for all
external wiring harness repairs. Harness repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Value(s)
Coordinate with the vehicle OEM to repair or
replace the vehicle wiring.
Is the repair complete?
6–258
Copyright © 2005 General Motors Corp.
Yes
Go to Step 5
Go to Step 11
No
Go to Step 6
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0976 Shift Solenoid 2 (SS2) Control Circuit Low (cont’d)
Step
6
Action
For 7-speed transmissions:
1. Turn OFF the ignition.
2. Install J 47279 Transmission Breakout to the
transmission 20-way connector. Leave the OEM
harness disconnected.
3. Using a DVOM, test for wire-to-wire shorts
between pin 17 and all other pins in the 20-way
connector.
Value(s)
Yes
7-speed
transmissions go to
Step 7.
Retarder equipped
transmission go to
Step 9.
No
Go to Step 10
Go to Step 8
Go to Step 9
NOTE: The resistance value between pins 17 and
11 will read normal solenoid resistance. The
resistance value between 17 and 12 will be twice
normal solenoid resistance. Refer to Solenoid
Resistance chart for these values.
4. Test for shorts-to-ground between pin 17 and
chassis ground.
For retarder units:
1. Turn OFF the ignition.
2. Disconnect the retarder accumulator solenoid.
3. Using a DVOM, test for shorts-to-ground
between pin A of SS2 and chassis ground.
NOTE: The resistance value of SS2 (retarder
accumulator) will be normal solenoid resistance.
Refer to Solenoid Resistance chart for these values.
7
8
9
10
11
Were any wire-to-wire shorts or shorts-to-ground
found?
NOTE: This step applies to 7-speed models only.
For retarder models skip to Step 9.
1. Remove the hydraulic control module assembly.
2. Inspect the internal harness for wire-to-wire
shorts or shorts-to-ground.
Were any wire-to-wire or shorts-to-ground found?
Repair or replace the internal wiring harness.
Is the repair complete?
Replace SS2.
Is the replacement complete?
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
Refer to TCM diagnostic procedure, Section 3–6.
Is Section 3–6 complete?
In order to verify your repair:
1. Clear the DTC.
2. Drive the vehicle under normal operating
conditions.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Go to Step 11
Go to Step 11
Go to Step 11
Begin the
diagnosis again.
Go to Step 1
System OK
6–259
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0977 Shift Solenoid 2 (SS2) Control Circuit High
END VIEW OF
20-WAY CONNECTOR
END VIEW OF
80-WAY CONNECTOR
1
6
7
10
11
14
15
20
61
80
41
60
21
40
1
20
TRANSMISSION
HSD3
TCC
SS2
TCM
11
12
17
WIRE 131
WIRE 137
WIRE 119
(7-SPEED MODELS)
31
HSD3
V BATTERY
37
19
15
RTDR ACCUM
HSD3
SS2
B
A
WIRE 131
WIRE 119
RTDR OR
DIFF LOCK (T-CASE)
HSD3
PCS5
B
A
WIRE 131
WIRE 115
V09068.00.00
Circuit Description
Shift Solenoid 2 (SS2) is a normally closed (N/C) solenoid used to either activate the retarder accumulator air
solenoid (retarder models) or the C6 enable solenoid (7-speed models). The TCM commands the solenoid ON to
supply control main pressure to SS2. When SS2 is commanded OFF, the retarder accumulator air solenoid closes in
retarder units or the C6 enable valve closes in 7-speed transmissions.
The TCM sends control current to SS2 from High Side Driver 3 (HSD3) via wire 131. HSD3 is continuously
ON unless the TCM detects a fault condition. The TCM energizes SS2 by switching the solenoid’s Low Side
Driver (LSD) ON. Wire 119 completes the circuit between SS2 and its LSD. DTC P0977 indicates that the TCM
has detected a short-to-battery condition in the low side of SS2 electrical circuit.
6–260
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0977 Shift Solenoid 2 (SS2) Control Circuit High
Conditions for Running the DTC
• The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater
than 9V and less than 32V (24V TCM).
•
TCM initialization is in process or engine speed is greater than 200 rpm and less than 7500 rpm for 5 seconds.
Conditions for Setting the DTC
DTC P0977 is set when the TCM detects a short-to-battery in the SS2 return circuit for more than
125 milliseconds.
Actions Taken When the DTC Sets
When DTC P0977 is active, the following conditions will occur:
•
The CHECK TRANS light illuminates.
•
DTC is stored in TCM history.
•
The TCM allows operation in second range through sixth range and in Neutral and Reverse.
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
• DTC P0977 indicates a short-to-battery in the electrical circuit for the SS2 solenoid.
•
You may have to drive the vehicle in order to experience a fault. Use the data obtained from failure records to
determine transmission range and/or certain vehicle operating variables such as temperature, run time etc. This
data can be useful in reproducing the failure mode when DTC was set.
•
Inspect the wiring for poor electrical connections at the TCM and transmission connector. Look for the
following conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
Inspect OEM wiring harness routing, look for possible contact points where chafing could occur leading to an
open or short circuit condition. Moving parts on the vehicle could be contacting the harness; this includes
parking brake drum, suspension components, etc.
•
•
When diagnosing for an intermittent short or open, massage the wiring harness while watching the test
equipment for a change.
•
Advanced Troubleshooting (requires a frequency-capable digital multimeter, if available)—measure solenoid
LSD functionality as follows:
1. Install TCM breakout harness adapter J 47275 between the 80-way connectors of the TCM and OEM
harness.
2. Set up a frequency-capable digital multimeter, e.g. Fluke 87, to monitor frequency by selecting the
VOLTS-DC scale and depressing the HERTZ button once.
Copyright © 2005 General Motors Corp.
6–261
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
3. Connect the RED test lead to the solenoid low side pin at TCM breakout harness adapter J 47275.
Connect the BLACK test lead to the isolated ground pin.
4. Use Allison DOC™ For PC–Service Tool solenoid test function to command the solenoid ON and OFF.
5. Frequency should read in the KILOHERTZ range when the driver is commanded ON. Frequency should
read 0 hertz when the driver is commanded OFF.
Test Description
This DTC requires the use of the J 47275 TCM Breakout and J 47279 Transmission Breakout. The numbers below
refer to step numbers on the diagnostic table.
2. This step tests for the proper ignition voltage.
3. This step tests for an active DTC.
4. This step tests for wire-to-wire shorts between wire 119 and other wires in the OEM chassis harness.
6. This step tests for the wire-to-wire shorts in the transmission internal harness.
10. This step tests for proper operation of the SS2 Low Side Driver.
DTC P0977 Shift Solenoid 2 (SS2) Control Circuit High
Step
1
2
3
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
1. Install the Allison DOC™ For PC–Service Tool. 9–18V (12V TCM)
18–32V (24V TCM)
2. Start the engine.
3. Record the failure records.
4. Monitor ignition voltage.
Is the voltage within the specified values?
1. Clear the DTC.
2. Start the engine and test drive the vehicle.
3. Attempt to duplicate the same conditions
observed in the failure records (range attained,
temperature, etc.).
NOTE: This DTC is intended to detect a short-tobattery condition in the SS2 electrical circuit.
Did DTC P0977 return?
6–262
Copyright © 2005 General Motors Corp.
Yes
Go to Step 2
Go to Step 3
Go to Step 4
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Resolve voltage
problem.
Go to Step 11
Go to
Diagnostic Aids
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0977 Shift Solenoid 2 (SS2) Control Circuit High (cont’d)
Step
4
5
6
Action
NOTE: Review Section 4—Wire Test Procedures
before performing steps.
1. Turn OFF the ignition.
2. Disconnect the TCM 80-way connector.
3. Install the OEM-side of the 80-way connector to
the J 47275 TCM Breakout. Leave the TCM
disconnected.
4. Disconnect the transmission 20-way connector.
5. Inspect the routing of wires 131 and 119 in the
chassis harness between the TCM and the
transmission connector.
6. At J 47275-1 TCM Overlay, test for wire-to-wire
shorts between pin 19 and all other pins in the
80-way connector.
Were any wire-to-wire shorts found?
NOTE: The vehicle OEM has responsibility for all
external wiring harness repairs. Harness repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Value(s)
Coordinate with the vehicle OEM to repair or
replace the vehicle wiring.
Is the repair complete?
For 7-speed transmissions:
1. Turn OFF the ignition.
2. Install J 47279 Transmission Breakout to the
transmission 20-way connector. Leave the OEM
harness disconnected.
3. Using a digital multimeter (DVOM), test for
wire-to-wire shorts between pin 17 and all other
pins in the 20-way connector.
Yes
Go to Step 5
No
Go to Step 6
Go to Step 11
7-speed
transmissions go to
Step 7.
Retarder equipped
transmission go to
Step 9.
Go to Step 10
NOTE: The resistance value between pins 17 and
11 will read normal solenoid resistance. The
resistance value between pins 17 and 12 will be
twice normal solenoid resistance. Refer to Solenoid
Resistance chart for these values.
For retarder equipped units:
1. Turn OFF the ignition.
2. Disconnect the retarder accumulator solenoid.
3. Using a digital multimeter (DVOM), test for
wire-to-wire shorts between pin A and pin B of
SS2.
NOTE: The resistance value between pins A and B
of SS2 (retarder accumulator) will be normal
solenoid resistance. Refer to Solenoid Resistance
chart for this value.
Were any wire-to-wire shorts found?
Copyright © 2005 General Motors Corp.
6–263
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0977 Shift Solenoid 2 (SS2) Control Circuit High (cont’d)
Step
7
8
9
10
11
6–264
Action
NOTE: This step applies to 7-speed models only.
Retarder models skip to Step 9.
1. Remove the hydraulic control module assembly.
2. Inspect the internal harness for wire-to-wire
shorts.
Were any wire-to-wire shorts found?
Repair or replace the internal wiring harness.
Is the repair complete?
Replace SS2.
Is the replacement complete?
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
Value(s)
Refer to TCM diagnostic procedure, Section 3–6.
Is Section 3–6 complete?
In order to verify your repair:
1. Clear the DTC.
2. Drive the vehicle under normal operating
conditions.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 8
No
Go to Step 9
Go to Step 11
Go to Step 11
Go to Step 11
Begin the
diagnosis again.
Go to Step 1
System OK
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0989 Retarder Pressure Sensor Failed Low
END VIEW OF
20-WAY CONNECTOR
END VIEW OF
80-WAY CONNECTOR
1
6
7
10
11
14
15
20
61
80
41
60
21
40
1
20
TO RETARDER
CONTROL DEVICES
RETARDER
REQUEST SENSOR
(RESISTANCE
MODULE)
A
PWM
THROTTLE
SOURCE
B
C
TCM
THROTTLE
POSITION
SENSOR (TPS)
OR
ELECTRONIC
BRAKING (EBS)
RTDR PRESSURE
SENSOR
WIRE 156
WIRE 112
C
WIRE 144
B
WIRE 158
A
RETARDER TEMP
ENGINE TEMP
TRANSMISSION
ANALOG RETURN
OIL LEVEL
HALL
A
C
EFFECT
B
SUMP TEMP
19
16
15
18
PS1
NC*
* NORMALLY
3
WIRE 175
WIRE 135
56
RETARDER REQUEST SIGNAL
12
5V SENSOR VOLTAGE
44
THROTTLE POSITION OR
RTDR PRESSURE SIGNAL
58
ANALOG RETURN
75
RETARDER TEMP
35
ENGINE WATER TEMP
16
OIL LEVEL SENSOR
54
SUMP TEMP
77
PS1 DIAGNOSTIC
PRESSURE SWITCH
WIRE 158
WIRE 112
WIRE 116
WIRE 154
WIRE 177
CLOSED
V09069.01.00
Copyright © 2005 General Motors Corp.
6–265
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0989 Retarder Pressure Sensor Failed Low
Circuit Description
The Transmission Control Module (TCM) can be calibrated to control retarder capacity in response to signals from
an integral vehicle electronic braking system (EBS). However, the EBS controller requires accurate information
about the state of the retarder. Because retarder capacity is proportional to retarder charge pressure, the TCM uses
a pressure transducer located in the retarder cavity to measure the precise retarder capacity when the retarder is in
operation. The TCM is connected to the pressure transducer by:
•
a reference voltage wire,
•
retarder request signal wire, and
•
analog ground wire.
When the TCM commands more retardation, pressure in the retarder charge pressure circuit increases resulting in a
larger voltage signal from the retarder pressure transducer.
Conditions for Running the DTC
•
The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater
than 9V and less than 32V (24V TCM).
•
Engine speed is greater than 200 rpm and less than 7500 rpm for 5 seconds.
•
Electronic Braking is enabled in the TCM calibration.
Conditions for Setting the DTC
The TCM detects retarder pressure voltage signal equal to 0V for 10 seconds.
Actions Taken When the DTC Sets
When DTC P0989 is active, the following conditions will occur:
•
The TCM does not illuminate the CHECK TRANS light.
•
DTC is stored in TCM history.
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
•
Inspect the wiring for poor electrical connections at the TCM and retarder pressure sensor. Look for the
following conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
•
When diagnosing for an intermittent short or open, massage the wiring harness while watching the test
equipment for a change.
•
You may have to drive the vehicle and operate the retarder in order to experience a fault.
6–266
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
•
DTC P0989 can be caused by an open or short-to-ground in either the 5V reference wire 112 or retarder
pressure sensor signal wire 144. The retarder pressure sensor shares a common 5V reference voltage wire 112
with the optional transmission oil level sensor (OLS) and retarder request sensor. An open or short-to-ground
in the common 5V reference causes a “sensor failed low” code for the other devices as well. An open or shortto-ground on wire 144 will cause DTC P0989 only.
Test Description
This DTC requires the use of the J 47275 TCM Breakout. The numbers below refer to step numbers on the
diagnostic table.
2. This step tests for active diagnostic codes.
3. This step tests for wire-to-wire shorts, opens, or shorts-to-ground on wires 112 and 144.
6. This step verifies the TCM is supplying proper 5V reference voltage.
DTC P0989 Retarder Pressure Sensor Failed Low
Step
1
2
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
1.
2.
3.
4.
Value(s)
Install the Allison DOC™ For PC–Service Tool.
Start the engine.
Record the failure records.
Clear the DTC. Attempt to duplicate same
operating conditions observed in failure records.
Yes
Go to Step 2
Go to Step 3
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Go to
Diagnostic Aids
NOTE: This DTC indicates that the retarder
pressure sensor signal is at 0V for 10 seconds. It
may also indicate an open or short-to-ground in
either the 5V reference wire 112 or retarder
pressure sensor signal wire 144.
3
Did DTC P0989 return?
1. Turn OFF the ignition.
2. Inspect the routing of the 5V reference wire 112,
signal wire 144, and analog return wire 158
between the TCM and the retarder pressure
sensor.
3. Disconnect the 80-way connector from the TCM.
4. Install the OEM-side of the 80-way connector to
J 47275 TCM Breakout. Leave the TCM
disconnected.
5. Disconnect the retarder pressure sensor from the
OEM wiring harness.
6. Disconnect the transmission 20-way connector
and RMR connector, if installed.
7. Test for wire-to-wire shorts, opens and shorts-toground on wires 112 and 144.
Was chafing or wire damage found?
Copyright © 2005 General Motors Corp.
Go to Step 4
Go to Step 5
6–267
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0989 Retarder Pressure Sensor Failed Low (cont’d)
Step
4
5
6
7
8
6–268
Action
NOTE: The vehicle OEM has responsibility for all
external wiring harness repairs. Harness repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Coordinate with the vehicle OEM to repair or
replace the vehicle wiring.
Is the repair complete?
1. Remove J 47275 TCM Breakout and reconnect
the TCM and OEM 80-way connector to each
other.
2. Disconnect the retarder pressure sensor from the
OEM harness, if not disconnected in Step 3
above.
3. Reconnect the transmission 20-way connector
and RMR connector, if installed.
4. Turn ON the ignition. Leave the engine OFF.
5. Using a DVOM, measure the voltage between
pin B (5V reference wire 112) and pin A (analog
return wire 158) at the OEM harness retarder
pressure sensor connector.
Is the voltage within the specified values?
Replace the retarder pressure sensor.
Is the replacement complete
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
Value(s)
Yes
Go to Step 8
No
4.75–5.0V
Go to Step 6
Go to Step 7
Refer to TCM diagnostic procedure, Section 3–6.
Is Section 3–6 complete?
In order to verify your repair:
1. Clear the DTC.
2. Drive the vehicle under normal operating
conditions.
3. Using Allison DOC™ For PC–Service Tool,
monitor retarder pressure.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Go to Step 8
Go to Step 8
Begin the
diagnosis again.
Go to Step 1
System OK
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0990 Retarder Pressure Sensor Failed High
END VIEW OF
20-WAY CONNECTOR
END VIEW OF
80-WAY CONNECTOR
1
6
7
10
11
14
15
20
61
80
41
60
21
40
1
20
TO RETARDER
CONTROL DEVICES
RETARDER
REQUEST SENSOR
(RESISTANCE
MODULE)
A
PWM
THROTTLE
SOURCE
B
C
TCM
THROTTLE
POSITION
SENSOR (TPS)
OR
ELECTRONIC
BRAKING (EBS)
RTDR PRESSURE
SENSOR
WIRE 156
WIRE 112
C
WIRE 144
B
WIRE 158
A
RETARDER TEMP
ENGINE TEMP
TRANSMISSION
ANALOG RETURN
OIL LEVEL
HALL
A
C
EFFECT
B
SUMP TEMP
19
16
15
18
PS1
NC*
* NORMALLY
3
WIRE 175
WIRE 135
56
RETARDER REQUEST SIGNAL
12
5V SENSOR VOLTAGE
44
THROTTLE POSITION OR
RTDR PRESSURE SIGNAL
58
ANALOG RETURN
75
RETARDER TEMP
35
ENGINE WATER TEMP
16
OIL LEVEL SENSOR
54
SUMP TEMP
77
PS1 DIAGNOSTIC
PRESSURE SWITCH
WIRE 158
WIRE 112
WIRE 116
WIRE 154
WIRE 177
CLOSED
V09069.01.00
Copyright © 2005 General Motors Corp.
6–269
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0990 Retarder Pressure Sensor Failed High
Circuit Description
The Transmission Control Module (TCM) can be calibrated to control retarder capacity in response to signals from
an integral vehicle electronic braking system (EBS). However, the EBS controller requires accurate information
about the state of the retarder. Because retarder capacity is proportional to retarder charge pressure, the TCM uses
a pressure transducer located in the retarder cavity to measure the precise retarder capacity when the retarder is in
operation. The TCM is connected to the pressure transducer by:
•
a reference voltage wire,
•
retarder pressure signal wire, and
•
analog ground wire.
When the TCM commands more retardation, pressure in the retarder charge pressure circuit increases resulting in a
larger voltage signal from the retarder pressure transducer.
Conditions for Running the DTC
•
The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater
than 9V and less than 32V (24V TCM).
•
Engine speed is greater than 200 rpm and less than 7500 rpm for 5 seconds.
•
Electronic Braking is enabled in the TCM calibration.
Conditions for Setting the DTC
The TCM detects retarder pressure voltage signal greater than or equal to 5V for 10 seconds.
Actions Taken When the DTC Sets
When DTC P0990 is active, the following conditions will occur:
•
The TCM does not illuminate the CHECK TRANS light.
•
DTC is stored in TCM history.
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
•
Inspect the wiring for poor electrical connections at the TCM and retarder pressure sensor. Look for the
following conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
•
When diagnosing for an intermittent short or open, massage the wiring harness while watching the test
equipment for a change.
•
You may have to drive the vehicle and operate the retarder in order to experience a fault.
6–270
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
•
DTC P0990 can be caused by a short-to-battery in the 5V reference wire 112 or retarder pressure sensor
wire 144. DTC P0990 can also be caused by an open in analog return wire 158. The retarder pressure sensor
shares a common 5V reference voltage wire 112 with the optional transmission oil level sensor (OLS) and
retarder request sensor. A short-to-battery in the 5V reference wire 112 or open in analog return wire 158
causes a “sensor failed high” code for these other devices as well. A short-to-battery in retarder pressure sensor
signal wire 144 will produce DTC P0990 only.
Test Description
This DTC requires the use of the J 47275 TCM Breakout. The numbers below refer to step numbers on the
diagnostic table.
2. This step tests for active diagnostic codes.
3. This step tests for wire-to-wire shorts or shorts-to-battery on wires 112 and 144, and opens in wire 158.
6. This step verifies the TCM is supplying proper 5V reference voltage.
DTC P0990 Retarder Pressure Sensor Failed High
Step
1
2
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
1.
2.
3.
4.
Value(s)
Install the Allison DOC™ For PC–Service Tool.
Start the engine.
Record the failure records.
Clear the DTC. Attempt to duplicate same
operating conditions observed in failure records.
Yes
Go to Step 2
Go to Step 3
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Go to
Diagnostic Aids
NOTE: This DTC indicates that the retarder
pressure sensor signal is greater than or equal to 5V
for 10 seconds. It may also indicate a short-tobattery in either the 5V reference wire 112 or
retarder pressure sensor signal wire 144, or an open
in analog return wire 158.
3
Did DTC P0990 return?
1. Turn OFF the ignition.
2. Inspect the routing of the 5V reference wire 112,
signal wire 144, and analog return wire 158
between the TCM and the retarder pressure
sensor.
3. Disconnect the 80-way connector from the TCM.
4. Install the OEM-side of the 80-way connector to
J 47275 TCM Breakout. Leave the TCM-side
disconnected.
5. Disconnect the retarder pressure sensor from the
OEM wiring harness.
6. Disconnect the transmission 20-way connector
and RMR connector, if installed.
7. Test for wire-to-wire shorts and shorts-to-battery
in wires 112 and 144.
8. Test for an open condition in wire 158.
Was chafing or wire damage found?
Copyright © 2005 General Motors Corp.
Go to Step 4
Go to Step 5
6–271
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P0990 Retarder Pressure Sensor Failed High (cont’d)
Step
4
5
6
7
8
6–272
Action
NOTE: The vehicle OEM has responsibility for all
external wiring harness repairs. Harness repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Coordinate with the vehicle OEM to repair or
replace the vehicle wiring.
Is the repair complete?
1. Remove J 47275 TCM Breakout and reconnect
the TCM and OEM 80-way connectors to each
other.
2. Disconnect the retarder pressure sensor from the
OEM harness, if not disconnected in Step 3.
3. Reconnect the transmission 20-way connector
and RMR connector, if installed.
4. Turn ON the ignition.
5. Using a DVOM, measure the voltage between
pin B (5V reference wire 112) and pin A (analog
return wire 158) at the OEM harness retarder
pressure sensor connector.
Is the voltage within the specified values?
Replace the retarder pressure sensor.
Is the replacement complete?
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
Value(s)
Yes
Go to Step 8
No
4.75–5.0V
Go to Step 6
Go to Step 7
Refer to TCM diagnostic procedure, Section 3–6.
Is Section 3–6 complete?
In order to verify your repair:
1. Clear the DTC.
2. Drive the vehicle under normal operating
conditions.
3. Using Allison DOC™ For PC–Service Tool,
monitor retarder pressure.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Go to Step 8
Go to Step 8
Begin the
diagnosis again.
Go to Step 1
System OK
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P1739 Incorrect Low Gear Ratio
Refer to Low Range Hydraulic Schematic
Circuit Description
The Transmission Control Module (TCM) uses input from the turbine speed and the output speed sensors to
determine the current commanded steady state gear ratio. The TCM then compares the known gear ratio to the
calculated gear ratio for the current range.
Conditions for Running the DTC
•
Hydraulic system is pressurized.
•
No shift in progress.
•
Hydraulic default condition not present.
•
Output speed is above 200 rpm.
•
Engine initialization or shutdown is not in progress.
Conditions for Setting the DTC
DTC P1739 sets when the calculated low range ratio (steady state) differs from the known Low range ratio.
Actions Taken When the DTC Sets
When DTC P1739 is active, the following conditions will occur:
•
The TCM commands second range and allows operation in second range through sixth range, and in neutral
and reverse.
•
The CHECK TRANS light illuminates.
•
DTC is stored in TCM history.
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
•
You may have to clear the DTC and drive the vehicle in order to experience a fault. Use the data obtained from
failure records to determine transmission range and/or certain vehicle operating variables such as temperature,
run time, etc. This data can be useful in reproducing failures mode where DTC was set.
•
Incorrect ratio codes typically indicate mechanical problems with specific clutches for range indicated, i.e. C3
and C6 (3000 7-speed model) or C1 and C6 (4000 7-speed model) for Low range.
•
An incorrect ratio DTC may indicate a mechanically failed clutch control solenoid. Check the DTC
information for the specific solenoid.
•
Output speed or turbine speed tone wheel damage may cause erratic speed sensor input allowing this code to set.
Copyright © 2005 General Motors Corp.
6–273
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
Test Description
The numbers below refer to step numbers on the diagnostic table.
2. This step tests for proper transmission fluid level.
3. This step tests for proper ignition voltage.
4. This step tests for proper match between calibration gear ratio and actual gear ratio.
5. This step tests speed sensor readings.
6. This step tests for clutch slippage in Low range.
7. This step tests for clutch pressure to range clutches.
8. This step tests for evidence of clutch failure.
DTC P1739 Incorrect Low Gear Ratio
Step
1
2
3
4
6–274
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
Yes
Go to Step 2
Perform the Fluid Checking Procedure (refer to
Go to Step 3
appropriate mechanic’s tips).
Is the transmission fluid level correct?
1. Start the engine.
9–18V (12V TCM)
Go to Step 4
18–32V (24V TCM)
2. Record the DTC Failure Record data.
3. Using the Allison DOC™ For PC–Service Tool,
measure ignition voltage.
Is the voltage within the specified value?
1. Start the engine and drive the vehicle under
Watch for erratic Go to appropriate
normal operating conditions.
speed sensor DTC
speed sensor
2. Using Allison DOC™ For PC–Service Tool,
signals
monitor turbine, engine, and output speed sensor
readings.
Is speed sensor data erratic or are dropouts in signal
indicated?
Copyright © 2005 General Motors Corp.
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Go to Fluid Check
Procedure (refer to
mechanic’s tips)
Go to General
Troubleshooting
Section 8
Go to Step 5
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P1739 Incorrect Low Gear Ratio (cont’d)
Step
5
Action
Value(s)
Yes
Go to
Diagnostic Aids
No
Go to Step 6
Refer to Main
Clutch Pressure
specifications in
Appendix B
Go to Step 7
Go to Step 8
Go to Step 10
Go to
Diagnostic Aids
Go to Step 11
Go to Step 9
WARNING: To help avoid injury or property
damage caused by sudden and unexpected
vehicle movement, do not start a stationary
stall test until you do all of the following:
• Put the transmission in N (Neutral).
• Apply the parking brake and service brake.
• Chock the wheels and take any other steps
necessary to prevent the vehicle from
moving.
• Warn personnel to keep clear of the vehicle
and its path.
CAUTION: DO NOT conduct a stall test in
Low. The torque produced in Low can damage
the vehicle driveline or axle.
6
7
8
1. Turn OFF the ignition.
2. Install 2000 kPa (300 psi) pressure gauges in
main pressure tap, and C3 and C6 (3000 7-speed
only) or C1 and C6 (4000 7-speed only) pressure
taps.
3. Start the engine.
4. Using Allison DOC™ For PC–Service Tool,
select the clutch test mode.
5. With brakes applied, select D (Drive).
6. With the engine at idle speed, select and attain the
range indicated by the DTC. Turbine speed
should go to zero.
Did turbine speed remain at zero?
Read and record Main, C6, C1 (4000 7-speed only)
or C3 (3000 7-speed only) clutch pressures.
Are the pressure readings within specified values in
Appendix B?
Remove the dipstick and inspect the transmission
fluid for clutch debris or burnt odor. If necessary,
drain a small amount of fluid for this inspection.
Are there signs of a clutch failure?
1. Consult the appropriate service manual and
remove the transmission hydraulic control
module.
2. Inspect the control valve bodies for stuck or
sticking solenoid regulator valves and logic latch
valves.
3. Inspect the suction filter. Ensure screen is not
plugged.
4. Inspect for damaged gaskets and face seals.
Was a valve body problem found and repaired?
Copyright © 2005 General Motors Corp.
6–275
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P1739 Incorrect Low Gear Ratio (cont’d)
Step
9
10
11
6–276
Action
Using pressure readings obtained in Step 6 above,
replace the affected solenoid.
• Incorrect C1 (4000 7-speed only) pressure—
PCS1
• Incorrect C3 (3000 7-speed only) pressure—
PCS3
• Incorrect C6 (Both) pressure—PCS6
Value(s)
Is the replacement complete?
Remove the main and lube filters and inspect for
clutch debris. It may also be necessary to remove the
control module and inspect the suction screen for
clutch debris.
If debris is found, remove the transmission for
overhaul or replacement (refer to the appropriate
service manual).
Is the replacement complete?
In order to verify your repair:
1. Clear the DTC.
2. Using Allison DOC™ For PC–Service Tool,
monitor engine, turbine and output speed sensor
readings.
3. Drive the vehicle under normal operating
conditions.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 11
No
Go to Step 11
Begin the
diagnosis again.
Go to Step 1
System OK
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P1891 Throttle Position Sensor PWM Signal Low Input
END VIEW OF
20-WAY CONNECTOR
END VIEW OF
80-WAY CONNECTOR
1
6
7
10
11
14
15
20
61
80
41
60
21
40
1
20
TO RETARDER
CONTROL DEVICES
RETARDER
REQUEST SENSOR
(RESISTANCE
MODULE)
A
PWM
THROTTLE
SOURCE
B
C
TCM
THROTTLE
POSITION
SENSOR (TPS)
OR
ELECTRONIC
BRAKING (EBS)
RTDR PRESSURE
SENSOR
WIRE 156
WIRE 112
C
WIRE 144
B
WIRE 158
A
RETARDER TEMP
ENGINE TEMP
TRANSMISSION
ANALOG RETURN
OIL LEVEL
HALL
A
C
EFFECT
B
SUMP TEMP
19
16
15
18
PS1
NC*
* NORMALLY
3
WIRE 175
WIRE 135
56
RETARDER REQUEST SIGNAL
12
5V SENSOR VOLTAGE
44
THROTTLE POSITION OR
RTDR PRESSURE SIGNAL
58
ANALOG RETURN
75
RETARDER TEMP
35
ENGINE WATER TEMP
16
OIL LEVEL SENSOR
54
SUMP TEMP
77
PS1 DIAGNOSTIC
PRESSURE SWITCH
WIRE 158
WIRE 112
WIRE 116
WIRE 154
WIRE 177
CLOSED
V09069.01.00
Copyright © 2005 General Motors Corp.
6–277
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P1891 Throttle Position Sensor PWM Signal Low Input
Circuit Description
The Transmission Control Module (TCM) can be calibrated to receive throttle information from a Pulse Width
Modulation (PWM) signal.
Conditions for Running the DTC
•
The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater
than 9V and less than 32V (24V TCM).
•
Engine speed is greater than 200 rpm and less than 7500 rpm for 5 seconds.
•
The TCM has autodetected a PWM throttle source.
Conditions for Setting the DTC
The TCM detects PWM throttle signal less than 4.9 percent for 5 seconds.
Actions Taken When the DTC Sets
When DTC P1891 is active, the following conditions will occur:
•
The TCM does not illuminate the CHECK TRANS light.
•
DTC is stored in TCM history.
•
TCM uses default throttle values.
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
•
•
The TCM detects the throttle source automatically during the initial series of engine starts. The TCM may have
auto-detected the wrong throttle source type. Use the Allison DOC™ For PC–Service Tool to reset auto-detect
or select the appropriate throttle source if PWM-type sensor is not being used.
Inspect the wiring for poor electrical connections at the TCM and PWM throttle sensor. Look for the following
conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
•
When diagnosing for an intermittent short or open, massage the wiring harness while watching the test
equipment for a change.
•
You may have to drive the vehicle in order to experience a fault.
•
Advanced troubleshooting—monitor frequency on pin 44 as throttle is increased from closed throttle to wide
open throttle. If frequency does not vary, the signal is bad. Have the vehicle manufacturer replace the PWM
device.
6–278
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
Test Description
This DTC requires the use of the J 47275 TCM Breakout. The numbers below refer to step numbers on the
diagnostic table.
2. This step tests for proper ignition voltage.
3. This step tests for operation of the PWM throttle sensor.
4. This step tests for wire-to-wire shorts, shorts-to-ground, or an open on wire 144.
6. This step inspects for damage or corrosion to the TCM and engine control module connectors.
DTC P1891 Throttle Position Sensor PWM Signal Low Input
Step
1
2
3
4
5
6
7
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
Yes
Go to Step 2
1.
2.
3.
4.
Install the Allison DOC™ For PC–Service Tool. 9–18V (12V TCM)
Go to Step 3
18–32V (24V TCM)
Start the engine.
Record the failure records.
Using Allison DOC™ For PC–Service Tool,
measure ignition voltage.
Is ignition voltage within the specified value?
1. Operate the throttle while monitoring Allison
Go to
DOC™ For PC–Service Tool.
Diagnostic Aids.
2. Verify the throttle source is functioning correctly?
Is the PWM signal OK?
1. Turn OFF the ignition.
Go to Step 5
2. Disconnect the 80-way connector from the TCM.
3. Install the OEM-side of the J 47275 TCM
Breakout. Leave the TCM disconnected.
4. Disconnect the PWM throttle sensor connector.
5. Using a DVOM at J 47275-1 TCM Overlay, test
for opens, pin-to-pin shorts, or shorts-to-ground
on wire 144.
Were any wiring defects found?
NOTE: The vehicle OEM has responsibility for all
Go to Step 10
external wiring harness repairs. Harness repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Coordinate with the vehicle OEM to repair or
replace the vehicle wiring.
Is the repair complete?
Inspect the TCM and Engine Control Module
(ECM) connectors and terminals for damage and/or
corrosion.
Did you find a problem?
Repair and clean terminals if possible.
Is the repair complete?
Copyright © 2005 General Motors Corp.
Go to Step 7
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Resolve voltage
problem (refer to
DTC P0882 and
DTC P0883)
Go to Step 4
Go to Step 6
Go to Step 8
Go to Step 10
6–279
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P1891 Throttle Position Sensor PWM Signal Low Input (cont’d)
Step
8
9
10
6–280
Action
NOTE: The vehicle OEM has responsibility for the
PWM throttle sensor. PWM throttle sensor repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison warranty.
Value(s)
Coordinate with the vehicle OEM to troubleshoot
and replace the PWM throttle sensor.
Did a new PWM throttle sensor correct the problem?
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
Refer to TCM diagnostic procedure, Section 3–6.
Is Section 3–6 complete?
In order to verify your repair:
1. Clear the DTC.
2. Drive the vehicle under normal operating
conditions.
3. Using Allison DOC™ For PC–Service Tool,
monitor throttle percentage.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 10
No
Go to Step 9
Go to Step 10
Begin the
diagnosis again.
Go to Step 1
System OK
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P1892 Throttle Position Sensor PWM Signal High Input
END VIEW OF
20-WAY CONNECTOR
END VIEW OF
80-WAY CONNECTOR
1
6
7
10
11
14
15
20
61
80
41
60
21
40
1
20
TO RETARDER
CONTROL DEVICES
RETARDER
REQUEST SENSOR
(RESISTANCE
MODULE)
A
PWM
THROTTLE
SOURCE
B
C
TCM
THROTTLE
POSITION
SENSOR (TPS)
OR
ELECTRONIC
BRAKING (EBS)
RTDR PRESSURE
SENSOR
WIRE 156
WIRE 112
C
WIRE 144
B
WIRE 158
A
RETARDER TEMP
ENGINE TEMP
TRANSMISSION
ANALOG RETURN
OIL LEVEL
HALL
A
C
EFFECT
B
SUMP TEMP
19
16
15
18
PS1
NC*
* NORMALLY
3
WIRE 175
WIRE 135
56
RETARDER REQUEST SIGNAL
12
5V SENSOR VOLTAGE
44
THROTTLE POSITION OR
RTDR PRESSURE SIGNAL
58
ANALOG RETURN
75
RETARDER TEMP
35
ENGINE WATER TEMP
16
OIL LEVEL SENSOR
54
SUMP TEMP
77
PS1 DIAGNOSTIC
PRESSURE SWITCH
WIRE 158
WIRE 112
WIRE 116
WIRE 154
WIRE 177
CLOSED
V09069.01.00
Copyright © 2005 General Motors Corp.
6–281
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P1892 Throttle Position Sensor PWM Signal High Input
Circuit Description
The Transmission Control Module (TCM) can be calibrated to receive throttle information from a Pulse Width
Modulation (PWM) signal.
Conditions for Running the DTC
•
The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater
than 9V and less than 32V (24V TCM).
•
Engine speed is greater than 200 rpm and less than 7500 rpm for 5 seconds.
•
The TCM has autodetected a PWM throttle source.
Conditions for Setting the DTC
The TCM detects PWM throttle signal greater than or equal to 95.1 percent for 5 seconds.
Actions Taken When the DTC Sets
When DTC P1892 is active, the following conditions will occur:
•
The TCM does not illuminate the CHECK TRANS light.
•
DTC is stored in TCM history.
•
TCM uses default throttle values.
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
•
The TCM detects the throttle source automatically during the initial series of engine starts. The TCM may have
auto-detected the wrong throttle source type. Use the Allison DOC™ For PC–Service Tool to reset auto-detect
or select the appropriate throttle source if PWM-type sensor is not being used.
•
Inspect the wiring for poor electrical connections at the TCM and PWM throttle sensor. Look for the following
conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
•
When diagnosing for an intermittent short or open, massage the wiring harness while watching the test
equipment for a change.
•
You may have to drive the vehicle in order to experience a fault.
•
Advanced troubleshooting—monitor frequency on pin 44 as throttle is increased from closed throttle to wide
open throttle. if frequency does not vary, the signal is bad. Have the vehicle manufacturer replace the PWM
device.
6–282
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
Test Description
This DTC requires the use of the J 47275 TCM Breakout. The numbers below refer to step numbers on the
diagnostic table.
2.
3.
4.
6.
This step tests for proper ignition voltage.
This step tests for operation of the PWM throttle sensor.
This step tests for wire-to-wire shorts, shorts-to-ground, or an open on wire 144.
This step inspects for damage or corrosion to the TCM and engine control module connectors.
DTC P1892 Throttle Position Sensor PWM Signal High Input
Step
1
2
3
4
5
6
7
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
1.
2.
3.
4.
Install the Allison DOC™ For PC–Service Tool. 9–18V (12V TCM)
18–32V (24V TCM)
Start the engine.
Record the failure records.
Using Allison DOC™ For PC–Service Tool,
measure ignition voltage.
Is ignition voltage within the specified value?
1. Operate the throttle while monitoring Allison
DOC™ For PC–Service Tool.
2. Verify the throttle source is functioning correctly?
Is the PWM signal OK?
1. Turn OFF the ignition.
2. Disconnect the 80-way connector from the TCM.
3. Install the OEM-side of the 80-way connector to
the J 47275 TCM Breakout. Leave the TCM
disconnected.
4. Disconnect the PWM throttle sensor connector.
5. Using a DVOM at J 47275-1 TCM Overlay, test
for opens, pin-to-pin shorts, or shorts-to-ground
on wire 144.
Were any wiring defects found?
NOTE: The vehicle OEM has responsibility for all
external wiring harness repairs. Harness repairs
performed by Allison Transmission distributors
and dealers are not covered by Allison
Transmission warranty.
Coordinate with the vehicle OEM to repair or
replace the vehicle wiring.
Is the repair complete?
Inspect the TCM and Engine Control Module
(ECM) connectors and terminals for damage and/or
corrosion.
Did you find a problem?
Repair and clean terminals if possible.
Is the repair complete?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 2
Go to Step 3
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Resolve voltage
problem (refer to
DTC P0882 and
DTC P0883)
Go to
Diagnostic Aids
Go to Step 4
Go to Step 5
Go to Step 6
Go to Step 10
Go to Step 7
Go to Step 8
Go to Step 10
6–283
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P1892 Throttle Position Sensor PWM Signal High Input (cont’d)
Step
8
9
10
6–284
Action
NOTE: The vehicle OEM has responsibility for the
PWM throttle sensor. PWM throttle sensor repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison warranty.
Value(s)
Coordinate with the vehicle OEM to troubleshoot
and replace the PWM throttle sensor.
Did a new PWM throttle sensor correct the problem?
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
Refer to TCM diagnostic procedure, Section 3–6.
Is Section 3–6 complete?
In order to verify your repair:
1. Clear the DTC.
2. Drive the vehicle under normal operating
conditions.
3. Using Allison DOC™ For PC–Service Tool,
monitor throttle percentage.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 10
No
Go to Step 9
Go to Step 10
Begin the
diagnosis again.
Go to Step 1
System OK
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2184 Engine Coolant Temperature Sensor Circuit Low Input
END VIEW OF
20-WAY CONNECTOR
END VIEW OF
80-WAY CONNECTOR
1
6
7
10
11
14
15
20
61
80
41
60
21
40
1
20
TO RETARDER
CONTROL DEVICES
RETARDER
REQUEST SENSOR
(RESISTANCE
MODULE)
A
PWM
THROTTLE
SOURCE
B
C
TCM
THROTTLE
POSITION
SENSOR (TPS)
OR
ELECTRONIC
BRAKING (EBS)
RTDR PRESSURE
SENSOR
WIRE 156
WIRE 112
C
WIRE 144
B
WIRE 158
A
RETARDER TEMP
ENGINE TEMP
TRANSMISSION
ANALOG RETURN
OIL LEVEL
HALL
A
C
EFFECT
B
SUMP TEMP
19
16
15
18
PS1
NC*
* NORMALLY
3
WIRE 175
WIRE 135
56
RETARDER REQUEST SIGNAL
12
5V SENSOR VOLTAGE
44
THROTTLE POSITION OR
RTDR PRESSURE SIGNAL
58
ANALOG RETURN
75
RETARDER TEMP
35
ENGINE WATER TEMP
16
OIL LEVEL SENSOR
54
SUMP TEMP
77
PS1 DIAGNOSTIC
PRESSURE SWITCH
WIRE 158
WIRE 112
WIRE 116
WIRE 154
WIRE 177
CLOSED
V09069.01.00
Copyright © 2005 General Motors Corp.
6–285
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2184 Engine Coolant Temperature Sensor Circuit Low Input
Circuit Description
The Transmission Control Module (TCM) receives an input from an engine coolant temperature sensor. The TCM
supplies a 5V reference voltage signal into a voltage-sensing network that is connected to one side of the engine
coolant temp sensor via wire 135. The other side of the temp sensor is connected to the TCM analog ground wire 158.
The resistance value of the engine coolant temperature sensor determines the voltage drop in the engine coolant
temp sensor circuit. As resistance changes, the voltage drop across the temp sensor circuit will also change varying
the sensor input voltage on wire 135. The TCM uses engine coolant temperature information to restrict retarder
operation when an engine coolant over-heat condition is detected.
Conditions for Running the DTC
• The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater
than 9V and less than 32V (24V TCM).
•
Engine speed is greater than 200 rpm and less than 7500 rpm for 5 seconds.
•
The TCM has autodetected the following:
— Retarder
— Analog engine coolant temperature sensor
— PWM retarder request source.
The “Retarder reduction and preselect based on engine coolant temperature” feature is enabled in the
calibration.
•
Conditions for Setting the DTC
The TCM detects engine coolant temperature greater than a calibrated value for more than 10 seconds.
Actions Taken When the DTC Sets
When DTC P2184 is active, the following conditions will occur:
•
•
•
The TCM does not illuminate the CHECK TRANS light.
DTC is stored in TCM history.
The TCM uses default engine coolant values.
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
• DTC P2184 may be caused by a short-to-ground on wire 135.
•
Review Appendix A for diagnosing intermittent electrical conditions.
•
Inspect the wiring for poor electrical connections at the TCM and engine coolant temp sensor. Look for the
following conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
6–286
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
•
When diagnosing for an intermittent short or open, massage the wiring harness while watching the test
equipment for a change.
•
You may have to drive the vehicle in order to experience a fault.
Test Description
This DTC requires the use of the J 47275 TCM Breakout. The numbers below refer to step numbers on the
diagnostic table.
2. This step tests for proper ignition voltage.
3. This step verifies which condition has set the DTC P2184.
4. This step tests for the proper 5V reference voltage at TCM.
5. This step tests for wire-to-wire shorts, shorts-to-ground, or an open in wires 135 (engine coolant temp)
and wire 112 (5V reference).
DTC P2184 Engine Coolant Temperature Sensor Circuit Low Input
Step
1
2
3
4
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
1.
2.
3.
4.
Install the Allison DOC™ For PC–Service Tool. 9–18V (12V TCM)
18–32V (24V TCM)
Start the engine.
Record failure record.
Using Allison DOC™ For PC–Service Tool,
measure ignition voltage.
Is ignition voltage within the specified value?
1. Clear the DTCs.
>174.11°C
(345.4°F)
2. Monitor the engine coolant temperature on
Allison DOC™ For PC–Service Tool.
3. Drive the vehicle and observe Allison DOC™ For
PC–service tool for an unrealistically high
temperature condition.
Is the Allison DOC™ For PC–Service Tool
transmission fluid temperature greater than
174.11°C (345.4°F)?
1. Turn OFF the ignition.
4.75 to 5.0V
2. Install J 47275 TCM Breakout at the TCM.
3. Disconnect the engine coolant temp sensor
connector.
4. Turn ON the ignition.
5. At J 47275-1 TCM Overlay connect a DVOM
and measure voltage between pins 35 and 58.
Is the voltage within the specified value?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 2
Go to Step 3
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Resolve voltage
problem (refer to
DTC P0882 and
DTC P0883)
Go to Step 4
Go to
Diagnostic Aids
Go to Step 7
Go to Step 5
6–287
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2184 Engine Coolant Temperature Sensor Circuit Low Input (cont’d)
Step
5
6
7
8
9
6–288
Action
1. Turn OFF the ignition.
2. Disconnect J 47275 TCM Breakout from the
TCM. Leave the OEM-side connected.
3. Disconnect the engine coolant temp sensor
connector, if not disconnected in Step 4.
4. Using a DVOM at J 47275-1 TCM Overlay, test
for pin-to-pin shorts, or shorts-to-ground, at
pin 35.
Were any wiring defects found?
NOTE: The vehicle OEM has responsibility for all
external wiring harness repairs. Harness repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Value(s)
Coordinate with the vehicle OEM to repair or
replace the vehicle wiring.
Is the repair complete?
NOTE: The vehicle OEM has responsibility for the
engine coolant temp sensor. Engine coolant
temperature sensor repairs performed by Allison
Transmission distributors and dealers are not
covered by Allison warranty.
Coordinate with the vehicle OEM to troubleshoot
and replace the engine coolant temp sensor.
Is replacement complete?
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
Refer to TCM diagnostic procedure, Section 3–6.
Is Section 3–6 complete?
In order to verify your repair:
1. Clear the DTC.
2. Using Allison DOC™ For PC–Service Tool,
monitor the engine coolant temperature.
3. Drive the vehicle under normal operating
conditions. Watch for significant change in
engine coolant temperature.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 6
No
Go to Step 8
Go to Step 9
Go to Step 9
Go to Step 9
Begin the
diagnosis again.
Go to Step 1
System OK
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2185 Engine Coolant Temperature Sensor Circuit High Input
END VIEW OF
20-WAY CONNECTOR
END VIEW OF
80-WAY CONNECTOR
1
6
7
10
11
14
15
20
61
80
41
60
21
40
1
20
TO RETARDER
CONTROL DEVICES
RETARDER
REQUEST SENSOR
(RESISTANCE
MODULE)
A
PWM
THROTTLE
SOURCE
B
C
TCM
THROTTLE
POSITION
SENSOR (TPS)
OR
ELECTRONIC
BRAKING (EBS)
RTDR PRESSURE
SENSOR
WIRE 156
WIRE 112
C
WIRE 144
B
WIRE 158
A
RETARDER TEMP
ENGINE TEMP
TRANSMISSION
ANALOG RETURN
OIL LEVEL
HALL
A
C
EFFECT
B
SUMP TEMP
19
16
15
18
PS1
NC*
* NORMALLY
3
WIRE 175
WIRE 135
56
RETARDER REQUEST SIGNAL
12
5V SENSOR VOLTAGE
44
THROTTLE POSITION OR
RTDR PRESSURE SIGNAL
58
ANALOG RETURN
75
RETARDER TEMP
35
ENGINE WATER TEMP
16
OIL LEVEL SENSOR
54
SUMP TEMP
77
PS1 DIAGNOSTIC
PRESSURE SWITCH
WIRE 158
WIRE 112
WIRE 116
WIRE 154
WIRE 177
CLOSED
V09069.01.00
Copyright © 2005 General Motors Corp.
6–289
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2185 Engine Coolant Temperature Sensor Circuit High Input
Circuit Description
The Transmission Control Module (TCM) receives an input from an engine coolant temperature sensor. The TCM
supplies a 5V reference voltage signal into a voltage-sensing network that is connected to one side of the engine
coolant temp sensor via wire 135. The other side of the temp sensor is connected to the TCM analog ground wire 158.
The resistance value of the engine coolant temp sensor determines the voltage drop in the engine coolant temp
sensor circuit. As resistance changes, the voltage drop across the temp sensor circuit will also change varying the
sensor input voltage on wire 135.
Conditions for Running the DTC
• The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater
than 9V and less than 32V (24V TCM).
• Engine speed is greater than 200 rpm and less than 7500 rpm for 5 seconds.
• The TCM has autodetected the following:
— Retarder
— Analog engine coolant temperature sensor
— PWM retarder request source.
• The “Retarder reduction and preselect based on engine coolant temperature” feature is enabled in the
calibration.
Conditions for Setting the DTC
The TCM detects engine coolant temperature less than or equal to a calibrated value for more than 2.5 seconds.
Actions Taken When the DTC Sets
When DTC P2185 is active, the following conditions will occur:
• The TCM does not illuminate the CHECK TRANS light.
• DTC is stored in TCM history.
• The TCM uses default engine coolant values.
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
• DTC P2185 may be caused by an open on wire 135 or 158.
• DTC P2185 may be caused by a short-to-battery on wire 135. If DTC P2185 is accompanied by a DTC P0713
and/or P2743, the problem is likely a short-to-battery on wire 154, wire 135, or wire 175.
• Review Appendix A for diagnosing intermittent electrical fault conditions.
• Inspect the wiring for poor electrical connections at the TCM and engine coolant temp sensor. Look for the
following conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
6–290
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
•
When diagnosing for an intermittent short or open, massage the wiring harness while watching the test
equipment for a change.
•
You may have to drive the vehicle in order to experience a fault.
Test Description
This DTC requires the use of the J 47275 TCM Breakout. The numbers below refer to step numbers on the
diagnostic table.
2. This step tests for proper transmission fluid level and condition.
3. This step verifies which condition has set the DTC P2185.
4. This step tests for the proper 5V reference voltage at TCM.
5. This step tests for wiring defects in the OEM chassis harness.
DTC P2185 Engine Coolant Temperature Sensor Circuit High Input
Step
1
2
3
4
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
1.
2.
3.
4.
Install the Allison DOC™ For PC–Service Tool. 9–18V (12V TCM)
18–32V (24V TCM)
Start the engine.
Record failure record.
Using Allison DOC™ For PC–Service Tool,
measure ignition voltage.
Is ignition voltage within the specified value?
1. Clear the DTCs.
≤–42°C (–43.75°F)
2. Monitor the engine coolant temperature on
Allison DOC™ For PC–Service Tool.
3. Drive the vehicle and observe Allison DOC™ For
PC–Service Tool for an unrealistically low
temperature condition.
Is the Allison DOC™ For PC–Service Tool engine
coolant temperature less than or equal to –42°C
(–43.75°F)?
1. Turn OFF the ignition.
4.75 to 5.0V
2. Install J 47275 TCM Breakout at the TCM.
3. Disconnect the engine coolant temp sensor
connector.
4. Turn ON the ignition.
5. At J 47275-1 TCM Overlay connect a DVOM
and select the volts-DC scale.
6. Measure voltage between pin 35 and an isolated
ground.
Is the voltage within the specified value?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 2
Go to Step 3
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Resolve voltage
problem (refer to
DTC P0882 and
DTC P0883)
Go to Step 4
Go to
Diagnostic Aids
Go to Step 7
Go to Step 5
6–291
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2185 Engine Coolant Temperature Sensor Circuit High Input (cont’d)
Step
5
6
7
8
9
6–292
Action
1. Turn OFF the ignition.
2. Disconnect the TCM from the J 47275 TCM
Breakout. Leave the OEM-side connected.
3. Disconnect the engine coolant temperature
sensor, if not disconnected in Step 4.
4. Disconnect the transmission 20-way connector
and retarder temperature sensor.
5. Using a DVOM at J 47275-1 TCM Overlay, test
for opens in wires 135 and 158.
6. Also test for wire-to-wire shorts, or shorts-tobattery on wire 135, wire 154, or wire 175.
Were any wiring defects found?
NOTE: The vehicle OEM has responsibility for all
external wiring harness repairs. Harness repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Value(s)
Coordinate with the vehicle OEM to repair or
replace the vehicle wiring.
Is the repair complete?
NOTE: The vehicle OEM has responsibility for the
engine coolant temp sensor. Engine coolant
temperature sensor repairs performed by Allison
Transmission distributors and dealers are not
covered by Allison warranty.
Coordinate with the vehicle OEM to troubleshoot
and replace the engine coolant temp sensor.
Is replacement complete?
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
Refer to TCM diagnostic procedure, Section 3–6.
Is Section 3–6 complete?
In order to verify your repair:
1. Clear the DTC.
2. Using Allison DOC™ For PC–Service Tool,
monitor the engine coolant temperature.
3. Drive the vehicle under normal operating
conditions. Watch for significant change in
engine coolant temperature.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 6
No
Go to Step 8
Go to Step 9
Go to Step 9
Go to Step 9
Begin the
diagnosis again.
Go to Step 1
System OK
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2637 Torque Management Feedback Signal (SEM)
No Schematic for this DTC
Circuit Description
Shift Energy Management (SEM) allows the Transmission Control Module (TCM) to request torque reduction
from the engine controller. By reducing torque, shifts can be made quicker, at a more consistent output torque
which reduces clutch temperatures and increases clutch life.
Conditions for Running the DTC
•
The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater
than 9V and less than 32V (24V TCM).
•
Engine speed is greater than 200 rpm but less than 7500 rpm for 5 seconds.
•
SEM is enabled in the calibration.
Conditions for Setting the DTC
DTC P2637 sets when the TCM detects one of the following conditions for a minimum of four up shifts
(consecutive or non-consecutive) during one drive cycle:
•
Engine ECM is not responding to SEM torque reduction signal request from the TCM.
•
A non-approved J1939 device is interfering with the SEM torque reduction signal request.
Actions Taken When the DTC Sets
When DTC P2637 is active, the following conditions will occur:
•
The CHECK TRANS light illuminates.
•
DTC is stored in TCM history.
•
SEM operation is not active.
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the actual engine torque follows TCM commanded torque
for 20 consecutive up-shifts in the same ignition cycle.
Diagnostic Aids
It will be necessary to drive the vehicle with heavy to moderate throttle settings for at least four up-shift cycles in
order to set a DTC P2637.
When a DTC P2637 is set with a P0614, start troubleshooting with P0614 first. This combination of DTCs
indicates that AUTOSELECT was active and engine software is not correct.
Test Description
The numbers below refer to step numbers on the diagnostic table.
2. This step tests for presence of DTC P0614.
3. This step tests for proper ECM SEM torque request response.
4. This step tests to identify the device causing the torque request to be ignored.
5. This step tests for the offending device by removing it from the J1939 network.
6. This step tests for the presence of proper engine controller software.
Copyright © 2005 General Motors Corp.
6–293
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2637 Torque Management Feedback Signal (SEM)
Step
1
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
2
If DTC P0614 is present, troubleshoot and resolve
before going to the next step.
3
1. Install the Allison DOC™ For PC–Service Tool.
Allison DOC™
2. Turn ON the ignition.
diagnostic tool
3. Refer to the SEM torque reduction status in SEM/
indicates
LRTP AUTODECT INFO display of Allison
“correct response”
DOC™ For PC–Service Tool.
or “incorrect
Does Allison DOC™ For PC–Service Tool indicate
response”
the ECM response to SEM torque reduction as
INCORRECT?
Use Allison DOC™ For PC–Service Tool to identify
Allison DOC™
an unapproved SEM torque reduction device.
diagnostic tool
Is the unapproved device one of the following?
shows the actual
1. Engine or transmission?
device at fault
2. Null Address (N/A) or All/Any (info not valid)?
1. If Allison DOC™ For PC–Service Tool is
indicating another device such as brakes, cruise
control, headway controller etc., inspect the
controller for the device indicated.
2. If possible eliminate the device by disconnecting
it from the J1939 CAN backbone.
NOTE: It may be possible that the device causing
the interruption is only triggered under certain
circumstances. For example, a brake controller
may only send commands under certain road
conditions. Since these conditions may not be easily
repeatable, replacement with a known good
controller may be the only way to verify the failure.
3. If necessary to confirm the failure, test the system
with a known good controller.
Was the device causing the problem replaced or
repaired?
1. Verify that compatible engine controller software
is being used.
2. If the software is correct, turn the vehicle over to
the engine manufacturer to replace the engine
controller.
3. If neither solves the problem, use an engine
torque/power rating that does not require SEM.
Was the software updated or engine controller
replaced?
4
5
6
6–294
Value(s)
Copyright © 2005 General Motors Corp.
Yes
Go to Step 2
Go to DTC P0614
and resolve before
proceeding to
Step 3
Go to Step 6
Go to Step 6
Go to Step 7
Go to Step 7
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Go to Step 3
Go to Step 4
Go to Step 5
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2637 Torque Management Feedback Signal (SEM) (cont’d)
Step
7
Action
In order to verify your repair:
1. Install Allison DOC™ For PC–Service Tool.
2. Clear the DTC.
3. Drive the vehicle under moderate to heavy
throttle setting for at least four up shift cycles.
4. Attempt to duplicate conditions when DTC was
set (cruise control, headway controls, ABS, etc.).
Did the DTC return?
Value(s)
Copyright © 2005 General Motors Corp.
Yes
Begin the
diagnosis again.
Go to Step 1
No
System OK
6–295
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2641 Torque Management Feedback Signal (LRTP)
No Schematic for this DTC
Circuit Description
Lower Range Torque Protection (LRTP) protects the transmission during low vehicle speed conditions. When an
engine torque rating exceeds a predetermined value, LRTP limits engine torque in lower ranges to protect the
transmission from damage during a converter stall condition.
Conditions for Running the DTC
• The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater
than 9V and less than 32V (24V TCM).
•
Engine speed is greater than 200 rpm but less than 7500 rpm for 5 seconds.
•
LRTP is enabled in the calibration.
Conditions for Setting the DTC
DTC P2641 sets when the TCM detects one of the following conditions for a minimum of four up shifts
(consecutive or non-consecutive) during one drive cycle:
•
Engine ECM is not responding to LRTP torque reduction signal request from the TCM.
•
A non-approved J1939 device is interfering with the LRTP torque reduction signal request.
Actions Taken When the DTC Sets
When DTC P2641 is active, the following conditions will occur:
•
The CHECK TRANS light illuminates.
•
DTC is stored in TCM history.
•
LRTP operation is not active.
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
It may be necessary to drive the vehicle in order to set a DTC P2641.
When a DTC P2641 is set with a P0614, start troubleshooting with P0614 first. This combination of DTCs
indicates that AUTOSELECT was still active and the engine software is not correct.
Test Description
The numbers below refer to step numbers on the diagnostic table.
2. This step tests for the presence of DTC P0614.
3. This step tests for proper ECM LRTP torque request response.
4. This step tests to identify the device causing the torque request to be ignored.
5. This step tests for the offending device by removing it from the J1939 network.
6. This step tests for the presence of proper engine controller software.
6–296
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2641 Torque Management Feedback Signal—LRTP
Step
1
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
2
If DTC P0614 is present, troubleshoot and resolve
before going to the next step.
3
1. Install the Allison DOC™ For PC–Service Tool.
2. Turn ON the ignition.
3. Refer to LRTP torque reduction status in SEM/
LRTP AUTODETECT INFO display of Allison
DOC™ For PC–Service Tool.
Does Allison DOC™ For PC–Service Tool indicate
the ECM response to LRTP torque reduction as
INCORRECT?
Use Allison DOC™ For PC–Service Tool to identify
an unapproved LRTP torque reduction device.
Is the unapproved device one of the following?
1. Engine?
2. Null Address (N/A) or All/Any (info not valid)?
1. If Allison DOC™ For PC–Service Tool is
indicating another device such as brakes, cruise
control, headway controller etc., inspect the
controller for the device indicated.
2. If possible eliminate the device by disconnecting
it from the J1939 CAN backbone.
4
5
6
Value(s)
Allison DOC™
diagnostic tool
indicates “correct
response” or
“incorrect
response”
Allison DOC™
For PC–Service
Tool shows the
Yes
Go to Step 2
Go to DTC P0614
and resolve before
proceeding to
Step 3
Go to Step 6
Go to Step6
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Go to Step 3
Go to Step 4
Go to Step 5
actual device at
fault
NOTE: It may be possible that the device causing
the interruption is only triggered under certain
circumstances. For example, a brake controller
may only send commands under certain road
conditions. Since these conditions may not be easily
repeatable, replacement with a known good
controller may be the only way to verify the failure.
3. If necessary to confirm the failure, test the system
with a known, good controller.
Was the device causing the problem replaced or
repaired?
1. Verify that compatible engine controller software
is being used.
2. If the software is correct, turn the vehicle over to
the engine manufacturer to replace the engine
controller.
3. If neither solves the problem, use an engine
torque/power rating that does not require LRTP.
Was the software updated or engine controller
replaced?
Copyright © 2005 General Motors Corp.
Go to Step 7
Go to Step 7
6–297
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2641 Torque Management Feedback Signal—LRTP (cont’d)
Step
7
6–298
Action
In order to verify your repair:
1. Install Allison DOC™ For PC–Service Tool.
2. Clear the DTC.
3. Drive the vehicle. Refer to Allison DOC™ For
PC–Service Tool “Test Passed” section and
confirm the test was run.
4. Attempt to duplicate the conditions when the
DTC was set (loads, grades, road conditions).
Did the DTC return?
Value(s)
Copyright © 2005 General Motors Corp.
Yes
Begin the
diagnosis again.
Go to Step 1
No
System OK
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2670 Actuator Supply Voltage 2 (HSD2) Low
END VIEW OF
80-WAY CONNECTOR
END VIEW OF
20-WAY CONNECTOR
1
6
7
10
11
14
15
20
61
80
41
60
21
40
1
20
TRANSMISSION
HSD2
PCS1
PCS2
PCS3
SS1
TCM
6
4
5
9
10
WIRE 171
WIRE 136
WIRE 152
WIRE 133
WIRE 151
71
HSD2
V BATTERY
36
52
33
51
V09067.00.00
Circuit Description
High Side Driver 2 (HSD2) supplies battery voltage to the PCS1, PCS2, PCS3, and SS1 solenoids via wire 171.
HSD2 is continuously ON during normal operation except during brief circuit tests. The TCM regulates control
current to the solenoids by switching the appropriate Low Side Driver (LSD) ON and OFF. DTC P2670 indicates
the TCM has detected a supply voltage in the HSD2 circuit of 6V or less. DTC P2670 could be caused by a shortto-ground in the high side wiring attached to HSD2 (wire 171).
Conditions for Running the DTC
• The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater
than 9V and less than 32V (24V TCM).
• HSD2 is commanded ON.
• Engine speed greater than 200 rpm.
Conditions for Setting the DTC
DTC P2670 is set when the TCM detects a low voltage condition (less than 6V) in three solenoids in the HSD2
circuit.
Actions Taken When the DTC Sets
When DTC P2670 is active, the following conditions will occur:
•
•
•
The CHECK TRANS light illuminates.
DTC is stored in TCM history.
Hydraulic default (SOL OFF) is commanded. The shift selector position and hydraulic state of latch valves
determines the range attained.
Copyright © 2005 General Motors Corp.
6–299
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2670 Actuator Supply Voltage 2 (HSD2) Low
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
•
You may have to drive the vehicle in order to experience a fault. Use the data obtained from failure records to
determine transmission range and/or certain vehicle operating variables such as temperature, run time etc. This
data can be useful in reproducing the failure mode when DTC was set.
•
Inspect the wiring for poor electrical connections at the TCM and transmission connector. Look for the
following conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
•
Inspect OEM wiring harness routing, look for possible contact points where chafing could occur leading to an
open or short circuit condition. Moving parts on the vehicle could be contacting the harness; this includes
parking brake drum, suspension components, etc.
•
When diagnosing for an intermittent short or open, massage the wiring harness while watching the test
equipment for a change.
Test Description
This DTC requires the use of the J 47275 TCM Breakout and J 47279 Transmission Breakout. The numbers below
refer to step numbers on the diagnostic table.
2. This step tests for the proper ignition voltage.
3. This step tests for an active DTC.
4. This step tests for a wire-to-wire short, or short-to-ground in the wire 171 of the OEM chassis harness.
6. This step tests for wiring defects in the transmission internal harness.
DTC P2670 Actuator Supply Voltage 2 (HSD2) Low
Step
1
2
6–300
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
1. Install the Allison DOC™ For PC–Service Tool. 9–18V (12V TCM)
18–32V (24V TCM)
2. Start the engine.
3. Record the failure records.
4. Monitor ignition voltage.
Is voltage within the specified values?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 2
Go to Step 3
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Resolve voltage
problems
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2670 Actuator Supply Voltage 2 (HSD2) Low (cont’d)
Step
3
Action
1. Clear the DTC.
2. Start the engine and test drive the vehicle.
3. Attempt to duplicate the same conditions
observed in the failure records (range attained,
temperature, etc.).
Value(s)
Yes
Go to Step 4
No
Go to
Diagnostic Aids
Go to Step 5
Go to Step 6
NOTE: This DTC is intended to detect a short-toground condition in the HSD2 electrical circuit.
4
5
6
Did DTC P2670 return?
NOTE: Review Section 4—Wire Test Procedures
before performing steps.
1. Turn OFF the ignition.
2. Disconnect the 80-way connectors at the TCM.
3. Install the OEM-side of the J 47275 TCM
Breakout. Leave the TCM disconnected.
4. Disconnect the OEM-side 20-way connector
from the transmission.
5. Inspect the routing of wire 171 in the chassis
harness between the TCM and the transmission
connector.
6. At J 47275-1 TCM Overlay, test for wire-to-wire
shorts between pin 71 and all other pins in the
80-way connector, and test for shorts-to-ground
between pin 71 and chassis ground.
Were any wire-to-wire shorts or shorts-to-ground
found?
NOTE: The vehicle OEM has responsibility for all
external wiring harness repairs. Harness repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Coordinate with the vehicle OEM to repair or
replace the chassis harness.
Is the repair complete?
1. Turn OFF the ignition.
2. Install the transmission 20-way connector to the
J 47279 Transmission Breakout. Leave the
OEM-side disconnected.
3. Using a DVOM at J 47279-1 Transmission
Overlay, test for wire-to-wire shorts between pin
6 and all other pins in the 20-way connector, and
shorts-to-ground between pin 6 and chassis
ground.
Go to Step 9
Go to Step 7
Go to Step 8
NOTE: The resistance value between pins 6 and 4,
between pins 6 and 5, between pins 6 and 9, and
between pins 6 and 10 will read normal solenoid
resistance.
Were any opens, wire-to-wire shorts or shorts-toground found?
Copyright © 2005 General Motors Corp.
6–301
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2670 Actuator Supply Voltage 2 (HSD2) Low (cont’d)
Step
7
8
9
6–302
Action
1. Remove the hydraulic control module assembly.
2. Repair or replace the internal wiring harness.
Is the repair complete?
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
Value(s)
Refer to TCM Diagnostic Procedure, Section 3–6.
Is Section 3–6 complete?
In order to verify your repair:
1. Clear the DTC.
2. Drive the vehicle under conditions noted in
failure records.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 9
No
Go to Step 9
Begin the
diagnosis again.
Go to Step 1
System OK
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2671 Actuator Supply Voltage 2 (HSD 2) High
END VIEW OF
80-WAY CONNECTOR
END VIEW OF
20-WAY CONNECTOR
1
6
7
10
11
14
15
20
61
80
41
60
21
40
1
20
TRANSMISSION
HSD2
PCS1
PCS2
PCS3
SS1
TCM
WIRE 171
6
WIRE 136
4
WIRE 152
5
WIRE 133
9
WIRE 151
10
71
HSD2
V BATTERY
36
52
33
51
V09067.00.00
Circuit Description
High Side Driver 2 (HSD2) supplies battery voltage to the PCS1, PCS2, PCS3, and SS1 solenoids via wire 171.
HSD2 is continuously ON during normal operation except during brief circuit tests. The TCM regulates control
current to the solenoids by switching the appropriate Low Side Driver (LSD) ON and OFF. DTC P2671 indicates the
TCM has detected greater than or equal to 6V in the HSD2 circuit when HSD2 is OFF during TCM initialization.
DTC P2671 could be caused by an open or short-to-battery in the high side wiring attached to HSD2 (wire 171).
Conditions for Running the DTC
•
The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater
than 9V and less than 32V (24V TCM).
•
HSD2 is commanded ON.
•
Engine speed greater than 200 rpm.
Conditions for Setting the DTC
DTC P2671 is set when the TCM detects a high voltage condition (> 6V) in the HSD2 circuit after two solenoids
indicate a failure.
Copyright © 2005 General Motors Corp.
6–303
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2671 Actuator Supply Voltage 2 (HSD 2) High
Actions Taken When the DTC Sets
When DTC P2671 is active, the following conditions will occur:
•
The CHECK TRANS light illuminates.
•
DTC is stored in TCM history.
•
Hydraulic default (SOL OFF) is commanded. The shift selector position and hydraulic state of latch valves
determines the range attained.
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
•
You may have to drive the vehicle in order to experience a fault. Use the data obtained from failure records to
determine transmission range and/or certain vehicle operating variables such as temperature, run time etc. This
data can be useful in reproducing the failure mode when DTC was set.
•
Inspect the wiring for poor electrical connections at the TCM and transmission connector. Look for the
following conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
•
Inspect OEM wiring harness routing, look for possible contact points where chafing could occur leading to an
open or short circuit condition. Moving parts on the vehicle could be contacting the harness; this includes
parking brake drum, suspension components, etc.
•
When diagnosing for an intermittent short or open, massage the wiring harness while watching the test
equipment for a change.
Test Description
This DTC requires the use of the J 47275 TCM Breakout and J 47279 Transmission Breakout. The numbers below
refer to step numbers on the diagnostic table.
2. This step tests for the proper ignition voltage.
3. This step tests for an active DTC.
4. This step tests for an open in wire 171 of OEM chassis harness.
5. This step tests for a wire-to-wire short, or short-to-battery in the wire 171 of the OEM chassis harness.
7. This step tests for wiring defects in the transmission internal harness.
6–304
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2671 Actuator Supply Voltage 2 (HSD2) High
Step
1
2
3
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
1. Install the Allison DOC™ For PC–Service Tool. 9–18V (12V TCM)
18–32V (24V TCM)
2. Start the engine.
3. Record the failure records.
4. Monitor ignition voltage.
Is voltage within the specified values?
1. Clear the DTC.
2. Start the engine and test drive the vehicle.
3. Attempt to duplicate the same conditions
observed in the failure records (range attained,
temperature, etc.).
Yes
Go to Step 2
Go to Step 3
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Resolve voltage
problems
Go to Step 4
Go to
Diagnostic Aids
Go to Step 6
Go to Step 5
NOTE: This DTC is intended to detect an open or
short-to-battery condition in the HSD2 electrical
circuit.
4
Did DTC P2671 return?
1. Turn OFF the ignition.
2. Install the J 47275 TCM Breakout at the TCM
80-way connector.
3. Install J 47275 TCM Breakout at the transmission
20-way connector.
4. Turn ON the ignition, leave the engine OFF.
5. Using Allison DOC™ For PC–Service Tool, enter
Solenoid Test mode and command PCS3 ON.
6. Determine the voltage drop in the HSD2 circuit
as follows:
• At J 47275-1 TCM Overlay, measure voltage
between pin 71 and an isolated ground.
• At J 47279-1 Transmission Overlay, measure
voltage between pin 6 and isolated ground.
• Subtract the two voltage measurements to
obtain the voltage drop in the circuit.
NOTE: A voltage drop of more than 0.5V indicates
an excessive voltage loss in the OEM harness.
Did the high-side voltage drop exceed 0.5VDC?
Copyright © 2005 General Motors Corp.
6–305
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2671 Actuator Supply Voltage 2 (HSD2) High (cont’d)
Step
5
6
7
Action
1. Turn OFF the ignition.
2. Disconnect the TCM from the J 47275 harness.
Leave the OEM-side connected.
3. Disconnect the OEM-side of the 20-way
connector J 47279 Transmission Breakout. Leave
the transmission-side connected.
4. Inspect the routing of wire 171 in the chassis
harness between the TCM and the transmission
connector.
5. At J 47275-1 TCM Overlay, test for wire-to-wire
shorts between pin 71 and all other pins in the
80-way connector.
Were any wire-to-wire shorts found?
NOTE: The vehicle OEM has responsibility for all
external wiring harness repairs. Harness repair
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Value(s)
Coordinate with the vehicle OEM to repair or
replace the vehicle wiring.
Is the repair complete?
1. Turn OFF the ignition.
2. Verify the J 47279 Transmission Breakout is
installed at the transmission 20-way connector
and the OEM-side is disconnected.
3. Using a DVOM at J 47279-1 Transmission
Overlay, test for wire-to-wire shorts between pin
6 and all other pins in the 20-way connector.
Yes
Go to Step 6
No
Go to Step 7
Got to Step 10
Go to Step 8
Go to Step 9
NOTE: The resistance value between pins 6 and 4,
between pins 6 and 5, between pins 6 and 9, and
between pins 6 and 10 will read normal solenoid
resistance. Refer to Solenoid Resistance chart for
these values.
8
9
10
6–306
Were any wire-to-wire shorts found?
1. Remove the hydraulic control module assembly.
2. Repair or replace the internal wiring harness.
Is the repair complete?
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
Refer to TCM diagnostic procedure, Section 3–6.
Is Section 3–6 complete?
In order to verify your repair:
1. Clear the DTC.
2. Drive the vehicle under conditions noted in
failure records.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Go to Step 10
Go to Step 10
Begin the
diagnosis again.
Go to Step 1
System OK
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2685 Actuator Supply Voltage 3 (HSD3) Low
END VIEW OF
20-WAY CONNECTOR
END VIEW OF
80-WAY CONNECTOR
1
6
7
10
11
14
15
20
61
80
41
60
21
40
1
20
TRANSMISSION
HSD3
TCC
SS2
TCM
11
12
17
WIRE 131
WIRE 137
WIRE 119
(7-SPEED MODELS)
31
HSD3
V BATTERY
37
19
15
RTDR ACCUM
HSD3
SS2
B
A
WIRE 131
WIRE 119
RTDR OR
DIFF LOCK (T-CASE)
HSD3
PCS5
B
A
WIRE 131
WIRE 115
V09068.00.00
Circuit Description
High Side Driver 3 (HSD3) supplies battery voltage to the TCC, PCS5 (retarder and 7-speed models) and SS2 (also,
retarder and 7-speed models) solenoids via wire 131. HSD3 is continuously ON during normal operation except
during brief circuit tests. The TCM regulates control current to the solenoids by switching the appropriate Low Side
Driver (LSD) ON and OFF. DTC P2685 indicates the TCM has detected a supply voltage in the HSD3 circuit of 6V
or less. DTC P2685 could be caused by a short-to-ground in the high side wiring attached to HSD3 (wire 131).
Conditions for Running the DTC
• The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater
than 9V and less than 32V (24V TCM).
• HSD3 is commanded ON.
• Engine speed greater than 200 rpm.
Copyright © 2005 General Motors Corp.
6–307
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2685 Actuator Supply Voltage 3 (HSD 3) Low
Conditions for Setting the DTC
DTC P2685 is set when the TCM detects a low voltage condition (less than 6V) in two solenoids in the HSD3
circuit.
Actions Taken When the DTC Sets
When DTC P2685 is active, the following conditions will occur:
•
The CHECK TRANS light illuminates.
•
DTC is stored in TCM history.
•
Hydraulic default (SOL OFF) is commanded. The shift selector position and hydraulic state of latch valves
determines the range attained.
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
•
You may have to drive the vehicle in order to experience a fault. Use the data obtained from failure records to
determine transmission range and/or certain vehicle operating variables such as temperature, run time etc. This
data can be useful in reproducing the failure mode when DTC was set.
•
Inspect the wiring for poor electrical connections at the TCM and transmission connector. Look for the
following conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
•
Inspect OEM wiring harness routing, look for possible contact points where chafing could occur leading to an
open or short circuit condition. Moving parts on the vehicle could be contacting the harness; this includes
parking brake drum, suspension components, etc.
•
When diagnosing for an intermittent short or open, massage the wiring harness while watching the test
equipment for a change.
Test Description
This DTC requires the use of the J 47275 TCM Breakout and J 47279 Transmission Breakout. The numbers below
refer to step numbers on the diagnostic table.
2. This step tests for the proper ignition voltage.
3. This step tests for an active DTC.
4. This step tests for a wire-to-wire short, or short-to-ground in the wire 131 of the OEM chassis harness.
6. This step tests for wiring defects in the transmission internal harness.
6–308
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2685 Actuator Supply Voltage 3 (HSD 3) Low
Step
1
2
3
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
1. Install the Allison DOC™ For PC–Service Tool. 9–18V (12V TCM)
18–32V (24V TCM)
2. Start the engine.
3. Record the failure records.
4. Monitor ignition voltage.
Is voltage within the specified values?
1. Clear the DTC.
2. Start the engine and test drive the vehicle.
3. Attempt to duplicate the same conditions
observed in the failure records (range attained,
temperature, etc.).
Yes
Go to Step 2
Go to Step 3
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Resolve voltage
problems
Go to Step 4
Go to
Diagnostic Aids
Go to Step 5
Go to Step 6
NOTE: This DTC is intended to detect a short-toground condition in the HSD3 electrical circuit.
4
5
Did DTC P2685 return?
1. Turn OFF the ignition.
2. Disconnect the 80-way connector at the TCM.
3. Install the OEM-side of the 80-way connector to
the J 47275 TCM Breakout. Leave the TCM
disconnected.
4. Disconnect the OEM 20-way connector from the
transmission.
5. For retarder transmissions, disconnect the SS2
(accumulator) and PCS5 (retarder control)
connectors.
6. For 3000 7-speed only, disconnect the T-case
electrical connector.
7. Inspect the routing of wire 131 in the chassis
harness between the TCM and the transmission
connectors.
8. At J 47275-1 TCM Overlay, test for wire-to-wire
shorts between pin 31 and all other pins in the
80-way connector, and test for shorts-to-ground
between pin 31 and chassis ground.
Were any wire-to-wire shorts or shorts-to-ground
found?
NOTE: The vehicle OEM has responsibility for all
external wiring harness repairs. Harness repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Go to Step 12
Coordinate with the vehicle OEM to repair or
replace the chassis harness.
Is the repair complete?
Copyright © 2005 General Motors Corp.
6–309
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2685 Actuator Supply Voltage 3 (HSD 3) Low (cont’d)
Step
6
Action
1. Turn OFF the ignition.
2. Install the transmission 20-way connector to the
J 47279 Transmission Breakout. Leave the
OEM-side connected.
3. Using a DVOM at J 47279-1 Transmission
Overlay, test for wire-to-wire shorts between pin
11 and all other pins in the 20-way connector, and
shorts-to-ground between pin 11 and chassis
ground.
Value(s)
Yes
Go to Step 7
No
Go to Step 8
NOTE: The resistance value between pins 11 and
12, and between pins 11 and 17 (7-speed models)
will read normal solenoid resistance.
7
8
9
6–310
Were any opens, wire-to-wire shorts, or shorts-toground found?
1. Remove the hydraulic control module assembly.
2. Repair or replace the internal wiring harness.
Is the repair complete?
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
Refer to TCM diagnostic procedure, Section 3–6.
Is Section 3–6 complete?
In order to verify your repair:
1. Clear the DTC.
2. Drive the vehicle under conditions noted in
failure records.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Go to Step 9
Go to Step 9
Begin the
diagnosis again.
Go to Step 1
System OK
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2686 Actuator Supply Voltage 3 (HSD 3) High
END VIEW OF
20-WAY CONNECTOR
END VIEW OF
80-WAY CONNECTOR
1
6
7
10
11
14
15
20
61
80
41
60
21
40
1
20
TRANSMISSION
HSD3
TCC
SS2
TCM
11
12
17
WIRE 131
WIRE 137
WIRE 119
(7-SPEED MODELS)
31
HSD3
V BATTERY
37
19
15
RTDR ACCUM
HSD3
SS2
B
A
WIRE 131
WIRE 119
RTDR OR
DIFF LOCK (T-CASE)
HSD3
PCS5
B
A
WIRE 131
WIRE 115
V09068.00.00
Circuit Description
High Side Driver 3 (HSD3) supplies battery voltage to the TCC, PCS5 (retarder and 7-speed models) and SS2
(also, retarder and 7-speed models) solenoids via wire 131. HSD3 is continuously ON during normal operation
except during brief circuit tests. The TCM regulates control current to the solenoids by switching the appropriate
Low Side Driver (LSD) ON and OFF. DTC P2686 indicates the TCM has detected greater than or equal to 6V in
the HSD3 circuit when HSD3 is OFF during TCM initialization. DTC P2686 could be caused by an open or shortto-battery in the high side wiring attached to HSD3 (wire 131).
Conditions for Running the DTC
• The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater
than 9V and less than 32V (24V TCM).
•
HSD3 is commanded ON.
•
Engine speed greater than 200 rpm.
Copyright © 2005 General Motors Corp.
6–311
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2686 Actuator Supply Voltage 3 (HSD 3) High
Conditions for Setting the DTC
DTC P2686 is set when the TCM detects a high voltage condition (> 6V) in the HSD3 circuit after two solenoids
indicate a failure.
Actions Taken When the DTC Sets
When DTC P2686 is active, the following conditions will occur:
•
The CHECK TRANS light illuminates.
•
DTC is stored in TCM history.
•
Hydraulic default (SOL OFF) is commanded. The shift selector position and hydraulic state of latch valves
determines the range attained.
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
•
You may have to drive the vehicle in order to experience a fault. Use the data obtained from failure records to
determine transmission range and/or certain vehicle operating variables such as temperature, run time etc. This
data can be useful in reproducing the failure mode when DTC was set.
•
Inspect the wiring for poor electrical connections at the TCM and transmission connector. Look for the
following conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
•
Inspect OEM wiring harness routing, look for possible contact points where chafing could occur leading to an
open or short circuit condition. Moving parts on the vehicle could be contacting the harness; this includes
parking brake drum, suspension components, etc.
•
When diagnosing for an intermittent short or open, massage the wiring harness while watching the test
equipment for a change.
Test Description
This DTC requires the use of the J 47275 TCM Breakout and J 47279 Transmission Breakout. The numbers below
refer to step numbers on the diagnostic table.
2. This step tests for the proper ignition voltage.
3. This step tests for an active DTC.
4. This step tests for an open in wire 131 of the OEM chassis harness.
5. This step tests for wire-to-wire short, or short-to-battery in wire 131 of the OEM chassis harness.
7. This step tests for wiring defects in the transmission internal harness.
6–312
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2686 Actuator Supply Voltage 3 (HSD3) High
Step
1
2
3
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
1. Install the Allison DOC™ For PC–Service Tool. 9–18V (12V TCM)
18–32V (24V TCM)
2. Start the engine.
3. Record the failure records.
4. Monitor ignition voltage.
Is voltage within the specified values?
1. Clear the DTC.
2. Start the engine and test drive the vehicle.
3. Attempt to duplicate the same conditions
observed in the failure records (range attained,
temperature, etc.).
Yes
Go to Step 2
Go to Step 3
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Resolve voltage
problems
Go to Step 4
Go to
Diagnostic Aids
Go to Step 6
Go to Step 5
NOTE: This DTC is intended to detect an open or
short-to-battery condition in the HSD3 electrical
circuit.
4
Did DTC P2686 return?
1. Turn OFF the ignition.
2. Install the J 47275 TCM Breakout at the 80-way
connector.
3. Install J 47279 adapter at the 20-way connector.
4. Turn ON the ignition. Leave the engine OFF.
5. Using Allison DOC™ For PC–Service Tool, enter
Solenoid Test mode and command the TCC
solenoid ON.
6. Determine the voltage drop in the HSD3 circuit
as follows:
• At J 47275-1 TCM Overlay, measure voltage
between pin 31 and an isolated ground.
• At J 47279-1 Transmission Overlay, measure
voltage drop between pin 11 and an isolated
ground.
• Subtract the two voltage measurements to
obtain the voltage drop in the circuit.
NOTE: A voltage drop of more than 0.5V indicates
an excessive voltage loss in the OEM harness.
Did the high-side voltage drop exceed 0.5VDC?
Copyright © 2005 General Motors Corp.
6–313
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2686 Actuator Supply Voltage 3 (HSD3) High (cont’d)
Step
5
6
7
Action
1. Turn OFF the ignition.
2. Disconnect the TCM from the J 47275 TCM
Breakout. Leave the OEM-side connected.
3. Disconnect the OEM-side of the 20-way
connector from the J 47279 adapter. Leave the
transmission-side connected.
4. Inspect the routing of wire 131 in the chassis
harness between the TCM and the transmission
connectors.
5. At J 47275-1 TCM Overlay, test for wire-to-wire
shorts between pin 31 and all other pins in the
80-way connector.
Were any wire-to-wire shorts found?
NOTE: The vehicle OEM has responsibility for all
external wiring harness repairs. Harness repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Value(s)
Coordinate with the vehicle OEM to repair or
replace the chassis harness.
Is the repair complete?
1. Turn OFF the ignition.
2. Verify the J 47279 Transmission Breakout is
installed at the transmission 20-way connector
and the OEM-side is disconnected.
3. Using a DVOM at J 47279-1 Transmission
Overlay, test for wire-to-wire shorts between
pin 11 and all other pins in the 20-way connector.
Yes
Go to Step 6
No
Go to Step 7
Go to Step 10
Go to Step 8
Go to Step 9
NOTE: The resistance value between pins 11 and
12, and between pins 11 and 17 (7-speed models)
will read normal solenoid resistance.
8
9
10
6–314
Were any wire-to-wire shorts found?
1. Remove the hydraulic control module assembly.
2. Repair or replace the internal wiring harness.
Is the repair complete?
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
Refer to TCM diagnostic procedure, Section 3–6.
Is Section 3–6 complete?
In order to verify your repair:
1. Clear the DTC.
2. Drive the vehicle under conditions noted in
failure records.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Go to Step 10
Go to Step 10
Begin the
diagnosis again.
Go to Step 1
System OK
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2714 Pressure Control Solenoid 4 (PCS4) Stuck Off
Refer to Hydraulic Schematic
Circuit Description
The Transmission Control Module (TCM) uses input from the turbine speed and the output speed sensors to detect
if a clutch is slipping. Pressure Control Solenoid 4 (PCS4) supplies hydraulic pressure to the C4 clutch in second
and sixth ranges. The TCM sets a DTC P2714 when it detects a slip condition while PCS4 is supplying hydraulic
pressure to the oncoming clutch.
Conditions for Running the DTC
•
Hydraulic system is pressurized.
•
Output speed greater than or equal to 125 rpm.
•
Turbine speed greater than or equal to 60 rpm.
•
Cold Mode operation not required.
Conditions for Setting the DTC
DTC P2714 sets when the TCM detects an incorrect oncoming ratio (range-to-range) for an accumulated number
of occurrences.
Actions Taken When the DTC Sets
•
When DTC P2714 occurs, the TCM will command previous range.
•
While Diagnostic Response is active, the TCM ignores shift selector inputs.
•
The CHECK TRANS light illuminates.
•
DTC is stored in TCM history.
•
The TCM inhibits TCC engagement.
•
The TCM freezes shift adapts (DNA).
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
•
This DTC indicates the oncoming clutch being controlled by PCS4 is not applied or applied too slowly.
Common causes include:
— Erratic turbine or output speed signals.
— A leak or obstruction in the C4 clutch apply circuit.
— A defective solenoid.
— A stuck PCS4 regulator valve.
•
PCS4 supplies hydraulic pressure to C4 clutch in second and sixth ranges. Check the Allison DOC™ For PC–
Service Tool failure record data for previous or current range information when the DTC was set to determine
which clutch circuit is suspect.
Copyright © 2005 General Motors Corp.
6–315
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
•
If the condition is intermittent, connect Allison DOC™ For PC–Service Tool and observe the speed sensor
indicated by the code. If the signal is erratic, investigate and eliminate the following:
— Intermittent wiring connection
— Excessive vibration (driveline or engine torsionals)
— Irregular sensor gap (loose sensor, loose tone wheel, or damaged tone wheel).
Test Description
The numbers below refer to step numbers on the diagnostic table.
2. This step tests for proper transmission fluid level.
3. This step tests for active diagnostic codes.
4. This step tests ignition voltage.
5. This step tests speed sensor readings.
6. This step tests for C4 clutch pressure from PCS4.
7. This step tests for evidence of clutch failure.
8. This step tests for stuck or sticking valves and damaged valve body gaskets.
DTC P2714 Pressure Control Solenoid 4 (PCS4) Stuck Off
Step
1
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
2
Perform the Fluid Checking Procedure (refer to the
appropriate mechanic’s tips).
Is the transmission fluid level correct?
Go to Step 3
3
1.
2.
3.
4.
5.
Go to Step 4
Install the Allison DOC™ For PC–Service Tool.
Turn ON the ignition, leave engine OFF.
Record the failure records.
Clear the DTC.
Drive the vehicle. Attempt to duplicate same
operating conditions observed in failure records.
Yes
Go to Step 2
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Go to Fluid Check
Procedure
(refer to
mechanic’s tips)
Go to
Diagnostic Aids
NOTE: This DTC indicates that the TCM has
detected a slip condition and could not verify the
correct oncoming ratio following a shift.
4
5
6–316
Did DTC P2714 return?
1. Install the Allison DOC™ For PC–Service Tool. 9–18V (12V TCM)
2. Start the engine.
18–32V (24V TCM)
3. Record the DTC Failure Record data.
4. Using the Allison DOC™ For PC–Service Tool,
measure ignition voltage.
Is the voltage within the specified value?
1. Start the engine and drive the vehicle under
normal operating conditions.
2. Using Allison DOC™ For PC–Service Tool,
monitor turbine, engine, and output speed sensor
readings using the strip chart display.
Is speed sensor data erratic or are dropouts in signal
indicated?
Watch for erratic
speed sensor
signals
Copyright © 2005 General Motors Corp.
Go to Step 5
Go to General
Troubleshooting
Section 8
Go to appropriate
speed sensor DTC
Go to Step 6
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2714 Pressure Control Solenoid 4 (PCS4) Stuck Off (cont’d)
Step
6
7
8
9
10
11
Action
1. Turn OFF the ignition.
2. Install 2000 kPa (300 psi) pressure gauges in
Main and C4 pressure taps.
3. Start the engine.
4. Using Allison DOC™ For PC–Service Tool,
select the clutch test mode.
5. With brakes applied, select and attain the range
where the DTC occurred as indicated in the
failure records.
6. Read and record Main and C4 clutch pressures.
Are the pressure readings within specified values in
Appendix B?
Remove the dipstick and inspect the transmission
fluid for clutch debris or burnt odor. If necessary,
drain a small amount of fluid for this inspection.
Are there signs of a clutch failure?
1. Consult the service manual and remove the
transmission hydraulic control module.
2. Inspect the control valve bodies for stuck or
sticking solenoid regulator valves.
3. Inspect the suction filter. Be sure screen is not
plugged.
4. Inspect for damaged gaskets and face seals.
Was a valve body problem found and repaired?
Replace PCS4.
Is the replacement complete?
Value(s)
Refer to Main and
Clutch Pressure
specification in
Appendix B
Remove the main and lube filters and inspect for
clutch debris. It may also be necessary to remove the
control module and inspect the suction screen for
clutch debris.
If debris is found, remove the transmission for
overhaul or replacement (refer to the appropriate
service manual).
Is the replacement complete?
In order to verify your repair:
1. Clear the DTC.
2. Using Allison DOC™ For PC–Service Tool,
monitor engine, turbine and output speed sensor
readings.
3. Drive the vehicle under normal operating
conditions.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 7
No
Go to Step 8
Go to Step 10
Go to
Diagnostic Aids
Go to Step 11
Go to Step 9
Go to Step 11
Go to Step 11
Begin the
diagnosis again.
Go to Step 1
System OK
6–317
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2715 Pressure Control Solenoid 4 (PCS4) Stuck On
Refer to Hydraulic Schematic
Circuit Description
The Transmission Control Module (TCM) uses information from the turbine and output speed sensors to detect if a
clutch is in a tie-up condition or if three clutches are applied. Pressure Control Solenoid 4 (PCS4) supplies
hydraulic pressure to the C4 clutch in second and sixth ranges. The TCM sets a DTC P2715 when it detects a tie-up
condition while PCS4 is supplying hydraulic pressure to the off-going clutch.
Conditions for Running the DTC
• Hydraulic system is pressurized.
•
Output speed greater than or equal to 200 rpm.
•
Turbine speed greater than or equal to 200 rpm.
•
Cold Mode operation not required.
Conditions for Setting the DTC
DTC P2715 sets when the transmission is shifting from range to range and the off-going range (ratio) remains
engaged even though the off-going clutch is commanded OFF.
Actions Taken When the DTC Sets
• When DTC P2715 occurs, the TCM will command previous range.
•
While Diagnostic Response is active, the TCM ignores shift selector inputs.
•
The CHECK TRANS light illuminates.
•
DTC is stored in TCM history.
•
The TCM inhibits TCC engagement.
•
The TCM freezes shift adapts (DNA).
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
• This DTC indicates the off-coming clutch being controlled by PCS4 is not released or released too slowly.
Common causes include:
— Erratic turbine and output speed sensor readings.
— An obstruction in the C4 clutch exhaust circuit.
— A defective PCS4 solenoid.
— A stuck PCS4 regulator valve.
• PCS4 supplies hydraulic pressure to C4 clutch in second and sixth ranges. Check the Allison DOC™ For PC–
Service Tool failure record data for previous or current range information when the DTC was set to determine
which clutch circuit is suspect.
•
If the condition is intermittent, connect Allison DOC™ For PC–Service Tool and observe the speed sensor
indicated by the code. If the signal is erratic, investigate and eliminate the following:
— Intermittent wiring connection
— Excessive vibration (driveline or engine torsionals)
— Irregular sensor gap (loose sensor, loose tone wheel, or damaged tone wheel).
6–318
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
Test Description
The numbers below refer to step numbers on the diagnostic table.
2. This step tests for proper transmission fluid level.
3. This step tests for active diagnostic codes.
4. This step tests ignition voltage.
5. This step tests speed sensor readings.
6. This step tests for C4 clutch pressure from PCS4.
7. This step tests for evidence of clutch failure.
8. This step tests for stuck or sticking valves and damaged valve body gaskets.
DTC P2715 Pressure Control Solenoid 4 (PCS4) Stuck On
Step
1
2
3
Action
Was Section 3–5, Beginning The
Troubleshooting Process, performed?
Value(s)
Perform the Fluid Checking Procedure (refer to
appropriate mechanic’s tips).
Is the transmission fluid level correct?
Install the Allison DOC™ For PC–Service Tool.
1. Turn ON the ignition, leave engine OFF.
2. Record the failure records.
3. Clear the DTC.
4. Drive the vehicle. Attempt to duplicate same
operating conditions observed in failure
records.
Yes
Go to Step 2
Go to Step 3
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Go to Fluid Check
Procedure (refer to
mechanic’s tips)
Go to Step 4
Go to
Diagnostic Aids
9–18V (12V TCM)
18–32V (24V TCM)
Go to Step 5
Go to General
Troubleshooting
Section 8
Watch for erratic
speed sensor
signals
Go to appropriate
speed sensor DTC
Go to Step 6
NOTE: This DTC indicates that the TCM has
detected that the off-going clutch did not release
(clutch tie-up), following a shift.
4
5
Did DTC P2715 return?
1. Install the Allison DOC™ For PC–Service
Tool.
2. Start the engine.
3. Record the DTC Failure Record data.
4. Using the Allison DOC™ For PC–Service
Tool, measure ignition voltage.
Is the voltage within the specified value?
1. Start the engine and drive the vehicle under
normal operating conditions.
2. Using Allison DOC™ For PC–Service Tool,
monitor turbine, engine, and output speed
sensor readings using the strip chart display.
Is speed sensor data erratic or are dropouts in
signal indicated?
Copyright © 2005 General Motors Corp.
6–319
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2715 Pressure Control Solenoid 4 (PCS4) Stuck On (cont’d)
Step
6
7
8
9
10
11
6–320
Action
1. Turn OFF the ignition.
2. Install 2000 kPa (300 psi) pressure gauges in
Main and C4 pressure taps.
3. Start the engine.
4. Using Allison DOC™ For PC–Service Tool,
select the clutch test mode.
5. With brakes applied, select and attain the
range where the DTC occurred as indicated in
the failure records.
6. Read and record Main and C4 clutch
pressures.
Are the pressure readings within specified values
in Appendix B?
Remove the dipstick and inspect the transmission
fluid for clutch debris or burnt odor. If necessary,
drain a small amount of fluid for this inspection.
Are there signs of a clutch failure?
1. Consult the service manual and remove the
transmission hydraulic control module.
2. Inspect the control valve bodies for stuck or
sticking solenoid regulator valves.
3. Inspect the suction filter. Be sure screen is not
plugged.
4. Inspect for damaged gaskets and face seals.
Was a valve body problem found and repaired?
Replace PCS4.
Is the replacement complete?
Remove the main and lube filters and inspect for
clutch debris. It may also be necessary to remove
the control module and inspect the suction screen
for clutch debris.
If debris is found, remove the transmission for
overhaul or replacement (refer to the appropriate
service manual).
Is the replacement complete?
In order to verify your repair:
1. Clear the DTC.
2. Using Allison DOC™ For PC–Service Tool,
monitor engine, turbine, and output speed
sensor readings.
3. Drive the vehicle under normal operating
conditions.
Did the DTC return?
Value(s)
Refer to Main and
Clutch Pressure
specification in
Appendix B
Copyright © 2005 General Motors Corp.
Yes
Go to Step 7
No
Go to Step 8
Go to Step 10
Go to
Diagnostic Aids
Go to Step 11
Go to Step 9
Go to Step 11
Go to Step 11
Begin the
diagnosis again.
Go to Step 1
System OK
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2718 Pressure Control Solenoid 4 (PCS4) Control Circuit Open
END VIEW OF
80-WAY CONNECTOR
END VIEW OF
20-WAY CONNECTOR
1
6
7
10
11
14
15
20
61
80
41
60
21
40
1
20
TRANSMISSION
TRANSID
HSD1
PCS4
PCS6
MAIN MOD
TCM
20
1
2
7
8
WIRE 176
WIRE 111
WIRE 155
WIRE 178
WIRE 174
76
11
TRANSID
HSD1
ANALOG
INTERFACE
55
78
V BATTERY
74
V09066.00.00
Circuit Description
Pressure Control Solenoid 4 (PCS4) is a normally closed (N/C) solenoid used to apply the C4 clutch in second and
sixth ranges. The TCM commands the solenoid ON to produce hydraulic pressure in the clutch apply circuit. When
PCS4 is commanded OFF, the clutch pressure is released.
The TCM sends control current to PCS4 from High Side Driver 1 (HSD1) via wire 111. HSD1 is continuously ON
unless the TCM detects a fault condition. The TCM regulates the amount of current to PCS4 by switching PCS4
Low Side Driver (LSD) ON and OFF. Wire 155 completes the circuit between PCS4 and its LSD. DTC P2718
indicates that the TCM has detected an open condition in PCS4 electrical circuit. The open condition may exist in
the high side (wire 111) or low side (wire 155).
Conditions for Running the DTC
•
The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater
than 9V and less than 32V (24V TCM).
•
TCM initialization is in process or engine speed is greater than 200 rpm and less than 7500 rpm for 5 seconds.
Conditions for Setting the DTC
DTC P2718 is set when the TCM detects an open circuit on the PCS4 return circuit for more than 2 seconds.
Copyright © 2005 General Motors Corp.
6–321
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2718 Pressure Control Solenoid 4 (PCS4) Control Circuit Open
Actions Taken When the DTC Sets
When DTC P2718 is active, the following conditions will occur:
•
The CHECK TRANS light illuminates.
•
DTC is stored in TCM history.
•
Hydraulic default (SOL OFF) is commanded. The shift selector position and hydraulic state of latch valves
determines the range attained.
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
•
DTC P2718 indicates an open in the electrical circuit for the PCS4. In addition to PCS4, HSD1 also supplies
power to Main Mod and PCS6. If DTC P2718 is accompanied by DTC P0960 (Main Mod open circuit) and/or
P2812 (PCS6 open circuit), the open is most likely in the high side of the circuit.
•
You may have to drive the vehicle in order to experience a fault. Use the data obtained from failure records to
determine transmission range and/or certain vehicle operating variables such as temperature, run time etc. This
data can be useful in reproducing the failure mode when DTC was set.
•
Inspect the wiring for poor electrical connections at the TCM and transmission connector. Look for the
following conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
•
Inspect OEM wiring harness routing, look for possible contact points where chafing could occur leading to an
open or short circuit condition. Moving parts on the vehicle could be contacting the harness; this includes
parking brake drum, suspension components, etc.
•
When diagnosing for an intermittent short or open, massage the wiring harness while watching the test
equipment for a change.
Test Description
This DTC requires the use of the J 47275 TCM Breakout and J 47279 Transmission Breakout. The numbers below
refer to step numbers on the diagnostic table.
2. This step tests for the proper ignition voltage.
3. This step tests for an active DTC.
4. This step tests the OEM harness for an excessive voltage drop caused by an open condition in either
wire 111 or wire 155 of the OEM chassis harness.
6. This step tests for an open condition in the transmission internal harness.
7. This step tests for the proper PCS4 resistance.
6–322
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2718 Pressure Control Solenoid 4 (PCS4) Control Circuit Open
Step
1
2
3
4
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
1. Install the Allison DOC™ For PC–Service Tool. 9–18V (12V TCM)
2. Start the engine.
18–32V (24V TCM)
3. Record the failure records.
4. Monitor ignition voltage.
Is the voltage within the specified values?
1. Clear the DTC.
2. Start the engine and test drive the vehicle.
3. Attempt to duplicate the same conditions
observed in the failure records (range attained,
temperature, etc.).
NOTE: This DTC is intended to detect an open
condition in the PCS4 electrical circuit.
Did DTC P2718 return?
NOTE: Review Section 4—Wire Test Procedures
before performing steps.
1. Turn OFF the ignition.
2. Install J 47275 TCM Breakout between the OEM
external wiring harness and TCM 80-way
connectors.
3. Install J 47279 Transmission Breakout between
the OEM external wiring harness and
transmission 20-way connectors.
4. Turn ON the ignition, leave engine OFF.
5. Using Allison DOC™ For PC–Service Tool, enter
Solenoid Test mode and command PCS4 ON.
6. Determine the voltage drop in the high side of the
PCS4 circuit as follows:
• At J 47275-1 TCM Overlay, measure voltage
between pin 11 and an isolated ground.
• At J 47279-1 Transmission Overlay, measure
voltage between pin 1 and an isolated ground.
• Subtract the two voltage measurements to
obtain the voltage drop in the circuit.
7. Determine the voltage drop in the low side of the
PCS4 circuit as follows:
• At J 47275-1 TCM Overlay, measure voltage
between pin 55 and an isolated ground.
• At J 47279-1 Transmission Overlay, measure
voltage between pin 2 and an isolated ground.
• Subtract the two voltage measurements to
obtain the voltage drop in the circuit.
NOTE: A voltage drop of more than 0.5V across
either circuit indicates an excessive voltage loss in
the OEM harness.
Did either high-side or low-side voltage drop exceed
0.5VDC?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 2
Go to Step 3
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Resolve voltage
problem
Go to Step 4
Go to
Diagnostic Aids
Go to Step 5
Go to Step 6
6–323
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2718 Pressure Control Solenoid 4 (PCS4) Control Circuit Open (cont’d)
Step
5
6
7
8
9
10
11
6–324
Action
NOTE: The vehicle OEM has responsibility for all
external wiring harness repairs. Harness repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Coordinate with the vehicle OEM to repair or
replace the vehicle wiring.
Is the repair complete?
1. Turn OFF the ignition.
2. Disconnect the OEM 20-way connector from
J 47279 Transmission Breakout. Leave the
transmission 20-way connector connected to the
breakout.
3. Using a digital multimeter (DVOM), measure the
resistance between pin 1 and pin 2 of the
transmission 20-way connector.
Is the resistance within the specified value?
1. Remove the hydraulic control module assembly.
2. Disconnect PCS4 from the internal wiring
harness.
3. Using a DVOM, measure PCS4 resistance at pins
A and B.
Is resistance within the specified values?
Replace the internal wiring harness.
Is the replacement complete?
Replace PCS4.
Is the replacement complete?
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
Value(s)
Yes
Go to Step 11
No
Refer to Solenoid
Resistance Chart
(Appendix K)
Go to Step 10
Go to Step 7
Refer to Solenoid
Resistance Chart
(Appendix K)
Go to Step 8
Go to Step 9
Refer to TCM diagnostic procedure, Section 3–6.
Is Section 3–6 complete?
In order to verify your repair:
1. Clear the DTC.
2. Drive the vehicle under conditions noted in
failure records.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Go to Step 11
Go to Step 11
Go to Step 11
Begin the
diagnosis again.
Go to Step 1
System OK
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2720 Pressure Control Solenoid 4 (PCS4) Control Circuit Low
END VIEW OF
80-WAY CONNECTOR
END VIEW OF
20-WAY CONNECTOR
1
6
7
10
11
14
15
20
61
80
41
60
21
40
1
20
TRANSMISSION
TRANSID
HSD1
PCS4
PCS6
MAIN MOD
TCM
20
1
2
7
8
WIRE 176
WIRE 111
WIRE 155
WIRE 178
WIRE 174
76
11
TRANSID
HSD1
ANALOG
INTERFACE
55
78
V BATTERY
74
V09066.00.00
Circuit Description
Pressure Control Solenoid 4 (PCS4) is a normally closed (N/C) solenoid used to apply the C4 clutch in second and
sixth ranges. The TCM commands the solenoid ON to produce hydraulic pressure in the clutch apply circuit. When
PCS4 is commanded OFF, the clutch pressure is released.
The TCM sends control current to PCS4 from High Side Driver 1 (HSD1) via wire 111. HSD1 is continuously ON
unless the TCM detects a fault condition. The TCM regulates the amount of current to PCS4 by switching PCS4
Low Side Driver (LSD) ON and OFF. Wire 155 completes the circuit between PCS4 and its LSD. DTC P2720
indicates that the TCM has detected a short-to-ground condition in the low side of PCS4 electrical circuit.
Conditions for Running the DTC
•
The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater
than 9V and less than 32V (24V TCM).
•
TCM initialization is in process or engine speed is greater than 200 rpm and less than 7500 rpm for 5 seconds.
Conditions for Setting the DTC
DTC P2720 is set when the TCM detects a short-to-ground in the PCS4 return circuit for more than 2 seconds.
Copyright © 2005 General Motors Corp.
6–325
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2720 Pressure Control Solenoid 4 (PCS4) Control Circuit Low
Actions Taken When the DTC Sets
When DTC P2720 is active, the following conditions will occur:
•
The CHECK TRANS light illuminates.
•
DTC is stored in TCM history.
•
Hydraulic default (SOL OFF) is commanded. The shift selector position and hydraulic state of latch valves
determines the range attained.
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
•
DTC P2720 indicates a short-to-ground in the electrical circuit for PCS4.
•
You may have to drive the vehicle in order to experience a fault. Use the data obtained from failure records to
determine transmission range and/or certain vehicle operating variables such as temperature, run time etc. This
data can be useful in reproducing the failure mode when DTC was set.
•
Inspect the wiring for poor electrical connections at the TCM and transmission connector. Look for the
following conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
•
Inspect OEM wiring harness routing, look for possible contact points where chafing could occur leading to an
open or short circuit condition. Moving parts on the vehicle could be contacting the harness; this includes
parking brake drum, suspension components, etc.
•
When diagnosing for an intermittent short or open, massage the wiring harness while watching the test
equipment for a change.
•
Advanced Troubleshooting (requires a frequency-capable digital multimeter, if available)—measure solenoid
LSD functionality as follows:
1. Install TCM breakout harness adapter J 47275 between the 80-way connectors of the TCM and OEM
harness.
2. Set up a frequency-capable digital multimeter, e.g. Fluke 87, to monitor frequency by selecting the
VOLTS-DC scale and depressing the HERTZ button once.
3. Connect the RED test lead to the solenoid low side pin at TCM breakout harness adapter J 47275. Connect the BLACK test lead to the isolated ground pin.
4. Use Allison DOC™ For PC–Service Tool solenoid test function to command the solenoid ON and OFF.
5. Frequency should read in the KILOHERTZ range when the driver is commanded ON. Frequency should
read 0 hertz when the driver is commanded OFF.
6–326
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
Test Description
This DTC requires the use of the J 47279—3000 and 4000 Product Families Transmission Breakout Harness. The
numbers below refer to step numbers on the diagnostic table.
2. This step tests for the proper ignition voltage.
3. This step tests for an active DTC.
4. This step tests for wire-to-wire shorts or a short-to-ground condition in wire 155.
6. This step tests for the wire-to-wire shorts or a short-to-ground in the internal transmission harness.
DTC P2720 Pressure Control Solenoid 4 (PCS4) Control Circuit Low
Step
1
2
3
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
1. Install the Allison DOC™ For PC–Service Tool. 9–18V (12V TCM)
18–32V (24V TCM)
2. Start the engine.
3. Record the failure records.
4. Monitor ignition voltage.
Is the voltage within the specified values?
1. Clear the DTC.
2. Start the engine and test drive the vehicle.
3. Attempt to duplicate the same conditions
observed in the failure records (range attained,
temperature, etc.).
Yes
Go to Step 2
Go to Step 3
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Resolve voltage
problem
Go to Step 4
Go to
Diagnostic Aids
Go to Step 5
Go to Step 6
NOTE: This DTC is intended to detect a short-toground condition in the PCS4 electrical circuit.
4
Did DTC P2720 return?
NOTE: Review Section 4—Wire Test Procedures
before performing steps.
1. Turn OFF the ignition.
2. Disconnect the TCM 80-way connector.
3. Install the OEM-side of the 80-way connector to
the J 47275 harness. Leave the TCM
disconnected.
4. Disconnect the transmission 20-way connector.
5. Inspect the routing of wire 155 in the chassis
harness between the TCM and the transmission
connector.
6. At J 47275-1 TCM Overlay, test for wire-to-wire
shorts between pin 55 and all other pins in the
80-way connector, and shorts-to-ground between
pin 55 and chassis ground.
Were any wire-to-wire shorts or shorts-to-ground
wiring defects found?
Copyright © 2005 General Motors Corp.
6–327
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2720 Pressure Control Solenoid 4 (PCS4) Control Circuit Low (cont’d)
Step
5
6
Action
NOTE: The vehicle OEM has responsibility for all
external wiring harness repairs. Harness repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Coordinate with the vehicle OEM to repair or
replace the vehicle wiring.
Is the repair complete?
1. Turn OFF the ignition.
2. Install J 47279 Transmission Breakout to the
transmission 20-way connector. Leave the OEM
harness disconnected.
3. Using a DVOM, test for wire-to-wire shorts
between pin 2 and all other pins in the 20-way
connector, and shorts-to-ground between pin 2
and chassis ground.
Value(s)
Yes
Go to Step 11
No
Refer to Solenoid
Resistance Chart
(Appendix K)
Go to Step 7
Go to Step 10
Go to Step 8
Go to Step 9
NOTE: The resistance value between pins 2 and 1,
and between pins 2 and 20 will read normal
solenoid resistance. The resistance value between
pins 2 and 7 (7-speed models), and between pins 2
and 8 will be twice normal solenoid resistance.
Refer to the Solenoid Resistance chart for these
values.
7
8
9
10
11
6–328
Were any wire-to-wire shorts or shorts -to-ground
found?
1. Remove the hydraulic control module assembly.
2. Inspect the internal harness for wire-to-wire
shorts or shorts-to-ground.
3. Were wire-to-wire shorts or shorts-to-ground
found?
Replace the internal wiring harness.
Is the replacement complete?
Replace PCS4.
Is the replacement complete?
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
Refer to TCM diagnostic procedure, Section 3–6.
Is Section 3–6 complete?
In order to verify your repair:
1. Clear the DTC.
2. Drive the vehicle under conditions noted in
failure records.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Go to Step 11
Go to Step 11
Go to Step 11
Begin the
diagnosis again.
Go to Step 1
System OK
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2721 Pressure Control Solenoid 4 (PCS4) Control Circuit High
END VIEW OF
80-WAY CONNECTOR
END VIEW OF
20-WAY CONNECTOR
1
6
7
10
11
14
15
20
61
80
41
60
21
40
1
20
TRANSMISSION
TRANSID
HSD1
PCS4
PCS6
MAIN MOD
TCM
20
1
2
7
8
WIRE 176
WIRE 111
WIRE 155
WIRE 178
WIRE 174
76
11
TRANSID
HSD1
ANALOG
INTERFACE
55
78
V BATTERY
74
V09066.00.00
Circuit Description
Pressure Control Solenoid 4 (PCS4) is a normally closed (N/C) solenoid used to apply the C4 clutch in second and
sixth ranges. The TCM commands the solenoid ON to produce hydraulic pressure in the clutch apply circuit. When
PCS4 is commanded OFF, the clutch pressure is released.
The TCM sends control current to PCS4 from High Side Driver 1 (HSD1) via wire 111. HSD1 is continuously ON
unless the TCM detects a fault condition. The TCM regulates the amount of current to PCS4 by switching PCS4
Low Side Driver (LSD) ON and OFF. Wire 155 completes the circuit between PCS4 and its LSD. DTC P2721
indicates that the TCM has detected a short-to-battery condition in the low side of PCS4 electrical circuit.
Conditions for Running the DTC
•
The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater
than 9V and less than 32V (24V TCM).
•
TCM initialization is in process or engine speed is greater than 200 rpm and less than 7500 rpm for 5 seconds.
Conditions for Setting the DTC
DTC P2721 is set when the TCM detects a short-to-battery in the PCS4 return circuit for more than 2 seconds.
Copyright © 2005 General Motors Corp.
6–329
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2721 Pressure Control Solenoid 4 (PCS4) Control Circuit High
Actions Taken When the DTC Sets
When DTC P2721 is active, the following conditions will occur:
•
The CHECK TRANS light illuminates.
•
DTC is stored in TCM history.
•
Hydraulic default (SOL OFF) is commanded. The shift selector position and hydraulic state of latch valves
determines the range attained.
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
•
DTC P2721 indicates a short-to-battery in the electrical circuit for the PCS4 solenoid.
•
You may have to drive the vehicle in order to experience a fault. Use the data obtained from failure records to
determine transmission range and/or certain vehicle operating variables such as temperature, run time etc. This
data can be useful in reproducing the failure mode when DTC was set.
•
Inspect the wiring for poor electrical connections at the TCM and transmission connector. Look for the
following conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
•
Inspect OEM wiring harness routing, look for possible contact points where chafing could occur leading to an
open or short circuit condition. Moving parts on the vehicle could be contacting the harness; this includes
parking brake drum, suspension components, etc.
•
When diagnosing for an intermittent short or open, massage the wiring harness while watching the test
equipment for a change.
•
Advanced Troubleshooting (requires a frequency-capable digital multimeter, if available)—measure solenoid
LSD functionality as follows:
1. Install TCM breakout harness adapter J 47275 between the 80-way connectors of the TCM and OEM
harness.
2. Set up a frequency-capable digital multimeter, e.g. Fluke 87, to monitor frequency by selecting the
VOLTS-DC scale and depressing the HERTZ button once.
3. Connect the RED test lead to the solenoid low side pin at TCM breakout harness adapter J 47275. Connect the BLACK test lead to the isolated ground pin.
4. Use Allison DOC™ For PC–Service Tool solenoid test function to command the solenoid ON and OFF.
5. Frequency should read in the KILOHERTZ range when the driver is commanded ON. Frequency should
read 0 hertz when the driver is commanded OFF.
6–330
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
Test Description
This DTC requires the use of the J 47275 TCM Breakout and J 47279 Transmission Breakout. The numbers below
refer to step numbers on the diagnostic table.
2. This step tests for the proper ignition voltage.
3. This step tests for an active DTC.
4. This step tests for wire-to-wire shorts between wire 155 and other wires in the OEM chassis harness.
6. This step tests for the wire-to-wire shorts in the transmission internal harness.
DTC P2721 Pressure Control Solenoid 4 (PCS4) Control Circuit High
Step
1
2
3
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
1. Install the Allison DOC™ For PC–Service Tool. 9–18V (12V TCM)
18–32V (24V TCM)
2. Start the engine.
3. Record the failure records.
4. Monitor ignition voltage.
Is voltage within specified values?
1. Clear the DTC.
2. Start the engine and test drive the vehicle.
3. Attempt to duplicate the same conditions
observed in the failure records (range attained,
temperature, etc.).
Yes
Go to Step 2
Go to Step 3
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Resolve voltage
problem
Go to Step 4
Go to
Diagnostic Aids
Go to Step 5
Go to Step 6
NOTE: This DTC is intended to detect a short-tobattery condition in the PCS4 electrical circuit.
4
Did DTC P2721 return?
NOTE: Review Section 4—Wire Test Procedures
before performing steps.
1. Turn OFF the ignition.
2. Disconnect the TCM 80-way connector.
3. Install the OEM-side of the 80-way connector to
the J 47275 TCM Breakout. Leave the TCM-side
disconnected.
4. Disconnect the transmission 20-way connector.
5. Inspect the routing of wire 111 in the chassis
harness between the TCM and the transmission
connector.
6. At J 47275-1 TCM Overlay, test for wire-to-wire
shorts between pin 55 and all other pins in the
80-way connector.
Were any wire-to-wire shorts found?
Copyright © 2005 General Motors Corp.
6–331
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2721 Pressure Control Solenoid 4 (PCS4) Control Circuit High (cont’d)
Step
5
6
Action
NOTE: The vehicle OEM has responsibility for all
external wiring harness repairs. Harness repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Coordinate with the vehicle OEM to repair or
replace the chassis harness.
Is the repair complete?
1. Turn OFF the ignition.
2. Install J 47279 Transmission Breakout to the
transmission 20-way connector. Leave the OEM
harness disconnected.
3. Using a DVOM, test for wire-to-wire shorts
between pin 2 and all other pins in the 20-way
connector.
Value(s)
Yes
Go to Step 11
No
Refer to Solenoid
Resistance Chart
(Appendix K)
Go to Step 7
Go to Step 10
Go to Step 8
Go to Step 9
NOTE: The resistance value between pins 2 and 1,
and between pins 2 and 20 will read normal
solenoid resistance. The resistance value between
pins 2 and 7 (7-speed models), and between pins 2
and 8 will be twice normal solenoid resistance.
Refer to the Solenoid Resistance chart for these
values.
7
8
9
10
11
6–332
Were any wire-to-wire shorts found?
1. Remove the hydraulic control module assembly.
2. Inspect the internal harness for wire-to-wire
shorts.
Were any wire-to-wire shorts found?
Repair or replace the internal wiring harness.
Is the repair complete?
Replace PCS4.
Is the replacement complete?
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
Refer to TCM diagnostic procedure, Section 3–6.
Is Section 3–6 complete?
In order to verify your repair:
1. Clear the DTC.
2. Drive the vehicle under normal operating
conditions.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Go to Step 11
Go to Step 11
Go to Step 11
Begin the
diagnosis again.
Go to Step 1
System OK
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2723 Pressure Control Solenoid 1 (PCS1) Stuck Off
Refer to Hydraulic Schematic
Circuit Description
The Transmission Control Module (TCM) uses input from the turbine speed and the output speed sensors to detect
if a clutch is slipping. Pressure Control Solenoid 1 (PCS1) supplies hydraulic pressure to the C1 clutch in first
range through fourth range. The TCM sets a DTC P2723 when it detects a slip condition while PCS1 is supplying
hydraulic pressure to the oncoming clutch.
Conditions for Running the DTC
• Hydraulic system is pressurized.
• Output speed greater than or equal to 125 rpm.
• Turbine speed greater than or equal to 60 rpm.
• Cold Mode operation not required.
Conditions for Setting the DTC
DTC P2723 sets when the TCM detects an incorrect oncoming ratio (range-to-range) for an accumulated number
of occurrences.
Actions Taken When the DTC Sets
• When DTC P2723 occurs, the TCM will command previous range.
• While Diagnostic Response is active, the TCM ignores shift selector inputs.
• The CHECK TRANS light illuminates.
• DTC is stored in TCM history.
• The TCM inhibits TCC engagement.
• The TCM freezes shift adapts (DNA).
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
• This DTC indicates the oncoming clutch being controlled by PCS1 is not applied or applied too slowly.
Common causes include:
— Erratic turbine or output speed signals.
— A leak or obstruction in a specific clutch apply circuit.
— A defective solenoid. PCS1 and SS1 each receive commands from the TCM during a shift to Drive. A
failure of either solenoid or related hydraulic circuit can cause a DTC P2723.
— A stuck PCS1 regulator valve.
— A stuck C1 logic latch valve.
• PCS1 supplies hydraulic pressure to C1 clutch in first range through fourth ranges. Check the Allison DOC™
For PC–Service Tool failure record data for previous or current range information when the DTC was set to
determine which clutch circuit is suspect.
•
If the condition is intermittent, connect Allison DOC™ For PC–Service Tool and observe the speed sensor
indicated by the DTC. If the signal is erratic, investigate and eliminate the following:
— Intermittent wiring connection
— Excessive vibration (driveline or engine torsionals)
— Irregular sensor gap (loose sensor, loose tone wheel, or damaged tone wheel).
Copyright © 2005 General Motors Corp.
6–333
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
Test Description
The numbers below refer to step numbers on the diagnostic table.
2. This step tests for proper transmission fluid level.
3. This step tests for active diagnostic codes.
4. This step tests ignition voltage.
5. This step tests speed sensor readings.
6. This step tests for C1 clutch pressure from PCS1.
7. This step tests for evidence of clutch failure.
8. This step tests for stuck or sticking valves and damaged valve body gaskets.
DTC P2723 Pressure Control Solenoid 1 (PCS1) Stuck Off
Step
1
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
2
Perform the Fluid Checking Procedure (refer to
appropriate mechanic’s tips).
Is the transmission fluid level correct?
1. Install the Allison DOC™ For PC–Service Tool.
2. Turn ON the ignition, leave engine OFF.
3. Record the failure records.
4. Clear the DTC.
5. Drive the vehicle. Attempt to duplicate same
operating conditions observed in failure records.
3
Value(s)
Yes
Go to Step 2
Go to Step 3
Go to Step 4
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Go to Fluid Check
Procedure (refer to
mechanic’s tips)
Go to
Diagnostic Aids
NOTE: This DTC indicates that the TCM has
detected a slip condition and could not verify the
correct oncoming ratio following a shift.
4
5
6–334
Did DTC P2723 return?
1. Install the Allison DOC™ For PC–Service Tool. 9–18V (12V TCM)
Go to Step 5
18–32V (24V TCM)
2. Start the engine.
3. Record the DTC Failure Record data.
4. Using the Allison DOC™ For PC–Service Tool,
measure ignition voltage.
Is the voltage within the specified value?
Watch for erratic Go to appropriate
1. Start the engine and drive the vehicle under
normal operating conditions.
speed sensor DTC
speed sensor
2. Using Allison DOC™ For PC–Service Tool,
signals
monitor turbine, engine, and output speed sensor
readings using the strip chart display.
Is speed sensor data erratic or are dropouts in signal
indicated?
Copyright © 2005 General Motors Corp.
Go to General
Troubleshooting
(Section 7)
Go to Step 6
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2723 Pressure Control Solenoid 1 (PCS1) Stuck Off (cont’d)
Step
6
7
8
9
10
11
Action
1. Turn OFF the ignition.
2. Install 2000 kPa (300 psi) pressure gauges in
main and C1 pressure taps.
3. Start the engine.
4. Using Allison DOC™ For PC–Service Tool,
select the clutch test mode.
5. With brakes applied, select and attain the range
where the DTC occurred as indicated in the
Failure Records.
6. Read and record Main and C1 clutch pressures.
Are the pressure readings within specified values in
Appendix B?
Remove the dipstick and inspect the transmission
fluid for clutch debris or burnt odor. If necessary,
drain a small amount of fluid for this inspection.
Are there signs of a clutch failure?
1. Consult the service manual and remove the
transmission hydraulic control module.
2. Inspect the control valve bodies for stuck or
sticking solenoid regulator valves and logic latch
valves.
3. Inspect the suction filter. Be sure screen is not
plugged.
4. Inspect for damaged gaskets and face seals.
5. Be sure the C1 latch valve is not sticking. The
valve should drop freely into its bore.
Was a valve body problem found and repaired?
Consult Allison DOC™ For PC–Service Tool failure
record data. Replace PCS1 and/or SS1 based on the
following:
• DTC P2723 logged during neutral-to-drive
and/or reverse-to-drive shifts only—replace
both PCS1 and SS1.
• DTC P2723 logged during fifth-to-fourth
range shifts—replace PCS1 only.
Is the replacement complete?
Remove the main and lube filters and inspect for
clutch debris. It may also be necessary to remove the
control module and inspect the suction screen for
clutch debris.
If debris is found, remove the transmission for
overhaul or replacement (refer to the appropriate
service manual).
Is the replacement complete?
In order to verify your repair:
1. Clear the DTC.
2. Using Allison DOC™ For PC–Service Tool,
monitor engine, turbine, and output speed sensor
readings.
3. Drive the vehicle under normal operating
conditions.
Did the DTC return?
Value(s)
Refer to Main and
Clutch Pressure
specifications in
Appendix B
Copyright © 2005 General Motors Corp.
Yes
Go to Step 7
No
Go to Step 8
Go to Step 10
Go to
Diagnostic Aids
Go to Step 11
Go to Step 9
Go to Step 11
Go to Step 11
Begin the
diagnosis again.
Go to Step 1
System OK
6–335
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2724 Pressure Control Solenoid 1 (PCS1) Stuck On
Refer to Hydraulic Schematic
Circuit Description
The Transmission Control Module (TCM) uses information from the turbine and output speed sensors to detect if a
clutch is in a tie-up condition or if three clutches are applied. Pressure Control Solenoid 1 (PCS1) supplies
hydraulic pressure to the C1 clutch in first through fourth ranges. The TCM sets a DTC P2724 when it detects a tieup condition while PCS1 is supplying hydraulic pressure to the off-going clutch.
Conditions for Running the DTC
•
Hydraulic system is pressurized.
•
Output speed greater than or equal to 200 rpm.
•
Turbine speed greater than or equal to 200 rpm.
•
Cold Mode operation not required.
Conditions for Setting the DTC
DTC P2724 sets when the transmission is shifting from range to range and the off-going range (ratio) remains
engaged even though the off-going clutch is commanded OFF.
Actions Taken When the DTC Sets
•
When DTC P2724 occurs, the TCM will command previous range.
•
While Diagnostic Response is active, the TCM ignores shift selector inputs.
•
The CHECK TRANS light illuminates.
•
DTC is stored in TCM history.
•
The TCM inhibits TCC engagement.
•
The TCM freezes shift adapts (DNA).
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
•
This DTC indicates the off-coming clutch being controlled by PCS1 is not released or released too slowly.
Common causes include:
— An obstruction in the C1 clutch exhaust circuit.
— A defective PCS1 solenoid.
— A stuck PCS1 regulator valve.
•
PCS1 supplies hydraulic pressure to C1 clutch in first range through fourth ranges. Check the Allison DOC™
For PC–Service Tool failure record data for previous or current range information when the DTC was set to
determine which clutch circuit is suspect.
•
PCS1 and PCS2 are “normally high” solenoids. PCS1 and PCS2 supply full hydraulic pressure when their coils
are de-energized, and no output pressure when receiving maximum current from the TCM.
6–336
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
•
If the condition is intermittent, connect Allison DOC™ diagnostic tool and observe the speed sensor indicated
by the code. If the signal is erratic, investigate and eliminate the following:
— Intermittent wiring connection
— Excessive vibration (driveline or engine torsionals)
— Irregular sensor gap (loose sensor, loose tone wheel, or damaged tone wheel).
Test Description
The numbers below refer to step numbers on the diagnostic table.
2. This step tests for proper transmission fluid level.
3. This step tests for active diagnostic codes.
4. This step tests ignition voltage.
5. This step tests speed sensor readings.
6. This step tests for C1 clutch pressure from PCS1.
7. This step tests for evidence of clutch failure.
8. This step tests for stuck or sticking valves and damaged valve body gaskets.
DTC P2724 Pressure Control Solenoid 1 (PCS1) Stuck On
Step
1
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
2
Perform the Fluid Checking Procedure (refer to
appropriate mechanic’s tips).
Is the transmission fluid level correct?
1. Install the Allison DOC™ For PC–Service Tool.
2. Turn ON the ignition, leave engine OFF.
3. Record the failure records.
4. Clear the DTC.
5. Drive the vehicle. Attempt to duplicate same
operating conditions observed in failure records.
3
Value(s)
Yes
Go to Step 2
Go to Step 3
Go to Step 4
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Go to Fluid Check
Procedure (refer to
mechanic’s tips)
Go to
Diagnostic Aids
NOTE: This DTC indicates that the TCM has
detected that the off-going clutch did not release
(clutch tie-up) following a shift.
4
5
Did DTC P2724 return?
1. Install the Allison DOC™ For PC–Service Tool. 9–18V (12V TCM)
Go to Step 5
18–32V
(24V
TCM)
2. Start the engine.
3. Record the DTC Failure Record data.
4. Using the Allison DOC™ For PC–Service Tool,
measure ignition voltage.
Is the voltage within the specified value?
1. Start the engine and drive the vehicle under
Watch for erratic Go to appropriate
normal operating conditions.
speed sensor DTC
speed sensor
2. Using Allison DOC™ For PC–Service Tool,
signals
monitor turbine, engine, and output speed sensor
readings using the strip chart display.
Is speed sensor data erratic or are dropouts in signal
indicated?
Copyright © 2005 General Motors Corp.
Go to General
Troubleshooting
(Section 7)
Go to Step 6
6–337
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2724 Pressure Control Solenoid 1 (PCS1) Stuck On (cont’d)
Step
6
7
8
9
10
11
Action
1. Turn OFF the ignition.
2. Install 2000 kPa (300 psi) pressure gauges in
main and C1 pressure taps.
3. Start the engine.
4. Using Allison DOC™ For PC–Service Tool,
select the clutch test mode.
5. With brakes applied, select and attain the range
where the DTC occurred as indicated in the
failure records.
6. Read and record Main and C1 clutch pressures.
Are the pressure readings within specified values in
Appendix B?
Remove the dipstick and inspect the transmission
fluid for clutch debris or burnt odor. If necessary,
drain a small amount of fluid for this inspection.
Are there signs of a clutch failure?
1. Consult the service manual and remove the
transmission hydraulic control module.
2. Inspect the control valve bodies for stuck or
sticking solenoid regulator valves and logic latch
valves.
3. Inspect the suction filter. Be sure screen is not
plugged.
4. Inspect for damaged gaskets and face seals.
Was a valve body problem found and repaired?
Replace PCS1.
Is the replacement complete?
Remove the main and lube filters and inspect for
clutch debris. It may also be necessary to remove the
control module and inspect the suction screen for
clutch debris.
If debris is found, remove the transmission for
overhaul or replacement (refer to the appropriate
service manual).
Is the replacement complete?
In order to verify your repair:
1. Clear the DTC.
2. Using Allison DOC™ For PC–Service Tool,
monitor engine, turbine, and output speed sensor
readings.
3. Drive the vehicle under normal operating
conditions.
Value(s)
Refer to Main and
Clutch Pressure
specifications in
Appendix B
Did the DTC return?
6–338
Copyright © 2005 General Motors Corp.
Yes
Go to Step 7
No
Go to Step 8
Go to Step 10
Go to
Diagnostic Aids
Go to Step 11
Go to Step 9
Go to Step 11
Go to Step 11
Begin the
diagnosis again.
Go to Step 1
System OK
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2727 Pressure Control Solenoid 1 (PCS1) Control Circuit Open
END VIEW OF
80-WAY CONNECTOR
END VIEW OF
20-WAY CONNECTOR
1
6
7
10
11
14
15
20
61
80
41
60
21
40
1
20
TRANSMISSION
HSD2
PCS1
PCS2
PCS3
SS1
TCM
6
4
5
9
10
WIRE 171
WIRE 136
WIRE 152
WIRE 133
WIRE 151
71
HSD2
V BATTERY
36
52
33
51
V09067.00.00
Circuit Description
Pressure Control Solenoid 1 (PCS1) is a normally open (N/O) solenoid used to apply the C1 clutch in first through
fourth range. The TCM commands the solenoid OFF to produce hydraulic pressure in the clutch apply circuit.
When PCS1 is commanded ON, the C1 clutch is released.
The TCM sends control current to PCS1 from High Side Driver 2 (HSD2) via wire 171. HSD2 is continuously ON
unless the TCM detects a fault condition. The TCM regulates the amount of current to PCS1 by switching PCS1
Low Side Driver (LSD) ON and OFF. Wire 136 completes the circuit between PCS1 and its LSD. DTC P2727
indicates that the TCM has detected an open condition in PCS1 electrical circuit. The open condition may exist in
the high side (wire 171) or low side (wire 136).
Conditions for Running the DTC
•
The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater
than 9V and less than 32V (24V TCM).
•
TCM initialization is in process or engine speed is greater than 200 rpm and less than 7500 rpm for 5 seconds.
Conditions for Setting the DTC
DTC P2727 is set when the TCM detects an open circuit on the PCS1 return circuit for more than 2 seconds.
Copyright © 2005 General Motors Corp.
6–339
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2727 Pressure Control Solenoid 1 (PCS1) Control Circuit Open
Actions Taken When the DTC Sets
When DTC P2727 is active, the following conditions will occur:
•
The CHECK TRANS light illuminates.
•
DTC is stored in TCM history.
•
Hydraulic default (SOL OFF) is commanded. The shift selector position and hydraulic state of latch valves
determines the range attained.
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
•
DTC P2727 indicates an open in the electrical circuit for PCS1. In addition to PCS1, HSD2 also supplies
power to PCS2, PCS3, and SS1. If DTC P2727 is accompanied by DTC P0964 (PCS2 open circuit) and/or
DTC P0968 (PCS3 open circuit), the open is most likely in the high side of the circuit.
•
You may have to drive the vehicle in order to experience a fault. Use the data obtained from failure records to
determine transmission range and/or certain vehicle operating variables such as temperature, run time etc. This
data can be useful in reproducing the failure mode when DTC was set.
•
Inspect the wiring for poor electrical connections at the TCM and transmission connector. Look for the
following conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
•
Inspect OEM wiring harness routing, look for possible contact points where chafing could occur leading to an
open or short circuit condition. Moving parts on the vehicle could be contacting the harness; this includes
parking brake drum, suspension components, etc.
•
When diagnosing for an intermittent short or open, massage the wiring harness while watching the test
equipment for a change.
Test Description
This DTC requires the use of the J 47275 TCM Breakout and J 47279 Transmission Breakout. The numbers below
refer to step numbers on the diagnostic table.
2. This step tests for the proper ignition voltage.
3. This step tests for an active DTC.
4. This step tests the OEM harness for an excessive voltage drop caused by an open condition in either wire
171 or wire 136 of the OEM chassis harness.
6. This step tests for an open condition in the transmission internal harness.
7. This step tests for the proper PCS1 resistance.
6–340
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2727 Pressure Control Solenoid 1 (PCS1) Control Circuit Open
Step
1
2
3
4
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
1. Install the Allison DOC™ For PC–Service Tool. 9–18V (12V TCM)
18–32V (24V TCM)
2. Start the engine.
3. Record the failure records.
4. Monitor ignition voltage.
Is the voltage within the specified values?
1. Clear the DTC.
2. Start the engine and test drive the vehicle.
3. Attempt to duplicate the same conditions
observed in the failure records (range attained,
temperature, etc.).
NOTE: This DTC is intended to detect an open
condition in the PCS1 electrical circuit.
Did DTC P2727 return?
NOTE: Review Section 4—Wire Test Procedures
before performing steps.
1. Turn OFF the ignition.
2. Install J 47275 TCM Breakout between the OEM
and TCM 80-way connectors.
3. Install J 47279 Transmission Breakout between
the OEM and transmission 20-way connectors.
4. Turn ON the ignition, leave engine OFF.
5. Using Allison DOC™ For PC–Service Tool, enter
Solenoid Test mode and command PCS1 ON.
6. Determine the voltage drop in the high side of the
PCS1 circuit as follows:
• At J 47275-1 TCM Overlay, measure voltage
between pin 71 and an isolated ground.
• At J 47279-1 Transmission Overlay, measure
voltage between pin 6 and isolated ground.
• Subtract the two voltage measurements to
obtain the voltage drop in the circuit.
7. Determine the voltage drop in the low side of the
PCS1 circuit as follows:
• At J 47275-1 TCM Overlay, measure voltage
between pin 36 and an isolated ground.
• At J 47279-1 Transmission Overlay, measure
voltage between pin 4 and isolated ground.
• Subtract the two voltage measurements to
obtain the voltage drop in the circuit.
NOTE: A voltage drop of more than 0.5V across
either circuit indicates an excessive voltage loss in
the OEM harness.
Did either high-side or low-side voltage drop exceed
0.5VDC?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 2
Go to Step 3
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Resolve voltage
problem
Go to Step 4
Go to
Diagnostic Aids
Go to Step 5
Go to Step 6
6–341
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2727 Pressure Control Solenoid 1 (PCS1) Control Circuit Open (cont’d)
Step
5
6
7
8
9
10
11
6–342
Action
NOTE: The vehicle OEM has responsibility for all
external wiring harness repairs. Harness repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Coordinate with the vehicle OEM to repair or
replace the vehicle wiring.
Is the repair complete?
1. Turn OFF the ignition.
2. Disconnect the OEM 20-way connector from
J 47279 Transmission Breakout. Leave the
transmission 20-way connector connected to
breakout.
3. Using a digital multimeter (DVOM), measure the
resistance between pin 4 and pin 6 of the
transmission 20-way connector.
Is the resistance within the specified value?
1. Remove the hydraulic control module assembly.
2. Disconnect PCS1 from the internal wiring
harness.
3. Using a DVOM, measure PCS1 resistance at pins
A and B.
Is resistance within the specified values?
Replace the internal wiring harness.
Is the replacement complete?
Replace PCS1.
Is the replacement complete?
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
Value(s)
Yes
Go to Step 11
No
Refer to Solenoid
Resistance Chart
(Appendix K)
Go to Step 10
Go to Step 7
Refer to Solenoid
Resistance Chart
(Appendix K)
Go to Step 8
Go to Step 9
Refer to TCM diagnostic procedure, Section 3–6.
Is Section 3–6 complete?
In order to verify your repair:
1. Clear the DTC.
2. Drive the vehicle under conditions noted in
failure records.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Go to Step 11
Go to Step 11
Go to Step 11
Begin the
diagnosis again.
Go to Step 1
System OK
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2729 Pressure Control Solenoid 1 (PCS1) Control Circuit Low
END VIEW OF
80-WAY CONNECTOR
END VIEW OF
20-WAY CONNECTOR
1
6
7
10
11
14
15
20
61
80
41
60
21
40
1
20
TRANSMISSION
TCM
HSD2
6
PCS1
4
PCS2
5
PCS3
SS1
9
10
WIRE 171
WIRE 136
WIRE 152
WIRE 133
WIRE 151
71
HSD2
V BATTERY
36
52
33
51
V09067.00.00
Circuit Description
Pressure Control Solenoid 1 (PCS1) is a normally open (N/O) solenoid used to apply the C1 clutch in first through
fourth range. The TCM commands the solenoid OFF to produce hydraulic pressure in the clutch apply circuit.
When PCS1 is commanded ON, the C1 clutch is released.
The TCM sends control current to PCS1 from High Side Driver 2 (HSD2) via wire 171. HSD2 is continuously ON
unless the TCM detects a fault condition. The TCM regulates the amount of current to PCS1 by switching PCS1
Low Side Driver (LSD) ON and OFF. Wire 136 completes the circuit between PCS1 and its LSD. DTC P2729
indicates that the TCM has detected a short-to-ground condition in the low side of PCS1 electrical circuit.
Conditions for Running the DTC
• The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater
than 9V and less than 32V (24V TCM).
• TCM initialization is in process or engine speed is greater than 200 rpm and less than 7500 rpm for 5 seconds.
Conditions for Setting the DTC
DTC P2729 is set when the TCM detects a short-to-ground in the PCS1 return circuit for more than 2 seconds.
Actions Taken When the DTC Sets
When DTC P2729 is active, the following conditions will occur:
• The CHECK TRANS light illuminates.
• DTC is stored in TCM history.
• Hydraulic default (SOL OFF) is commanded. The shift selector position and hydraulic state of latch valves
determines the range attained.
Copyright © 2005 General Motors Corp.
6–343
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2729 Pressure Control Solenoid 1 (PCS1) Control Circuit Low
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
•
DTC P2729 indicates a short-to-ground in the electrical circuit for PCS1.
•
You may have to drive the vehicle in order to experience a fault. Use the data obtained from failure records to
determine transmission range and/or certain vehicle operating variables such as temperature, run time etc. This
data can be useful in reproducing the failure mode when DTC was set.
•
Inspect the wiring for poor electrical connections at the TCM and transmission connector. Look for the
following conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
•
Inspect OEM wiring harness routing, look for possible contact points where chafing could occur leading to an
open or short circuit condition. Moving parts on the vehicle could be contacting the harness; this includes
parking brake drum, suspension components, etc.
•
When diagnosing for an intermittent short or open, massage the wiring harness while watching the test
equipment for a change.
•
Advanced Troubleshooting (requires a frequency-capable digital multimeter, if available)—measure solenoid
LSD functionality as follows:
1. Install TCM breakout harness adapter J 47275 between the 80-way connectors of the TCM and OEM
harness.
2. Set up a frequency-capable digital multimeter, e.g. Fluke 87, to monitor frequency by selecting the
VOLTS-DC scale and depressing the HERTZ button once.
3. Connect the RED test lead to the solenoid low side pin at TCM breakout harness adapter J 47275. Connect the BLACK test lead to the isolated ground pin.
4. Use Allison DOC™ For PC–Service Tool solenoid test function to command the solenoid ON and OFF.
5. Frequency should read in the KILOHERTZ range when the driver is commanded ON. Frequency should
read 0 hertz when the driver is commanded OFF.
Test Description
This DTC requires the use of the J 47275 TCM Breakout and J 47279 Transmission Breakout. The numbers below
refer to step numbers on the diagnostic table.
2. This step tests for the proper ignition voltage.
3. This step tests for an active DTC.
4. This step tests for wire-to-wire shorts or a short-to-ground condition in wire 136.
6. This step tests for the wire-to-wire shorts or a short-to-ground in the internal transmission harness.
6–344
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2729 Pressure Control Solenoid 1 (PCS1) Control Circuit Low
Step
1
2
3
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
1. Install the Allison DOC™ For PC–Service Tool. 9–18V (12V TCM)
18–32V (24V TCM)
2. Start the engine.
3. Record the failure records.
4. Monitor ignition voltage.
Is the voltage within the specified values?
1. Clear the DTC.
2. Start the engine and test drive the vehicle.
3. Attempt to duplicate the same conditions
observed in the failure records (range attained,
temperature, etc.).
Yes
Go to Step 2
Go to Step 3
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Resolve voltage
problem.
Go to Step 4
Go to
Diagnostic Aids
Go to Step 5
Go to Step 6
NOTE: This DTC is intended to detect short-toground condition in the PCS1 electrical circuit.
4
5
Did DTC P2729 return?
NOTE: Review Section 4—Wire Test Procedures
before performing steps.
1. Turn OFF the ignition.
2. Disconnect the TCM 80-way connector.
3. Install the OEM-side of the 80-way connector to
the J 47275 TCM Breakout. Leave the TCM
disconnected.
4. Disconnect the transmission 20-way connector.
5. Inspect the routing of wire 136 in the chassis
harness between the TCM and the transmission
connector.
6. At J 47275-1 TCM Overlay, test for wire-to-wire
shorts between pin 36 and all other pins in the
80-way connector, and shorts-to-ground between
pin 36 and chassis ground.
Were any wire-to-wire shorts or shorts-to-ground
wiring defects found?
NOTE: The vehicle OEM has responsibility for all
external wiring harness repairs. Harness repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Go to Step 11
Coordinate with the vehicle OEM to repair or
replace the vehicle wiring.
Is the repair complete?
Copyright © 2005 General Motors Corp.
6–345
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2729 Pressure Control Solenoid 1 (PCS1) Control Circuit Low (cont’d)
Step
6
Action
1. Turn OFF the ignition.
2. Install J 47279 Transmission Breakout to the
transmission 20-way connector. Leave the OEM
harness disconnected.
3. Using a DVOM, test for wire-to-wire shorts
between pin 4 and all other pins in the 20-way
connector, and shorts-to-ground between pin 4
and chassis ground.
Value(s)
Yes
Go to Step 7
No
Go to Step 10
.
Go to Step 8
Go to Step 9
NOTE: The resistance value between pins 8 and 6
will read normal solenoid resistance. The resistance
value between pins 4 and 5, and between 4 and 9
will be twice normal solenoid resistance.
7
8
9
10
11
6–346
Were any wire-to-wire shorts, or shorts-to-ground
found?
1. Remove the hydraulic control module assembly.
2. Inspect the internal harness for wire-to-wire
shorts, or shorts-to-ground.
Were any wire-to-wire shorts, or shorts-to-ground
found?
Repair or replace the internal wiring harness.
Is the repair complete?
Replace PCS1.
Is the replacement complete?
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
Refer to TCM diagnostic procedure, Section 3–6.
Is Section 3–6 complete?
In order to verify your repair:
1. Clear the DTC.
2. Drive the vehicle under conditions noted in
failure records.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Go to Step 11
Go to Step 11
Go to Step 12
Begin the
diagnosis again.
Go to Step 1
System OK
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2730 Pressure Control Solenoid 1 (PCS1) Control Circuit High
END VIEW OF
80-WAY CONNECTOR
END VIEW OF
20-WAY CONNECTOR
1
6
7
10
11
14
15
20
61
80
41
60
21
40
1
20
TRANSMISSION
HSD2
PCS1
PCS2
PCS3
SS1
TCM
6
4
5
9
10
WIRE 171
WIRE 136
WIRE 152
WIRE 133
WIRE 151
71
HSD2
V BATTERY
36
52
33
51
V09067.00.00
Circuit Description
Pressure Control Solenoid 1 (PCS1) is a normally open (N/O) solenoid used to apply the C1 clutch in first through
fourth range. The TCM commands the solenoid OFF to produce hydraulic pressure in the clutch apply circuit.
When PCS1 is commanded ON, the C1 clutch is released.
The TCM sends control current to PCS1 from High Side Driver 2 (HSD2) via wire 171. HSD2 is continuously ON
unless the TCM detects a fault condition. The TCM regulates the amount of current to PCS1 by switching PCS1
Low Side Driver (LSD) ON and OFF. Wire 136 completes the circuit between PCS1 and its LSD. DTC P2730
indicates that the TCM has detected a short-to-battery condition in the low side of PCS1 electrical circuit.
Conditions for Running the DTC
• The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater
than 9V and less than 32V (24V TCM).
• TCM initialization is in process or engine speed is greater than 200 rpm and less than 7500 rpm for 5 seconds.
Conditions for Setting the DTC
DTC P2730 is set when the TCM detects a short-to-battery in the PCS1 return circuit for more than 2 seconds.
Actions Taken When the DTC Sets
When DTC P2730 is active, the following conditions will occur:
• The CHECK TRANS light illuminates.
• DTC is stored in TCM history.
• Hydraulic default (SOL OFF) is commanded. The shift selector position and hydraulic state of latch valves
determines the range attained.
Copyright © 2005 General Motors Corp.
6–347
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2730 Pressure Control Solenoid 1 (PCS1) Control Circuit High
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
• DTC P2730 indicates a short-to-battery in the electrical circuit for PCS1.
•
You may have to drive the vehicle in order to experience a fault. Use the data obtained from failure records to
determine transmission range and/or certain vehicle operating variables such as temperature, run time etc. This
data can be useful in reproducing the failure mode when DTC was set.
•
Inspect the wiring for poor electrical connections at the TCM and transmission connector. Look for the
following conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
•
Inspect OEM wiring harness routing, look for possible contact points where chafing could occur leading to an
open or short circuit condition. Moving parts on the vehicle could be contacting the harness; this includes
parking brake drum, suspension components, etc.
•
When diagnosing for an intermittent short or open, massage the wiring harness while watching the test
equipment for a change.
•
Advanced Troubleshooting (requires a frequency-capable digital multimeter, if available)—measure solenoid
LSD functionality as follows:
1. Install TCM breakout harness adapter J 47275 between the 80-way connectors of the TCM and OEM
harness.
2. Set up a frequency-capable digital multimeter, e.g. Fluke 87, to monitor frequency by selecting the
VOLTS-DC scale and depressing the HERTZ button once.
3. Connect the RED test lead to the solenoid low side pin at TCM breakout harness adapter J 47275. Connect the BLACK test lead to the isolated ground pin.
4. Use Allison DOC™ For PC–Service Tool solenoid test function to command the solenoid ON and OFF.
5. Frequency should read in the KILOHERTZ range when the driver is commanded ON. Frequency should
read 0 hertz when the driver is commanded OFF.
Test Description
This DTC requires the use of the J 47275 TCM Breakout and J 47279 Transmission Breakout. The numbers below
refer to step numbers on the diagnostic table.
2. This step tests for the proper ignition voltage.
3. This step tests for an active DTC.
4. This step tests for wire-to-wire shorts between wire 136 and other wires in the OEM chassis harness.
6. This step tests for the wire-to-wire shorts in the transmission internal harness.
6–348
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2730 Pressure Control Solenoid 1 (PCS1) Control Circuit High
Step
1
2
3
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
1. Install the Allison DOC™ For PC–Service Tool. 9–18V (12V TCM)
18–32V (24V TCM)
2. Start the engine.
3. Record the failure records.
4. Monitor ignition voltage.
Is the voltage within the specified values?
1. Clear the DTC.
2. Start the engine and test drive the vehicle.
3. Attempt to duplicate the same conditions
observed in the failure records (range attained,
temperature, etc.).
Yes
Go to Step 2
Go to Step 3
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Resolve voltage
problem.
Go to Step 4
Go to
Diagnostic Aids
Go to Step 5
Go to Step 6
NOTE: This DTC is intended to detect short-tobattery condition in the PCS1 electrical circuit.
4
5
Did DTC P2730 return?
NOTE: Review Section 4—Wire Test Procedures
before performing steps.
1. Turn OFF the ignition.
2. Disconnect the TCM 80-way connector.
3. Install the OEM-side of the 80-way connector to
the J 47275 TCM Breakout. Leave the TCM
disconnected.
4. Disconnect the transmission 20-way connector.
5. Inspect the routing of wire 171 in the chassis
harness between the TCM and the transmission
connector.
6. At J 47275-1 TCM Overlay, test for wire-to-wire
shorts between pin 36 and all other pins in the
80-way connector.
Were any wire-to-wire shorts found?
NOTE: The vehicle OEM has responsibility for all
external wiring harness repairs. Harness repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Go to Step 11
Coordinate with the vehicle OEM to repair or
replace the vehicle wiring.
Is the repair complete?
Copyright © 2005 General Motors Corp.
6–349
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2730 Pressure Control Solenoid 1 (PCS1) Control Circuit High (cont’d)
Step
6
Action
1. Turn OFF the ignition.
2. Install J 47279 Transmission Breakout to the
transmission 20-way connector. Leave the OEM
harness disconnected.
3. Using a DVOM, test for wire-to-wire shorts
between pin 4 and all other pins in the 20-way
connector, and shorts-to-ground between pin 4
and chassis ground.
Value(s)
Yes
Go to Step 7
No
Go to Step 10
Refer to Solenoid
Resistance Chart
(Appendix K)
Go to Step 8
Go to Step 9
NOTE: The resistance value between pins 4 and 6
will read normal solenoid resistance. The resistance
value between pins 4 and 5, between 4 and 9, and
between 4 and 10 will be twice normal solenoid
resistance.
7
8
9
10
11
6–350
Were any wire-to-wire shorts, or shorts-to-ground
found?
1. Remove the hydraulic control module assembly.
2. Inspect the internal harness for wire-to-wire
shorts.
Were any wire-to-wire shorts, or shorts-to-ground
found?
Repair or replace the internal wiring harness.
Is the repair complete?
Replace PCS1.
Is the replacement complete?
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
Refer to TCM diagnostic procedure, Section 3–6.
Is Section 3–6 complete?
In order to verify your repair:
1. Clear the DTC.
2. Drive the vehicle under conditions noted in
failure records.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Go to Step 11
Go to Step 11
Go to Step 11
Begin the
diagnosis again.
Go to Step 1
System OK
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2736 Pressure Control Solenoid 5 (PCS5) Control Circuit Open
END VIEW OF
20-WAY CONNECTOR
END VIEW OF
80-WAY CONNECTOR
1
6
7
10
11
14
15
20
61
80
41
60
21
40
1
20
TRANSMISSION
HSD3
TCC
SS2
TCM
11
12
17
WIRE 131
WIRE 137
WIRE 119
(7-SPEED MODELS)
31
HSD3
V BATTERY
37
19
15
RTDR ACCUM
HSD3
SS2
B
A
WIRE 131
WIRE 119
RTDR OR
DIFF LOCK (T-CASE)
HSD3
PCS5
B
A
WIRE 131
WIRE 115
V09068.00.00
Circuit Description
Pressure Control Solenoid 5 (PCS5) is a normally closed (N/C) solenoid used to apply the retarder solenoid
(retarder units) or differential lock solenoid (3000 7-speed only). The TCM commands the solenoid ON to produce
hydraulic pressure in the control circuit. When PCS5 is commanded OFF, the control circuit is deactivated.
The TCM sends control current to PCS5 from High Side Driver 3 (HSD3) via wire 131. HSD3 is continuously ON
unless the TCM detects a fault condition. The TCM regulates the amount of current to PCS5 by switching PCS5
Low Side Driver (LSD) ON and OFF. Wire 115 completes the circuit between PCS5 and its LSD. DTC P2736
indicates that the TCM has detected an open condition in PCS5 electrical circuit. The open condition may exist in
the high side (wire 131) or low side (wire 115).
Copyright © 2005 General Motors Corp.
6–351
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2736 Pressure Control Solenoid 5 (PCS5) Control Circuit Open
Conditions for Running the DTC
•
The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater
than 9V and less than 32V (24V TCM).
•
TCM initialization is in process or engine speed is greater than 200 rpm and less than 7500 rpm for 5 seconds.
Conditions for Setting the DTC
DTC P2736 is set when the TCM detects an open circuit on the PCS5 return circuit for more than 2 seconds.
Actions Taken When the DTC Sets
When DTC P2736 is active, the following conditions will occur:
•
The CHECK TRANS light illuminates.
•
DTC is stored in TCM history.
•
The TCM inhibits retarder operation.
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
•
DTC P2736 indicates an open in the electrical circuit for PCS5. In addition to PCS5, HSD3 also supplies
power to solenoids torque converter clutch (TCC) and SS2. If DTC P2736 is accompanied by DTC P0975 and
P2761, the open is most likely in the high side of the circuit.
•
You may have to drive the vehicle in order to experience a fault. Use the data obtained from failure records to
determine transmission range and/or certain vehicle operating variables such as temperature, run time etc. This
data can be useful in reproducing the failure mode when DTC was set.
•
Inspect the wiring for poor electrical connections at the TCM and transmission connector. Look for the
following conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
•
Inspect OEM wiring harness routing, look for possible contact points where chafing could occur leading to an
open or short circuit condition. Moving parts on the vehicle could be contacting the harness; this includes
parking brake drum, suspension components, etc.
•
When diagnosing for an intermittent short or open, massage the wiring harness while watching the test
equipment for a change.
6–352
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
Test Description
This DTC requires the use of the J 47275 TCM Breakout and J 47279 Transmission Breakout. The numbers below
refer to step numbers on the diagnostic table.
2. This step tests for the proper ignition voltage.
3. This step tests for an active DTC.
4. This step tests the OEM harness for an excessive voltage caused by an open condition in either wire 131
or wire 115 of the OEM chassis harness.
6. This step tests for the proper PCS5 resistance.
DTC P2736 Pressure Control Solenoid 5 (PCS5) Control Circuit Open
Step
1
2
3
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
1. Install the Allison DOC™ For PC–Service Tool. 9–18V (12V TCM)
18–32V (24V TCM)
2. Start the engine.
3. Record the failure records.
4. Monitor ignition voltage.
Is the voltage within the specified values?
1. Clear the DTC.
2. Start the engine and test drive the vehicle.
3. Attempt to duplicate the same conditions
observed in the failure records (range attained,
temperature, etc.).
Yes
Go to Step 2
Go to Step 3
Go to Step 4
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Resolve voltage
problem
Go to
Diagnostic Aids
NOTE: This DTC is intended to detect an open
condition in PCS5 electrical circuit.
Did DTC P2736 return?
Copyright © 2005 General Motors Corp.
6–353
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2736 Pressure Control Solenoid 5 (PCS5) Control Circuit Open (cont’d)
Step
4
Action
NOTE: Review Section 4—Wire Test Procedures
before performing steps.
1. Turn OFF the ignition.
2. Install J 47275 TCM Breakout between the OEM
and TCM 80-way connectors.
3. Install J 47279 Transmission Breakout between
the OEM and transmission 20-way connectors.
4. Turn ON the ignition. Leave engine OFF.
5. Using Allison DOC™ For PC–Service Tool, enter
Solenoid Test mode and command PCS5 ON.
6. Determine the voltage drop in the high side of the
PCS5 circuit as follows:
• At J 47275-1 TCM Overlay, measure voltage
between pin 31 and an isolated ground.
• To measure PCS5 high-side voltage:
— At J 47279-1 Transmission Overlay,
measure voltage between RTDR FEED
THRU-B and isolated ground (retarder
units), OR
— Back probe pin B of the T-case 6-way
Cannon connector using jumper wire kit
J39197 or equivalent.
— Measure voltage between T-case-B and
isolated ground (3000 7-speed only).
• Subtract the two voltage measurements to
obtain the voltage drop in the circuit.
7. Determine the voltage drop in the low side of the
PCS5 circuit as follows:
• At J 47275-1 TCM Overlay, measure voltage
between pin 15 and an isolated ground.
• To measure PCS5 low-side voltage:
— At J 47279-1 Transmission Overlay,
measure voltage between RTDR FEED
THRU-A and isolated ground (retarder
units), OR
— Back probe pin B of the T-case 6-way
Cannon connector using jumper wire kit
J39197 or equivalent.
— Measure voltage between T-case-B and
isolated ground (3000 7-speed only).
• Subtract the two voltage measurements to
obtain the voltage drop in the circuit.
Value(s)
NOTE: A voltage drop of more than 0.5V across
either circuit indicates an excessive voltage loss in
the OEM harness.
Did either high-side or low-side voltage drop exceed
0.5VDC?
6–354
Copyright © 2005 General Motors Corp.
Yes
Go to Step 5
No
Go to Step 6
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2736 Pressure Control Solenoid 5 (PCS5) Control Circuit Open (cont’d)
Step
5
6
7
8
9
Action
NOTE: The vehicle OEM has responsibility for all
external wiring harness repairs. Harness repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Coordinate with the vehicle OEM to repair or
replace the vehicle wiring.
Is the repair complete?
1. Turn OFF the ignition.
2. Disconnect the OEM PCS5 connector from
J 47279 Transmission Breakout.
3. Using a DVOM, measure the resistance between
pins A and B of the RTDR FEED THRU
connector (retarder units) or T-case connector
(3000 7-speed only).
Is the resistance within the specified value?
1. Remove the retarder valve body (retarder units)
or T-case (3000 7-speed only).
2. Replace PCS5.
Is the replacement complete?
Value(s)
Yes
Go to Step 9
No
Refer to Solenoid
Resistance Chart
(Appendix K)
Go to Step 8
Go to Step 7
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
Refer to TCM diagnostic procedure, Section 3–6.
Is Section 3–6 complete?
In order to verify your repair:
1. Clear the DTC.
2. Drive the vehicle under conditions noted in
failure records.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Go to Step 9
Go to Step 9
Begin the
diagnosis again.
Go to Step 1
System OK
6–355
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2738 Pressure Control Solenoid 5 (PCS5) Control Circuit Low
END VIEW OF
20-WAY CONNECTOR
END VIEW OF
80-WAY CONNECTOR
1
6
7
10
11
14
15
20
61
80
41
60
21
40
1
20
TRANSMISSION
HSD3
TCC
SS2
TCM
11
12
17
WIRE 131
WIRE 137
WIRE 119
(7-SPEED MODELS)
31
HSD3
V BATTERY
37
19
15
RTDR ACCUM
HSD3
SS2
B
A
WIRE 131
WIRE 119
RTDR OR
DIFF LOCK (T-CASE)
HSD3
PCS5
B
A
WIRE 131
WIRE 115
V09068.00.00
Circuit Description
Pressure Control Solenoid 5 (PCS5) is a normally closed (N/C) solenoid used to apply the retarder solenoid
(retarder units) or differential lock solenoid (3000 7-speed only). The TCM commands the solenoid ON to produce
hydraulic pressure in the control circuit. When PCS5 is commanded OFF, the control circuit is deactivated.
The TCM sends control current to PCS5 from High Side Driver 3 (HSD3) via wire 131. HSD3 is continuously ON
unless the TCM detects a fault condition. The TCM regulates the amount of current to PCS5 by switching PCS5
Low Side Driver (LSD) ON and OFF. Wire 115 completes the circuit between PCS5 and its LSD. DTC P2738
indicates that the TCM has detected a short-to-ground condition in the low side of PCS5 electrical circuit.
6–356
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2738 Pressure Control Solenoid 5 (PCS5) Control Circuit Low
Conditions for Running the DTC
• The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater
than 9V and less than 32V (24V TCM).
•
TCM initialization is in process or engine speed is greater than 200 rpm and less than 7500 rpm for 5 seconds.
Conditions for Setting the DTC
DTC P2738 is set when the TCM detects a short-to-ground in the PCS5 return circuit for more than 2 seconds.
Actions Taken When the DTC Sets
When DTC P2738 is active, the following conditions will occur:
•
The CHECK TRANS light illuminates.
•
DTC is stored in TCM history.
•
The TCM allows operation in second through sixth range, and in Neutral and Reverse.
•
The TCM inhibits retarder and TCC operation.
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
• DTC P2738 indicates a short-to-ground in the electrical circuit for PCS5.
• You may have to drive the vehicle in order to experience a fault. Use the data obtained from failure records to
determine transmission range and/or certain vehicle operating variables such as temperature, run time etc. This
data can be useful in reproducing the failure mode when DTC was set.
• Inspect the wiring for poor electrical connections at the TCM and transmission connector. Look for the
following conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
• Inspect OEM wiring harness routing, look for possible contact points where chafing could occur leading to an
open or short circuit condition. Moving parts on the vehicle could be contacting the harness; this includes
parking brake drum, suspension components, etc.
•
When diagnosing for an intermittent short or open, massage the wiring harness while watching the test
equipment for a change.
•
Advanced Troubleshooting (requires a frequency-capable digital multimeter, if available)—measure solenoid
LSD functionality as follows:
1. Install TCM breakout harness adapter J 47275 between the 80-way connectors of the TCM and OEM
harness.
2. Set up a frequency-capable digital multimeter, e.g. Fluke 87, to monitor frequency by selecting the
VOLTS-DC scale and depressing the HERTZ button once.
Copyright © 2005 General Motors Corp.
6–357
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
3. Connect the RED test lead to the solenoid low side pin at TCM breakout harness adapter J 47275. Connect the BLACK test lead to the isolated ground pin.
4. Use Allison DOC™ For PC–Service Tool.
5.
solenoid test function to command the solenoid ON and OFF.
6. Frequency should read in the KILOHERTZ range when the driver is commanded ON. Frequency should
read 0 hertz when the driver is commanded OFF.
Test Description
The numbers below refer to step numbers on the diagnostic table.
2. This step tests for the proper ignition voltage.
3. This step tests for an active DTC.
4. This step tests for wire-to-wire shorts or a short-to-ground condition in wire 115.
6. This step tests for short-to-ground in the internal solenoid circuit.
DTC P2738 Pressure Control Solenoid 5 (PCS5) Control Circuit Low
Step
1
2
3
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
1. Install the Allison DOC™ For PC–Service Tool. 9–18V (12V TCM)
18–32V (24V TCM)
2. Start the engine.
3. Record the failure records.
4. Monitor ignition voltage.
Is the voltage within the specified values?
1. Clear the DTC.
2. Start the engine and test drive the vehicle.
3. Attempt to duplicate the same conditions
observed in the failure records (range attained,
temperature, etc.).
NOTE: This DTC is intended to detect a short-toground condition in the PCS5 electrical circuit.
Did DTC P2738 return?
6–358
Copyright © 2005 General Motors Corp.
Yes
Go to Step 2
Go to Step 3
Go to Step 4
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Resolve voltage
problem
Go to
Diagnostic Aids
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2738 Pressure Control Solenoid 5 (PCS5) Control Circuit Low (cont’d)
Step
4
5
6
7
8
9
Action
NOTE: Review Section 4—Wire Test Procedures
before performing steps.
1. Turn OFF the ignition.
2. Disconnect the TCM 80-way connector.
3. Install the OEM-side of the 80-way connector to
the J 47275 TCM Breakout. Leave the TCM
disconnected.
4. Disconnect the retarder feedthrough or T-case
connector.
5. Inspect the routing of wire 115 in the chassis
harness between the TCM and the PCS5
connector.
6. At J 47275-1 TCM Overlay, test for wire-to-wire
shorts between pin 15 and all other pins in the
80-way connector, and shorts-to-ground between
pin 15 and chassis ground.
Were any wire-to-wire shorts or shorts-to-ground
wiring defects found?
NOTE: The vehicle OEM has responsibility for all
external wiring harness repairs. Harness repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Value(s)
Coordinate with the vehicle OEM to repair or
replace the vehicle wiring.
Is the repair complete?
1. Turn OFF the ignition.
2. Using a DVOM, test for shorts-to-ground
between pin A of retarder feed through or T-case
connector and chassis ground.
Were any shorts-to-ground found?
1. Remove the retarder valve body (retarder units)
or T-case (3000 7-speed only).
2. Replace PCS5.
Is the replacement complete?
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
Refer to TCM diagnostic procedure, Section 3–6.
Is Section 3–6 complete?
In order to verify your repair:
1. Clear the DTC.
2. Drive the vehicle under conditions noted in
failure records.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 5
No
Go to Step 6
Go to Step 9
Go to Step 7
Go to Step 8
Go to Step 9
Go to Step 9
Begin the
diagnosis again.
Go to Step 1
System OK
6–359
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2739 Pressure Control Solenoid 5 (PCS5) Control Circuit High
END VIEW OF
20-WAY CONNECTOR
END VIEW OF
80-WAY CONNECTOR
1
6
7
10
11
14
15
20
61
80
41
60
21
40
1
20
TRANSMISSION
HSD3
TCC
SS2
TCM
11
12
17
WIRE 131
WIRE 137
WIRE 119
(7-SPEED MODELS)
31
HSD3
V BATTERY
37
19
15
RTDR ACCUM
HSD3
SS2
B
A
WIRE 131
WIRE 119
RTDR OR
DIFF LOCK (T-CASE)
HSD3
PCS5
B
A
WIRE 131
WIRE 115
V09068.00.00
Circuit Description
Pressure Control Solenoid 5 (PCS5) is a normally closed (N/C) solenoid used to apply the retarder solenoid
(retarder units) or differential lock solenoid (3000 7-speed only). The TCM commands the solenoid ON to produce
hydraulic pressure in the control circuit. When PCS5 is commanded OFF, the control circuit is deactivated.
The TCM sends control current to PCS5 from High Side Driver 3 (HSD3) via wire 131. HSD3 is continuously ON
unless the TCM detects a fault condition. The TCM regulates the amount of current to PCS5 by switching PCS5
Low Side Driver (LSD) ON and OFF. Wire 115 completes the circuit between PCS5 and its LSD. DTC P2739
indicates that the TCM has detected a short-to-battery condition in the low side of PCS5 electrical circuit.
Conditions for Running the DTC
• The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater
than 9V and less than 32V (24V TCM).
• TCM initialization is in process or engine speed is greater than 200 rpm and less than 7500 rpm for 5 seconds.
6–360
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2739 Pressure Control Solenoid 5 (PCS5) Control Circuit High
Conditions for Setting the DTC
DTC P2739 is set when the TCM detects a short-to-battery in the PCS5 return circuit for more than 2 seconds.
Actions Taken When the DTC Sets
When DTC P2739 is active, the following conditions will occur:
•
The CHECK TRANS light illuminates.
•
DTC is stored in TCM history.
•
The TCM inhibits retarder operation.
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ diagnostic tool can be used to clear the DTC from the TCM history. The TCM automatically
clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
• DTC P2739 indicates a short-to-battery in the electrical circuit for PCS5.
•
You may have to drive the vehicle in order to experience a fault. Use the data obtained from failure records to
determine transmission range and/or certain vehicle operating variables such as temperature, run time etc. This
data can be useful in reproducing the failure mode when DTC was set.
•
Inspect the wiring for poor electrical connections at the TCM and transmission connector. Look for the
following conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
Inspect OEM wiring harness routing, look for possible contact points where chafing could occur leading to an
open or short circuit condition. Moving parts on the vehicle could be contacting the harness; this includes
parking brake drum, suspension components, etc.
•
•
When diagnosing for an intermittent short or open, massage the wiring harness while watching the test
equipment for a change.
•
Advanced Troubleshooting (requires a frequency-capable digital multimeter, if available)—measure solenoid
LSD functionality as follows:
1. Install TCM breakout harness adapter J 47275 between the 80-way connectors of the TCM and OEM
harness.
2. Set up a frequency-capable digital multimeter, e.g. Fluke 87, to monitor frequency by selecting the
VOLTS-DC scale and depressing the HERTZ button once.
3. Connect the RED test lead to the solenoid low side pin at TCM breakout harness adapter J 47275. Connect the BLACK test lead to the isolated ground pin.
4. Use Allison DOC™ For PC–Service Tool solenoid test function to command the solenoid ON and OFF.
5. Frequency should read in the KILOHERTZ range when the driver is commanded ON. Frequency should
read 0 hertz when the driver is commanded OFF.
Copyright © 2005 General Motors Corp.
6–361
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
Test Description
This DTC requires the use of the J 47275 TCM Breakout. The numbers below refer to step numbers on the
diagnostic table.
2. This step tests for the proper ignition voltage.
3. This step tests for an active DTC.
4. This step tests for wire-to-wire shorts between wire 115 and other wires in the OEM chassis harness.
6. This step tests for proper PCS5 resistance.
DTC P2739 Pressure Control Solenoid 5 (PCS5) Control Circuit High
Step
1
2
3
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
1. Install the Allison DOC™ For PC–Service Tool. 9–18V (12V TCM)
18–32V (24V TCM)
2. Start the engine.
3. Record the failure records.
4. Monitor ignition voltage.
Is the voltage within the specified values?
1. Clear the DTC.
2. Start the engine and test drive the vehicle.
3. Attempt to duplicate the same conditions
observed in the failure records (range attained,
temperature, etc.).
Yes
Go to Step 2
Go to Step 3
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Resolve voltage
problem
Go to Step 4
Go to
Diagnostic Aids
Go to Step 5
Go to Step 6
NOTE: This DTC is intended to detect a short-tobattery condition in the PCS5 electrical circuit.
4
6–362
Did DTC P2739 return?
NOTE: Review Section 4—Wire Test Procedures
before performing steps.
1. Turn OFF the ignition.
2. Disconnect the TCM 80-way connector.
3. Install the OEM-side of the 80-way connector to
the J 47275 TCM Breakout. Leave the TCM
disconnected.
4. Disconnect the retarder feedthrough or T-case
connector.
5. Inspect the routing of wires 115 and 131 in the
chassis harness between the TCM and the PCS5
connector.
6. At J 47275-1 TCM Overlay, test for wire-to-wire
shorts between pin 15 and all other pins in the
80-way connector.
Were any wire-to-wire shorts found?
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2739 Pressure Control Solenoid 5 (PCS5) Control Circuit High (cont’d)
Step
5
6
7
8
9
Action
NOTE: The vehicle OEM has responsibility for all
external wiring harness repairs. Harness repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Coordinate with the vehicle OEM to repair or
replace the vehicle wiring.
Is the repair complete?
1. Turn OFF the ignition.
2. Using a DVOM, measure resistance across pins A
and B of PCS5.
Is resistance within the correct values?
1. Remove the retarder valve body (retarder units)
or T-case (3000 7-speed only).
2. Replace PCS5.
Is replacement complete?
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
Value(s)
Yes
Go to Step 9
No
Refer to Solenoid
Resistance Chart
(Appendix K)
Go to Step 8
Go to Step 7
Refer to TCM diagnostic procedure, Section 3–6.
Is Section 3–6 complete?
In order to verify your repair:
1. Clear the DTC.
2. Drive the vehicle under conditions noted in
failure records.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Go to Step 9
Go to Step 9
Begin the
diagnosis again.
Go to Step 1
System OK
6–363
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2740 Retarder Oil Temperature Hot
Refer to Retarder Hydraulic Schematic
Circuit Description
During retarder operation, the retarder housing is filled and pressurized with transmission fluid. This fluid acts on
the vaned rotor assembly and impedes rotation of the transmission output shaft, converting a significant amount of
rotational energy into heat in the process. Additionally, when the retarder is activated the retarder control valve
supplies main pressure to the large autoflow valve in the retarder housing. The autoflow valve is repositioned
during retarder operation to direct hot fluid in the retarder cavity to the transmission oil cooler. The retarder
temperature sensor monitors fluid temperature in the retarder-housing cavity.
Conditions for Running the DTC
The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater than
9V and less than 32V (24V TCM).
Conditions for Setting the DTC
The TCM detects retarder oil temperature greater than 165°C (330°C) for more than 10 seconds.
Actions Taken When the DTC Sets
When DTC P2740 is active, the following conditions will occur:
•
The TCM does not illuminate the CHECK TRANS light.
•
DTC is stored in TCM history.
Conditions for Clearing the DTC/CHECK TRANS Light
•
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without
failure.
•
The TCM cancels the DTC default actions when the fault no longer exists and the DTC passes test.
Diagnostic Aids
•
The Allison DOC™ For PC–Service Tool retarder oil temperature should rise steadily during retarder
operation and drop to near sump temp when the retarder is deactivated.
•
A stuck autoflow valve can cause overheating in retarder-equipped transmissions. Refer to Section 8 for
general troubleshooting of performance complaints.
•
Other possible causes include:
— Prolonged retarder use
— Low fluid level
— High fluid level
— A retarder apply system that allows the throttle and retarder to be applied simultaneously
— A cooler that is inadequately sized for the retarder.
6–364
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
Test Description
This DTC requires the use of the J 47275 TCM Breakout. The numbers below refer to step numbers on the
diagnostic table.
2. This step tests for proper transmission fluid level and condition.
3. This step monitors the status of DTC P2740.
4. This step verifies which condition has set the DTC P2740.
5. This step tests for proper resistance value in entire circuit.
6. This step tests the resistance value of the retarder temperature sensor.
10. This step tests the condition of the vehicle cooling system.
11. This step tests for proper cooler pressure drop.
12. This step tests for deficiencies with the transmission oil cooler and cooling lines.
DTC P2740 Retarder Oil Temperature Hot
Step
1
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
2
Perform the Fluid Checking Procedure (refer to
appropriate mechanic’s tips).
Is the transmission fluid level correct?
1. Install the Allison DOC™ For PC–Service Tool.
2. Install a temperature gauge at the retarder outlet
port.
3. Turn ON the ignition.
4. Record the failure records.
5. Clear the DTCs.
6. Drive the vehicle and monitor retarder
temperature on Allison DOC™ For PC–Service
Tool.
Did DTC P2740 return?
Compare the manual temperature reading to the
Allison DOC™ For PC–Service Tool retarder
temperature when the DTC is set.
Does the manual temperature reading confirm the
retarder oil temperature is actually hot when DTC
P2740 is logged?
3
4
Value(s)
Copyright © 2005 General Motors Corp.
Yes
Go to Step 2
Go to Step 3
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Go to Fluid Check
Procedure (refer to
mechanic’s tips)
Go to Step 4
Go to
Diagnostic Aids
Go to Step 10
Go to Step 5
6–365
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2740 Retarder Oil Temperature Hot (cont’d)
Step
5
6
7
8
9
Action
1. Turn OFF the ignition.
2. Disconnect the 80-way connector from the TCM.
3. Connect J 47425 TCM Breakout to the OEM
connector. Leave the TCM disconnected from
J 47275 TCM Breakout.
4. Using a DVOM at J 47275-1 TCM Overlay,
measure the resistance between pin 75 and 58.
5. Refer to Appendix Q and find the retarder oil
temperature that corresponds to the resistance
value determined in the preceding step.
Does the value listed in Appendix Q match the
manual retarder temperature reading?
1. Disconnect the retarder temperature sensor
connector.
2. Using a DVOM, measure resistance at retarder
temp sensor pins A and B.
3. Refer to Appendix Q and find the retarder oil
temperature that corresponds to the resistance
value determined in the preceding step.
Does the value listed in Appendix Q match the
manual retarder temperature reading?
NOTE: The vehicle OEM has responsibility for all
external wiring harness repairs. Harness repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Value(s)
Refer to
Appendix Q
Yes
Go to Step 9
No
Go to Step 6
Refer to
Appendix Q
Go to Step 7
Go to Step 8
Coordinate with the vehicle OEM to repair or
replace the vehicle wiring.
Is the repair complete?
Replace the retarder temperature sensor.
Is the replacement complete?
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
Refer to TCM diagnostic procedure, Section 3–6.
Is Section 3–6 complete?
6–366
Copyright © 2005 General Motors Corp.
Go to Step 14
Go to Step 14
Go to Step 14
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2740 Retarder Oil Temperature Hot (cont’d)
Step
10
11
12
13
14
Action
1. Inspect the engine cooling system for the
following conditions:
• Air flow restrictions
• Air flow blockage
• System fluid level and condition
• Debris
2. Inspect the transmission cooling system for the
following conditions:
• Air flow restrictions
• Air flow blockage
• System fluid level and condition
• Damaged cooler lines and hoses
Value(s)
Did you find and correct the condition?
1. Install pressure gauges in the “to” and “from”
Refer to
cooler lines.
Table 6–18 or 6–19
2. Start the engine.
3. Subtract the “from cooler” pressure from the “to
cooler” pressure to obtain pressure drop across
the transmission oil cooler.
4. Verify cooler pressure drop satisfies limits of
Table 6–16 (4000 Product Family) or Table 6–17
(3000 Product Family).
Is cooler pressure drop within specified values?
Inspect the transmission cooling system for the
following conditions:
• Transmission cooler lines reversed.
• Cooler lines restricted.
• Improperly sized cooler fittings.
• Inadequately sized cooler.
Did you find any problems with the vehicle’s
cooling system?
NOTE: The vehicle OEM has responsibility for all
vehicle cooling system repairs. Cooling system
repairs performed by Allison Transmission
distributors and dealers are not covered by Allison
Transmission warranty.
Coordinate with the vehicle OEM to repair the
vehicle cooling system.
Is the repair complete?
In order to verify your repair:
1. Clear the DTC.
2. Using Allison DOC™ For PC–Service Tool,
monitor retarder temperature.
3. Drive the vehicle under normal operating
conditions. Watch for significant change in
temperature.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 14
No
Go to Step 11
Go to
Diagnostic Aids
Go to Step 12
Go to Step 13
Go to
Diagnostic Aids
Go to Step 13
Go to
Diagnostic Aids
Begin the
diagnosis again.
Go to Step 1
System OK
6–367
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2740 Retarder Oil Temperature Hot
External Hydraulic Circuit Characteristics
Basic, PTO, 93°C (200°F) Sump Temperature
Table 6–16. 4000 Product Family
CONVERTER OPERATION
MAXIMUM COOLER FLOW AT MINIMUM PRESSURE DROP
Flow
Pressure Drop
Input rpm
L/s
GPM
kPa
psi
600
0.22
3.4
0
0
900
0.38
6.1
0
0
1200
0.55
8.7
0
0
1500
0.80
12.7
0
0
1800
1.03
16.4
0
0
2100
1.13
18.0
0
0
2300
1.20
19.0
0
0
CONVERTER OPERATION
COOLER FLOW AT MAXIMUM ALLOWABLE PRESSURE DROP
600
0.20
3.2
31.0
4.5
900
0.37
5.8
63.0
9.1
1200
0.55
8.7
108.0
15.7
1500
0.77
12.2
167.0
24.2
1800
0.92
14.5
231.0
30.9
2100
0.97
15.3
238.0
34.5
2300
1.00
15.9
250.0
36.3
Table 6–17. 3000 Product Family
CONVERTER OPERATION
MAXIMUM COOLER FLOW AT MINIMUM PRESSURE DROP
Flow
6–368
Pressure Drop
Input rpm
L/s
GPM
kPa
psi
600
0.10
1.6
0
0
800
0.23
3.7
0
0
1200
0.47
7.4
0
0
1400
0.61
9.7
0
0
1600
0.74
11.7
0
0
2000
0.94
14.9
0
0
2400
1.19
18.9
0
0
3200
1.28
20.3
0
0
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
Table 6–17. 3000 Product Family (cont’d)
CONVERTER OPERATION
MAXIMUM ALLOWABLE PRESSURE DROP
Flow
Pressure Drop
Input rpm
L/s
GPM
kPa
psi
600
0.10
1.6
10.0
1.5
800
0.23
3.5
40.0
5.8
1200
0.45
7.1
159.0
23.1
1400
0.57
9.0
252.0
36.6
1600
0.67
10.6
338.0
49.0
2000
0.80
12.7
481.0
69.8
2400
0.85
13.5
549.0
79.6
3200
0.85
13.5
549.0
79.6
LOCKUP OPERATION
MAXIMUM COOLER FLOW AT MINIMUM PRESSURE DROP
600
0.10
1.6
0
0
800
0.23
3.7
0
0
1200
0.50
7.9
0
0
1400
0.63
10.0
0
0
1600
0.77
12.2
0
0
2000
0.95
15.1
0
0
2400
1.12
17.8
0
0
2800
1.22
19.3
0
0
3200
1.28
20.3
0
0
LOCKUP OPERATION
MAXIMUM ALLOWABLE PRESSURE DROP
600
0.10
1.6
5.0
0.7
800
0.23
3.7
46.0
6.7
1200
0.48
7.6
148.0
21.5
1400
0.62
9.8
247.0
35.8
1600
0.73
11.6
346.0
50.2
2000
0.90
14.3
561.0
81.4
2400
1.07
17.0
737.0
106.9
2800
1.10
17.4
770.0
111.7
3200
1.10
17.4
791.0
114.7
Copyright © 2005 General Motors Corp.
6–369
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2742 Retarder Oil Temperature Sensor Circuit  Low Input
END VIEW OF
20-WAY CONNECTOR
END VIEW OF
80-WAY CONNECTOR
1
6
7
10
11
14
15
20
61
80
41
60
21
40
1
20
TO RETARDER
CONTROL DEVICES
RETARDER
REQUEST SENSOR
(RESISTANCE
MODULE)
A
PWM
THROTTLE
SOURCE
B
C
TCM
THROTTLE
POSITION
SENSOR (TPS)
OR
ELECTRONIC
BRAKING (EBS)
RTDR PRESSURE
SENSOR
WIRE 156
WIRE 112
C
WIRE 144
B
WIRE 158
A
RETARDER TEMP
ENGINE TEMP
TRANSMISSION
ANALOG RETURN
OIL LEVEL
HALL
A
C
EFFECT
B
SUMP TEMP
19
16
15
18
PS1
NC*
* NORMALLY
3
WIRE 175
WIRE 135
56
RETARDER REQUEST SIGNAL
12
5V SENSOR VOLTAGE
44
THROTTLE POSITION OR
RTDR PRESSURE SIGNAL
58
ANALOG RETURN
75
RETARDER TEMP
35
ENGINE WATER TEMP
16
OIL LEVEL SENSOR
54
SUMP TEMP
77
PS1 DIAGNOSTIC
PRESSURE SWITCH
WIRE 158
WIRE 112
WIRE 116
WIRE 154
WIRE 177
CLOSED
V09069.01.00
6–370
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2742 Retarder Oil Temperature Sensor Circuit  Low Input
Circuit Description
A retarder oil temperature sensor monitors retarder cavity fluid temperature. The sensor consists of a thermistor
that varies its resistance value based on the temperature of the fluid in the retarder housing. The Transmission
Control Module (TCM) supplies a 5V reference voltage signal into a voltage-sensing network that is connected to
one side of the retarder temperature sensor via wire 175. The other side of the temp sensor is connected to the TCM
analog ground wire 158.
The resistance value of the retarder temperature sensor determines the voltage drop in the retarder temperature
sensor circuit. As resistance changes, the voltage drop across the thermistor will also change varying the sensor
input voltage on wire 175. When retarder fluid is cold the sensor resistance is high, which produces a large voltage
drop across the temp sensor circuit. The TCM, therefore, detects a high sensor input voltage during cold conditions.
As the retarder fluid temperature warms to normal operating temperature, the resistance decreases producing a
smaller voltage drop across the temp sensor. As a result, the TCM detects a lower sensor input voltage on wire 175
during hot oil conditions. The TCM uses retarder temperature information to restrict retarder operation and reduce
fluid temperature when a retarder over-heat condition is detected.
Conditions for Running the DTC
The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater than
9V and less than 32V (24V TCM).
Conditions for Setting the DTC
The TCM detects retarder oil temperature greater than a calibrated value for more than 2.5 seconds.
NOTE:
The TCM is detecting voltage. An unusually low input voltage implies low thermistor resistance, which
corresponds to an illogically high retarder oil temperature measurement.
Actions Taken When the DTC Sets
When DTC P2742 is active, the following conditions will occur:
• The TCM does not illuminate the CHECK TRANS light.
• DTC is stored in TCM history.
• TCM uses default retarder temperature values.
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
• DTC P2742 may be caused by a short-to-ground on wire 175.
•
Review Appendix A for diagnosing intermittent electrical conditions.
•
Inspect the wiring for poor electrical connections at the TCM and retarder temperature sensor. Look for the
following conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
Copyright © 2005 General Motors Corp.
6–371
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
•
When diagnosing for an intermittent short or open, massage the wiring harness while watching the test
equipment for a change.
•
You may have to drive the vehicle and operate the retarder in order to experience a fault.
Test Description
This DTC requires the use of the J 47275 TCM Breakout. The numbers below refer to step numbers on the
diagnostic table.
2.
3.
4.
5.
6.
7.
This step tests for proper transmission fluid level and condition.
This step verifies which condition has set the DTC P2742.
This step tests for the proper 5V reference voltage at TCM.
This step tests for wire-to-wire shorts or shorts-to-ground on wire 175 (Retarder Oil Temp).
This step tests for proper system circuit resistance value.
This step tests the resistance value of the retarder temp sensor.
DTC P2742 Retarder Oil Temperature Sensor Circuit—Low Input
Step
1
2
3
4
6–372
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Perform the Fluid Checking Procedure (refer to
appropriate mechanic’s tips).
Is the transmission fluid level correct?
1. Install the Allison DOC™ For PC–Service Tool.
2. With the engine OFF, turn the ignition to the ON
position.
3. Record the failure records.
4. Clear the DTCs.
5. Monitor the retarder temperature on Allison
DOC™ For PC–Service Tool.
6. Drive the vehicle and observe Allison DOC™ For
PC–Service Tool for an unrealistically high
temperature condition.
Is the Allison DOC™ For PC–Service Tool retarder
oil temperature greater than 178°C (352°F)?
1. Turn OFF the ignition.
2. Install J 47275 TCM Breakout at the TCM.
3. Disconnect the retarder temp sensor connector.
4. Turn ON the ignition.
5. At J 47275-1 TCM Overlay, connect a DVOM
and measure voltage between pins 75 and 58.
Is the voltage within the specified value?
Value(s)
Yes
Go to Step 2
Go to Step 3
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Go to Fluid Check
Procedure (refer to
mechanic’s tips)
>178ºC (352ºF)
Go to Step 4
Go to
Diagnostic Aids
4.75 to 5.0V
Go to Step 6
Go to Step 5
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2742 Retarder Oil Temperature Sensor Circuit—Low Input (cont’d)
Step
5
6
7
8
9
10
11
Action
1. Turn OFF the ignition.
2. Disconnect the TCM from the J 47275 TCM
Breakout. Leave the OEM-side connected.
3. Disconnect the retarder temp sensor connector, if
not disconnected in Step 4.
4. Using a DVOM at J 47275-1 TCM Overlay, test
for pin-to-pin shorts, or shorts-to-ground on
wire 175.
Were any wiring defects found?
1. Turn OFF the ignition.
2. Disconnect the TCM from the J 47275 TCM
Breakout. Leave the OEM-side connected.
3. Reconnect the retarder temp sensor connector.
4. At J 47275-1 TCM Overlay connect a DVOM,
measure the resistance between pin 75 and 58.
Is the resistance within the specified value?
1. Disconnect the retarder temp sensor connector.
2. Using a DVOM, measure resistance between pins
A and B of the retarder temp sensor.
Is the resistance within the specified value?
NOTE: The vehicle OEM has responsibility for all
external wiring harness repairs. Harness repairs
performed by distributors and dealers are not
covered by warranty.
Value(s)
Yes
Go to Step 8
No
Go to Step 10
Refer to
Appendix Q
Go to
Diagnostic Aids
Go to Step 7
Refer to
Appendix Q
Go to Step 8
Go to Step 9
Coordinate with the vehicle OEM to repair or
replace the vehicle wiring.
Is the repair complete?
Replace the retarder temperature sensor.
Is the replacement complete?
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
Refer to TCM diagnostic procedure, Section 3–6.
Is Section 3–6 complete?
In order to verify your repair:
1. Clear the DTC.
2. Using Allison DOC™ For PC–Service Tool,
monitor retarder temperature.
3. Drive the vehicle under normal operating
conditions. Watch for significant change in
temperature.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Go to Step 11
Go to Step 11
Go to Step 11
Begin the
diagnosis again.
Go to Step 1
System OK
6–373
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2743 Retarder Oil Temperature Sensor Circuit—High Input
END VIEW OF
20-WAY CONNECTOR
END VIEW OF
80-WAY CONNECTOR
1
6
7
10
11
14
15
20
61
80
41
60
21
40
1
20
TO RETARDER
CONTROL DEVICES
RETARDER
REQUEST SENSOR
(RESISTANCE
MODULE)
A
PWM
THROTTLE
SOURCE
B
C
TCM
THROTTLE
POSITION
SENSOR (TPS)
OR
ELECTRONIC
BRAKING (EBS)
RTDR PRESSURE
SENSOR
WIRE 156
WIRE 112
C
WIRE 144
B
WIRE 158
A
RETARDER TEMP
ENGINE TEMP
TRANSMISSION
ANALOG RETURN
OIL LEVEL
HALL
A
C
EFFECT
B
SUMP TEMP
19
16
15
18
PS1
NC*
* NORMALLY
3
WIRE 175
WIRE 135
56
RETARDER REQUEST SIGNAL
12
5V SENSOR VOLTAGE
44
THROTTLE POSITION OR
RTDR PRESSURE SIGNAL
58
ANALOG RETURN
75
RETARDER TEMP
35
ENGINE WATER TEMP
16
OIL LEVEL SENSOR
54
SUMP TEMP
77
PS1 DIAGNOSTIC
PRESSURE SWITCH
WIRE 158
WIRE 112
WIRE 116
WIRE 154
WIRE 177
CLOSED
V09069.01.00
6–374
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2743 Retarder Oil Temperature Sensor Circuit—High Input
Circuit Description
A retarder oil temperature sensor monitors retarder cavity fluid temperature. The sensor consists of a thermistor
that varies its resistance value based on the temperature of the fluid in the retarder housing. The Transmission
Control Module (TCM) supplies a 5V reference voltage signal into a voltage-sensing network that is connected to
one side of the retarder temperature sensor via wire 175. The other side of the temperature sensor is connected to
the TCM analog ground wire 158.
The resistance value of the retarder temperature sensor determines the voltage drop in the retarder temperature
sensor circuit. As resistance changes, the voltage drop across the thermistor will also change varying the sensor
input voltage on wire 175. When retarder fluid is cold the sensor resistance is high, which produces a large voltage
drop across the temp sensor circuit. The TCM, therefore, detects a high sensor input voltage during cold conditions.
As the retarder fluid temperature warms to normal operating temperature, the resistance decreases producing a
smaller voltage drop across the temp sensor. As a result, the TCM detects a lower sensor input voltage on wire 175
during hot oil conditions.
Conditions for Running the DTC
The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater than
9V and less than 32V (24V TCM).
Conditions for Setting the DTC
The TCM detects retarder oil temperature less than or equal to a calibrated value for more than 2.5 seconds.
NOTE: The TCM is detecting voltage. A high input voltage implies high thermistor resistance, which
corresponds to an extremely cold retarder oil temperature measurement.
Actions Taken When the DTC Sets
When DTC P2743 is active, the following conditions will occur:
• The TCM does not illuminate the CHECK TRANS light.
• DTC is stored in TCM history.
• TCM uses default retarder temperature values.
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
• DTC P2743 may be caused by an open in wire 175 or 158.
• DTC P2743 may be caused by a short-to-battery on wire 175. If DTC P2743 is accompanied by a DTC P0713
and/or P2185, the problem is likely a short-to-battery on wire 154, wire 135, or wire 175.
• Review Appendix A for diagnosing intermittent electrical fault conditions.
• Inspect the wiring for poor electrical connections at the TCM and retarder temp sensor. Look for the following
conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
Copyright © 2005 General Motors Corp.
6–375
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
•
When diagnosing for an intermittent short or open, massage the wiring harness while watching the test
equipment for a change.
•
You may have to drive the vehicle in order to experience a fault.
Test Description
This DTC requires the use of the J 47275 TCM Breakout. The numbers below refer to step numbers on the
diagnostic table.
2. This step tests for proper transmission fluid level and condition.
3. This step verifies which condition has set the DTC P2743.
4. This step tests for the proper 5V reference voltage at TCM.
5. This step tests for wire-to-wire shorts, shorts-to-ground, or an open on wire 175.
6. This step tests for proper system circuit resistance value.
7. This step tests the resistance value of the internal TFT sensor.
DTC P2743 Retarder Oil Temperature Sensor Circuit—High Input
Step
1
2
3
4
6–376
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Perform the Fluid Checking Procedure (refer to
appropriate mechanic’s tips).
Is the transmission fluid level correct?
1. Install the Allison DOC™ For PC–Service Tool.
2. With the engine OFF, turn the ignition to the ON
position.
3. Record the failure records.
4. Clear the DTCs.
5. Monitor the retarder temperature on Allison
DOC™ For PC–Service Tool.
6. Drive the vehicle and observe Allison DOC™ For
PC–Service Tool for an unrealistically low
temperature condition.
Is the Allison DOC™ For PC–Service Tool transmission fluid temperature less than –45°C (–49°F)?
1. Turn OFF the ignition.
2. Install J 47275 TCM Breakout at the TCM.
3. Disconnect the retarder temp sensor connector.
4. Turn ON the ignition.
5. At J 47275-1 TCM Overlay connect a DVOM
and select the volts-DC scale.
6. Measure voltage between pin 75 and an isolated
ground.
Is the voltage within the specified value?
Value(s)
Yes
Go to Step 2
Go to Step 3
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Go to Fluid Check
Procedure (refer to
mechanic’s tips)
<–45° C (–49° F)
Go to Step 4
Go to
Diagnostic Aids
4.75 to 5.0V
Go to Step 6
Go to Step 5
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2743 Retarder Oil Temperature Sensor Circuit—High Input (cont’d)
Step
5
6
7
Action
1. Turn OFF the ignition.
2. Disconnect the TCM from the J 47275 TCM
Breakout. Leave the OEM-side connected.
3. Disconnect the retarder temperature sensor, if not
disconnected in Step 4.
4. Disconnect the transmission 20-way connector
and engine coolant temperature sensor.
5. Using a DVOM at J 47275-1 TCM Overlay, test
for opens in wire 175 and wire 112.
6. Also test for wire-to-wire shorts, or shorts-tobattery on wire 135, wire 154, or wire 175.
Were any wiring defects found?
1. Turn OFF the ignition.
2. Disconnect the TCM from the J 47275 TCM
Breakout. Leave the OEM-side connected.
3. Reconnect the transmission 20-way connector.
4. At J 47275-1 TCM Overlay connect a DVOM,
measure the resistance at pin 75 and 58.
Is the resistance within the specified value?
8
1. Disconnect the retarder temp sensor connector.
2. Using a DVOM, measure resistance between pins
A and B of the retarder temp sensor.
Is the resistance within the specified value?
NOTE: The vehicle OEM has responsibility for all
external wiring harness repairs. Harness repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
9
Coordinate with the vehicle OEM to repair or
replace the vehicle wiring.
Is the repair complete?
Replace the retarder temperature sensor.
Is the replacement complete?
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
10
11
Value(s)
Yes
Go to Step 8
No
Go to Step 10
Refer to
Appendix Q
Go to
Diagnostic Aids
Go to Step 7
Refer to
Appendix Q
Go to Step 8
Go to Step 9
Refer to TCM diagnostic procedure, Section 3–6.
Is Section 3–6 complete?
In order to verify your repair:
1. Clear the DTC.
2. Using Allison DOC™ For PC–Service Tool,
monitor retarder temperature.
3. Drive the vehicle under normal operating
conditions. Watch for significant change in
temperature.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Go to Step 11
Go to Step 11
Go to Step 11
Begin the
diagnosis again.
Go to Step 1
System OK
6–377
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2761 TCC PCS Control Circuit Open
END VIEW OF
20-WAY CONNECTOR
END VIEW OF
80-WAY CONNECTOR
1
6
7
10
11
14
15
20
61
80
41
60
21
40
1
20
TRANSMISSION
HSD3
TCC
SS2
TCM
11
12
17
WIRE 131
WIRE 137
WIRE 119
(7-SPEED MODELS)
31
HSD3
V BATTERY
37
19
15
RTDR ACCUM
HSD3
SS2
B
A
WIRE 131
WIRE 119
RTDR OR
DIFF LOCK (T-CASE)
HSD3
PCS5
B
A
WIRE 131
WIRE 115
V09068.00.00
Circuit Description
Torque Converter Clutch Pressure Control Solenoid (TCC) is a normally closed (N/C) solenoid used to apply the
torque converter clutch when specific engine and turbine speed conditions are met. The TCM commands the
solenoid ON to produce hydraulic pressure in the torque converter clutch apply circuit. When solenoid TCC is
commanded OFF, torque converter clutch pressure is released.
The TCM sends control current to solenoid TCC from High Side Driver 3 (HSD3) via wire 131. HSD3 is
continuously ON unless the TCM detects a fault condition. The TCM regulates the amount of current to TCC by
switching TCC’s Low Side Driver (LSD) ON and OFF. Wire 137 completes the circuit between TCC and its LSD.
DTC P2761 indicates that the TCM has detected an open condition in solenoid TCC’s electrical circuit. The open
condition may exist in the high side (wire 131) or low side (wire 137).
6–378
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2761 TCC PCS Control Circuit Open
Conditions for Running the DTC
•
The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater
than 9V and less than 32V (24V TCM).
•
TCM initialization is in process or engine speed is greater than 200 rpm and less than 7500 rpm for 5 seconds.
Conditions for Setting the DTC
DTC P2761 is set when the TCM detects an open circuit on the TCC solenoid return circuit for more than
2 seconds.
Actions Taken When the DTC Sets
When DTC P2761 is active, the following conditions will occur:
•
The CHECK TRANS light illuminates.
•
DTC is stored in TCM history.
•
The TCM inhibits TCC operation.
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
•
DTC P2761 indicates an open in the electrical circuit for the TCC solenoid. In addition to TCC, HSD3 also
supplies power to PCS5 and SS2. If DTC P2761 is accompanied by DTCs P0975 and P2736, the open is most
likely in the high side of the circuit.
•
You may have to drive the vehicle in order to experience a fault. Use the data obtained from failure records to
determine transmission range and/or certain vehicle operating variables such as temperature, run time etc. This
data can be useful in reproducing the failure mode when DTC was set.
•
Inspect the wiring for poor electrical connections at the TCM and transmission connector. Look for the
following conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
•
Inspect OEM wiring harness routing, look for possible contact points where chafing could occur leading to an
open or short circuit condition. Moving parts on the vehicle could be contacting the harness; this includes
parking brake drum, suspension components, etc.
•
When diagnosing for an intermittent short or open, massage the wiring harness while watching the test
equipment for a change.
Copyright © 2005 General Motors Corp.
6–379
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
Test Description
This DTC requires the use of the J 47275 TCM Breakout and J 47279 Transmission Breakout. The numbers below
refer to step numbers on the diagnostic table.
2. This step tests for the proper ignition voltage.
3. This step tests for an active DTC.
4. This step tests the OEM harness for an excessive voltage drop caused by an open condition in either wire
131 or wire 137 of the OEM chassis harness.
6. This step tests for an open condition in the transmission internal harness.
7. This step tests for the proper TCC solenoid resistance.
DTC P2761 TCC PCS Control Circuit Open
Step
1
2
3
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
1. Install the Allison DOC™ For PC–Service Tool. 9–18V (12V TCM)
18–32V (24V TCM)
2. Start the engine.
3. Record the failure records.
4. Monitor ignition voltage.
Is the voltage within the specified values?
1. Clear the DTC.
2. Start the engine and test drive the vehicle.
3. Attempt to duplicate the same conditions
observed in the failure records (range attained,
temperature, etc.).
NOTE: This DTC is intended to detect an open
condition in the TCC solenoid electrical circuit.
Did DTC P2761 return?
6–380
Copyright © 2005 General Motors Corp.
Yes
Go to Step 2
Go to Step 3
Go to Step 4
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Resolve voltage
problem
Go to
Diagnostic Aids
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2761 TCC PCS Control Circuit Open (cont’d)
Step
4
Action
NOTE: Review Section 4—Wire Test Procedures
before performing steps.
1. Turn OFF the ignition.
2. Install J 47275 TCM Breakout between the OEM
and TCM 80-way connectors.
3. Install J 47279 Transmission Breakout between
the OEM and transmission 20-way connectors.
4. Turn ON the ignition, leave engine OFF.
5. Using Allison DOC™ For PC–Service Tool, enter
Solenoid Test mode and command solenoid TCC
ON.
6. Determine the voltage drop in the high side of the
TCC circuit as follows:
• At J 47275-1 TCM Overlay, measure voltage
between pin 31 and an isolated ground.
• At J 47279-1 Transmission Overlay, measure
voltage between pin 11 and isolated ground.
• Subtract the two voltage measurements to
obtain the voltage drop in the circuit.
7. Determine the voltage drop in the low side of the
TCC circuit as follows:
• At J 47275-1 TCM Overlay, measure voltage
between pin 37 and an isolated ground.
• At J 47279-1 Transmission Overlay, measure
voltage between pin 12 and isolated ground.
• Subtract the two voltage measurements to
obtain the voltage drop in the circuit.
Value(s)
Yes
Go to Step 5
No
Go to Step 6
NOTE: A voltage drop of more than 0.5V across
either circuit indicates an excessive voltage loss in
the OEM harness.
5
Did either high-side or low-side voltage drop exceed
0.5VDC?
NOTE: The vehicle OEM has responsibility for all
external wiring harness repairs. Harness repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Go to Step 11
Coordinate with the vehicle OEM to repair or
replace the vehicle wiring.
Is the repair complete?
Copyright © 2005 General Motors Corp.
6–381
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2761 TCC PCS Control Circuit Open (cont’d)
Step
6
7
8
9
10
11
6–382
Action
1. Turn OFF the ignition.
2. Disconnect the OEM 20-way connector from
J 47279 Transmission Breakout. Leave the
transmission 20-way connector connected to the
breakout.
3. Using a digital multimeter (DVOM), measure the
resistance between pin 11 and pin 12 in the
transmission 20-way connector.
Is the resistance within the specified value?
1. Remove the hydraulic control module assembly.
2. Disconnect solenoid TCC from the internal
wiring harness.
3. Using a DVOM, measure solenoid TCC
resistance at pins A and B.
Is resistance within the specified values?
Replace the internal wiring harness.
Is the replacement complete?
Replace solenoid TCC.
Is the replacement complete?
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
Value(s)
Refer to Solenoid
Resistance Chart
(Appendix K)
Yes
Go to Step 10
No
Go to Step 7
Refer to Solenoid
Resistance Chart
(Appendix K)
Go to Step 8
Go to Step 9
Refer to TCM diagnostic procedure, Section 3–6.
Is Section 3–6 complete?
In order to verify your repair:
1. Clear the DTC.
2. Drive the vehicle under normal operating
conditions. Watch for significant change in
temperature.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Go to Step 11
Go to Step 11
Go to Step 11
Begin the
diagnosis again.
Go to Step 1
System OK
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2763 TCC PCS Control Circuit High
END VIEW OF
20-WAY CONNECTOR
END VIEW OF
80-WAY CONNECTOR
1
6
7
10
11
14
15
20
61
80
41
60
21
40
1
20
TRANSMISSION
HSD3
TCC
SS2
TCM
11
12
17
WIRE 131
WIRE 137
WIRE 119
(7-SPEED MODELS)
31
HSD3
V BATTERY
37
19
15
RTDR ACCUM
HSD3
SS2
B
A
WIRE 131
WIRE 119
RTDR OR
DIFF LOCK (T-CASE)
HSD3
PCS5
B
A
WIRE 131
WIRE 115
V09068.00.00
Circuit Description
Torque Converter Clutch Pressure Control Solenoid (TCC) is a normally closed (N/C) solenoid used to apply the
torque converter clutch when specific engine and turbine speed conditions are met. The TCM commands the
solenoid ON to produce hydraulic pressure in the torque converter clutch apply circuit. When solenoid TCC is
commanded OFF, torque converter clutch pressure is released.
The TCM sends control current to solenoid TCC from High Side Driver 3 (HSD3) via wire 131. HSD3 is
continuously ON unless the TCM detects a fault condition. The TCM regulates the amount of current to TCC by
switching TCC’s Low Side Driver (LSD) ON and OFF. Wire 137 completes the circuit between TCC and its LSD.
DTC P2763 indicates that the TCM has detected a short-to-battery condition in the low side of solenoid TCC’s
electrical circuit.
Copyright © 2005 General Motors Corp.
6–383
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2763 TCC PCS Control Circuit High
Conditions for Running the DTC
• The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater
than 9V and less than 32V (24V TCM).
•
TCM initialization is in process or engine speed is greater than 200 rpm and less than 7500 rpm for 5 seconds.
Conditions for Setting the DTC
DTC P2763 is set when the TCM detects a short-to-battery in the TCC solenoid return circuit for more than
2 seconds.
Actions Taken When the DTC Sets
When DTC P2763 is active, the following conditions will occur:
•
The CHECK TRANS light illuminates.
•
DTC is stored in TCM history.
•
The TCM inhibits TCC operation.
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
• DTC P2763 indicates a short-to-battery in the electrical circuit for the TCC solenoid.
•
You may have to drive the vehicle in order to experience a fault. Use the data obtained from failure records to
determine transmission range and/or certain vehicle operating variables such as temperature, run time etc. This
data can be useful in reproducing the failure mode when DTC was set.
•
Inspect the wiring for poor electrical connections at the TCM and transmission connector. Look for the
following conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
Inspect OEM wiring harness routing, look for possible contact points where chafing could occur leading to an
open or short circuit condition. Moving parts on the vehicle could be contacting the harness; this includes
parking brake drum, suspension components, etc.
•
•
When diagnosing for an intermittent short or open, massage the wiring harness while watching the test
equipment for a change.
•
Advanced Troubleshooting (requires a frequency-capable digital multimeter, if available)—measure solenoid
LSD functionality as follows:
1. Install TCM breakout harness adapter J 47275 between the 80-way connectors of the TCM and OEM
harness.
2. Set up a frequency-capable digital multimeter, e.g. Fluke 87, to monitor frequency by selecting the
VOLTS-DC scale and depressing the HERTZ button once.
6–384
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
3. Connect the RED test lead to the solenoid low side pin at TCM breakout harness adapter J 47275. Connect the BLACK test lead to the isolated ground pin.
4. Using Allison DOC™ For PC–Service Tool solenoid test function to command the solenoid ON and
OFF.
5. Frequency should read in the KILOHERTZ range when the driver is commanded ON. Frequency should
read 0 hertz when the driver is commanded OFF.
Test Description
This DTC requires the use of the J 47275 TCM Breakout and J 47279 Transmission Breakout. The numbers below
refer to step numbers on the diagnostic table.
2. This step tests for the proper ignition voltage.
3. This step tests for an active DTC.
4. This step tests for wire-to-wire shorts in wire 137.
6. This step tests for the wire-to-wire shorts in the internal transmission harness.
DTC P2763 TCC PCS Control Circuit High
Step
1
2
3
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
1. Install the Allison DOC™ For PC–Service Tool. 9–18V (12V TCM)
18–32V (24V TCM)
2. Start the engine.
3. Record the failure records.
4. Monitor ignition voltage.
Is the voltage within the specified values?
1. Clear the DTC.
2. Start the engine and test drive the vehicle.
3. Attempt to duplicate the same conditions
observed in the failure records (range attained,
temperature, etc.).
Yes
Go to Step 2
Go to Step 3
Go to Step 4
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Resolve voltage
problem
Go to
Diagnostic Aids
NOTE: This DTC is intended to detect a short-tobattery condition in the TCC solenoid electrical
circuit.
Did DTC P2763 return?
Copyright © 2005 General Motors Corp.
6–385
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2763 TCC PCS Control Circuit High (cont’d)
Step
4
5
6
Action
NOTE: Review Section 4—Wire Test Procedures
before performing steps.
1. Turn OFF the ignition.
2. Disconnect the TCM 80-way connector.
3. Install the OEM-side of the 80-way connector to
the J 47275 TCM Breakout. Leave the TCM
disconnected.
4. Disconnect the transmission 20-way connector.
5. Inspect the routing of wire 137 in the chassis
harness between the TCM and the transmission
connector.
6. At J 47275-1 TCM Overlay, test for wire-to-wire
shorts between pin 37 and all other pins in the
80-way connector, and shorts-to-ground between
pin 37 and chassis ground.
Were any wire-to-wire shorts found?
NOTE: The vehicle OEM has responsibility for all
external wiring harness repairs. Harness repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Value(s)
Coordinate with the vehicle OEM to repair or
replace the vehicle wiring.
Is the repair complete?
1. Turn OFF the ignition.
2. Install J 47279 Transmission Breakout to the
transmission 20-way connector. Leave the OEM
harness disconnected.
3. Using a DVOM, test for wire-to-wire shorts
between pin 12 and all other pins in the 20-way
connector.
Yes
Go to Step 5
No
Go to Step 6
Go to Step 11
Go to Step 7
Go to Step 10
Go to Step 8
Go to Step 9
NOTE: The resistance value between pins 12 and
11 will read normal solenoid resistance. The
resistance value between pins 12 and 17 (7-speed
models) will be twice normal solenoid resistance.
Refer to the Solenoid Resistance chart for these
values.
7
8
9
6–386
Were any wire-to-wire shorts found?
1. Remove the hydraulic control module assembly.
2. Inspect the internal harness for wire-to-wire
shorts.
Were any wire-to-wire shorts found?
Repair or replace the internal wiring harness.
Is the repair complete?
Replace solenoid TCC.
Is the replacement complete?
Copyright © 2005 General Motors Corp.
Go to Step 11
Go to Step 11
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2763 TCC PCS Control Circuit High (cont’d)
Step
10
11
Action
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
Value(s)
Refer to TCM diagnostic procedure, Section 3–6.
Is Section 3–6 complete?
In order to verify your repair:
1. Clear the DTC.
2. Drive the vehicle under normal operating
conditions.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 11
No
Begin the
diagnosis again.
Go to Step 1
System OK
6–387
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2764 TCC PCS Control Circuit Low
END VIEW OF
20-WAY CONNECTOR
END VIEW OF
80-WAY CONNECTOR
1
6
7
10
11
14
15
20
61
80
41
60
21
40
1
20
TRANSMISSION
HSD3
TCC
SS2
TCM
11
12
17
WIRE 131
WIRE 137
WIRE 119
(7-SPEED MODELS)
31
HSD3
V BATTERY
37
19
15
RTDR ACCUM
HSD3
SS2
B
A
WIRE 131
WIRE 119
RTDR OR
DIFF LOCK (T-CASE)
HSD3
PCS5
B
A
WIRE 131
WIRE 115
V09068.00.00
Circuit Description
Torque Converter Clutch Pressure Control Solenoid (TCC) is a normally closed (N/C) solenoid used to apply the
torque converter clutch when specific engine and turbine speed conditions are met. The TCM commands the
solenoid ON to produce hydraulic pressure in the torque converter clutch apply circuit. When solenoid TCC is
commanded OFF, torque converter clutch pressure is released.
The TCM sends control current to solenoid TCC from High Side Driver 3 (HSD3) via wire 131. HSD3 is
continuously ON unless the TCM detects a fault condition. The TCM regulates the amount of current to TCC by
switching TCC’s Low Side Driver (LSD) ON and OFF. Wire 137 completes the circuit between TCC and its LSD.
DTC P2764 indicates that the TCM has detected a short-to-ground condition in the low side of solenoid TCC’s
electrical circuit.
6–388
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2764 TCC PCS Control Circuit Low
Conditions for Running the DTC
• The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater
than 9V and less than 32V (24V TCM).
•
TCM initialization is in process or engine speed is greater than 200 rpm and less than 7500 rpm for 5 seconds.
Conditions for Setting the DTC
DTC P2764 is set when the TCM detects a short-to-ground in the TCC solenoid return circuit for more than
2 seconds.
Actions Taken When the DTC Sets
When DTC P2764 is active, the following conditions will occur:
• The CHECK TRANS light illuminates.
• DTC is stored in TCM history.
• The TCM allows operation in second through sixth range, and Neutral and Reverse.
• The TCM inhibits TCC operation.
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
• DTC P2764 indicates a short-to-ground in the electrical circuit for the TCC solenoid.
•
You may have to drive the vehicle in order to experience a fault. Use the data obtained from failure records to
determine transmission range and/or certain vehicle operating variables such as temperature, run time etc. This
data can be useful in reproducing the failure mode when DTC was set.
•
Inspect the wiring for poor electrical connections at the TCM and transmission connector. Look for the
following conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
Inspect OEM wiring harness routing, look for possible contact points where chafing could occur leading to an
open or short circuit condition. Moving parts on the vehicle could be contacting the harness; this includes
parking brake drum, suspension components, etc.
•
•
When diagnosing for an intermittent short or open, massage the wiring harness while watching the test
equipment for a change.
•
Advanced Troubleshooting (requires a frequency-capable digital multimeter)—measure solenoid LSD
functionality as follows:
1. Install TCM breakout harness adapter J 47275 between the 80-way connectors of the TCM and OEM
harness.
2. Set up a frequency-capable digital multimeter, e.g. Fluke 87, to monitor frequency by selecting the
VOLTS-DC scale and depressing the HERTZ button once.Connect the RED test lead to the solenoid
Copyright © 2005 General Motors Corp.
6–389
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
low side pin at TCM breakout harness adapter J 47275. Connect the BLACK test lead to the isolated
ground pin.
3. Use Allison DOC™ For PC–Service Tool solenoid test function to command the solenoid ON and OFF.
4. Frequency should read in the KILOHERTZ range when the driver is commanded ON. Frequency should
read 0 hertz when the driver is commanded OFF.
Test Description
This DTC requires the use of the J 47275 TCM Breakout and J 47279 Transmission Breakout. The numbers below
refer to step numbers on the diagnostic table.
2. This step tests for the proper ignition voltage.
3. This step tests for an active DTC.
4. This step tests for wire-to-wire shorts or a short-to-ground condition in wire 137.
6. This step tests for the wire-to-wire shorts in the transmission internal harness.
DTC P2764 TCC PCS Control Circuit Low
Step
1
2
3
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
1. Install the Allison DOC™ For PC–Service Tool. 9–18V (12V TCM)
18–32V (24V TCM)
2. Start the engine.
3. Record the failure records.
4. Monitor ignition voltage.
Is the voltage within the specified values?
1. Clear the DTC.
2. Start the engine and test drive the vehicle.
3. Attempt to duplicate the same conditions
observed in the failure records (range attained,
temperature, etc.).
NOTE: This DTC is intended to detect a short-toground condition in the TCC solenoid electrical
circuit.
Did DTC P2764 return?
6–390
Copyright © 2005 General Motors Corp.
Yes
Go to Step 2
Go to Step 3
Go to Step 4
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Resolve voltage
problem
Go to
Diagnostic Aids
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2764 TCC PCS Control Circuit Low (cont’d)
Step
4
5
6
Action
NOTE: Review Section 4—Wire Test Procedures
before performing steps.
1. Turn OFF the ignition.
2. Disconnect the TCM 80-way connector.
3. Install the OEM-side of the 8-way connector to
the J 47275 TCM Breakout. Leave the TCM
disconnected.
4. Disconnect the transmission 20-way connector.
5. Inspect the routing of wire 131 and wire 137 in
the chassis harness between the TCM and the
transmission connector.
6. At J 47275-1 TCM Overlay, test for wire-to-wire
shorts between pin 37 and all other pins in the
80-way connector, and shorts-to-ground between
pin 37 and chassis ground.
7. Test wire 131 for an intermittent short. Refer to
Diagnostic Aids, Bullet 5 for the correct
procedure.
Were any wire-to-wire shorts or short-to-ground
found?
NOTE: The vehicle OEM has responsibility for all
external wiring harness repairs. Harness repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Value(s)
Yes
Go to Step 5
No
Go to Step 6
Go to Step 11
Coordinate with the vehicle OEM to repair or
replace the vehicle wiring.
Is the repair complete?
1. Turn OFF the ignition.
2. Install J 47279 Transmission Breakout to the
transmission 20-way connector. Leave the OEM
harness disconnected.
3. Using a DVOM, test for wire-to-wire shorts
between pin 12 and all other pins in the 20-way
connector, and shorts-to-ground between pin 12
and chassis ground.
Go to Step 7
Go to Step 10
Go to Step 8
Go to Step 9
NOTE: The resistance value between pins 12 and
11 will read normal solenoid resistance. The
resistance value between pins 12 and 17 will be
twice normal solenoid resistance.
7
Were any wire-to-wire shorts or shorts-to-ground
found?
1. Remove the hydraulic control module assembly.
2. Inspect the internal harness for wire-to-wire
shorts, or shorts-to-ground.
Were any wire-to-wire shorts or shorts-to-ground
found?
Refer to Solenoid
Resistance Chart
(Appendix K)
Copyright © 2005 General Motors Corp.
6–391
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2764 TCC PCS Control Circuit Low (cont’d)
Step
8
9
10
11
6–392
Action
Repair or replace the internal wiring harness.
Is the repair complete?
Replace solenoid TCC.
Is the replacement complete?
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
Value(s)
Refer to TCM diagnostic procedure, Section 3–6.
Is Section 3–6 complete?
In order to verify your repair:
1. Clear the DTC.
2. Drive the vehicle under normal operating
conditions.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 11
No
Go to Step 11
Go to Step 11
Begin the
diagnosis again.
Go to Step 1
System OK
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P278A Kickdown Input Failed ON
END VIEW OF
80-WAY CONNECTOR
61
80
41
60
21
40
1
20
CLOSED THROTTLE
ALL ITEMS SHOWN,
EXCEPT TCM, ARE
CUSTOMER-FURNISHED
THROTTLE
PEDAL
OPTIONAL
CUSTOMER
FURNISHED
VEHICLE
INTERFACE
WIRING
CONNECTOR
TCM
22
3
FULL THROTTLE
ECONOMY
SHIFT POINTS
ENGINE
OPERATING
RANGE
FULL THROTTLE
KICKDOWN
SHIFT POINTS PEDAL MOVEMENT BEYOND
THIS POINT MUST NOT
CHANGE ENGINE FUEL
MOMENTARY
SETTING OR TRANSMISSION
SWITCH
THROTTLE POSITION
WIRE 122 KICKDOWN
WIRE 103 SIGNAL RETURN
V09142.00.00
Circuit Description
The Transmission Control Module (TCM) can be calibrated to receive an acceleration pedal kickdown input from
either an analog input wire or the digital data link. When the operator activates the kickdown feature in the
Economy Mode, the TCM uses Performance shift points. A momentary, normally open switch attached to the
throttle pedal typically generates the kickdown input signal. The switch provides a detente feel when full-throttle is
achieved. When the operator “steps through” the detente, the kickdown function is activated.
Conditions for Running the DTC
•
•
The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater
than 9V and less than 32V (24V TCM).
The components are powered and engine speed is greater than 200 rpm and less than 750 rpm for 5 seconds.
Conditions for Setting the DTC
DTC P278A sets if the TCM is calibrated to receive the kickdown input signal and both of the following conditions
are met:
•
Throttle percentage is less than 20 percent.
•
The kickdown input signal is ON for more than 5 seconds.
Copyright © 2005 General Motors Corp.
6–393
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P278A Kickdown Input Failed ON
Actions Taken When the DTC Sets
When DTC P278A is active, the following conditions will occur:
•
The CHECK TRANS light does not illuminate.
•
DTC is stored in TCM history.
•
TCM inhibits Kickdown operation.
Conditions for Clearing the DTC/CHECK TRANS light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
• When analog input wires are used, the kickdown function is active when a switch is closed to complete the
circuit between wire 122 and signal return wire 103. If a data link is used, the TCM receives “accelerator pedal
kickdown input” as part of J1939 message parameters PGN 61443, Electronic Engine Controller 2 (EEC2).
•
•
•
DTC P278A indicates the TCM has detected a kickdown input signal for more than 5 seconds with less than
full throttle conditions. The code can be caused by:
— Faulty wiring
— Faulty connections to the accelerator pedal kickdown switch
— A faulty accelerator pedal kickdown switch
— Another controller improperly broadcasting kickdown signal on the data link when throttle conditions are
not met
— A faulty TCM.
Inspect the wiring for poor electrical connections at the TCM and kickdown input switch. Look for the
following conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
J1939 Kickdown status can be read on Allison DOC™ For PC–Service Tool. Monitor data link
communications using Data Bus Viewer.
Test Description
This DTC requires the use of the J 47275 TCM Breakout. The numbers below refer to step numbers on the
diagnostic table.
2. This step tests for an active DTC.
4. This step tests for status of analog input wire 122.
5. This step determines if kickdown function activated by a data link message.
6. This step tests for shorts-to-ground in wire 122.
7. This step tests for proper kickdown switch function.
9. This step monitors received messages on the digital data link.
6–394
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P278A Kickdown Input Failed ON
Step
1
2
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
1.
2.
3.
4.
Value(s)
Install the Allison DOC™ For PC–Service Tool.
Start the engine.
Record the failure records.
Clear the DTC and drive the vehicle. Attempt to
duplicate same operating conditions observed in
failure records.
Yes
Go to Step 2
Go to Step 3
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Go to
Diagnostic Aids
NOTE: This DTC indicates that the kickdown input
signal is present for more than 5 seconds when
throttle is below 20 percent.
3
4
5
6
7
Did DTC P278A return?
Inspect vehicle for analog kickdown input wire 122.
Is analog input wire 122 present?
1. Turn ON the ignition.
2. Using Allison DOC™ For PC–Service Tool,
observe status of Kickdown input wire 122.
Does wire 122 go ON when throttle pedal is
depressed and go OFF when throttle pedal is
released?
Using Allison DOC™ For PC–Service Tool, observe
status of Kickdown function?
NOTE: If Kickdown function is ON while the
Kickdown input wire 122 is OFF, the TCM is
receiving a “Kickdown Input-Active” message via
the data link.
Is the Kickdown function ON when wire 122 is
OFF?
1. Turn OFF the ignition.
2. Disconnect the TCM 80-way connector.
3. Install the OEM-side of the 80-way connector to
J 47275 TCM Breakout. Leave the TCM-side
disconnected.
4. Check for shorts-to-ground on wire 122.
Were any shorts or wiring defects found?
1. Turn OFF the ignition.
2. Using a DVOM, check for continuity when
switch is depressed and no continuity when
switch is released.
Does the switch close when depressed and open
when released?
Copyright © 2005 General Motors Corp.
Go to Step 4
Go to Step 9
Go to Step 5
Go to Step 6
Go to Step 9
Go to
Diagnostic Aids
Go to Step 8
Go to Step 7
Go to Step 9
Go to Step 8
6–395
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P278A Kickdown Input Failed ON (cont’d)
Step
8
9
10
11
6–396
Action
NOTE: The vehicle OEM has responsibility for all
external wiring harness repairs. Harness repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Value(s)
Coordinate with the vehicle OEM to repair or
replace the vehicle wiring.
Is the repair complete?
1. Turn ON the ignition.
2. Reconnect the 80-way connector, if removed in
Step 5.
3. Install Allison DOC™ For PC–Service Tool.
4. Turn ON the ignition.
5. Using Allison DOC™ For PC–Service Tool Data
Bus Viewer, observe status of AP Kickdown
Switch. Consult Allison DOC™ For PC–Service
Tool User’s Guide for instructions on using Data
Bus Viewer.
On Data Bus Viewer, does AP Kickdown Switch
show ON when throttle pedal is depressed and OFF
when throttle pedal is released?
NOTE: Allison Transmission is not responsible for
data link messages that originate in other
controllers. Repairs not associated with the
transmission controller are not covered by Allison
Transmission warranty.
Coordinate with the vehicle or engine OEM to
correct the cause of the inconsistent kickdown
switch status message.
Is the repair complete?
In order to verify your repair:
1. Clear the DTC.
2. Use Allison DOC™ For PC–Service Tool to
monitor retarder request percentage.
3. Drive the vehicle under conditions noted in the
failure records.
4. Confirm with the service tool in the test passed
section that the diagnostic test was run.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 11
No
Go to
Diagnostic Aids
Go to Step 10
Go to Step 11
Begin the
diagnosis again.
Go to Step 1
System OK
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2793 Gear Shift Direction Circuit
END VIEW OF
80-WAY CONNECTOR
61
80
41
60
21
40
1
20
3
13
12
8
ALLISON
4th GENERATION
CONTROLS
J1939 BASED
SHIFT SELECTOR
15
14
DIMMER INPUT
BATTERY VOLTAGE
IGNITION SENSE
J1939 HIGH
J1939 LOW
J1939 SHIELD
JUMPER INSTALLED IF
INTERNAL TERMINATION
RESISTOR IS USED
16
7
11
5
6
WIRE 134
TCM
34
DWM DIRECTIONAL INPUT
BATTERY GROUND
SECONDARY SHIFT SELECTOR ID
V09139.00.00
Circuit Description
Allison 4th Generation Controls shift selectors communicate with the transmission control module (TCM) by
exchanging standardized digital messages over the SAE J1939 controller area network (CAN). The shift selectors
are also equipped with a single wire backup to the J1939 CAN data link. Allison 4th Generation shift selectors
transmit directional information (Forward, Neutral, and Reverse) in the form of an analog pulse-width modulated
(PWM) signal via wire 134 to the TCM. The shift selector switches an internal driver ON and OFF to vary the duty
cycle of the voltage on wire 134. When the driver in the shift selector is ON, the voltage on wire 134 is pulled to
ground. When the driver is OFF, the driver’s output is open and the voltage on wire 134 is high. Since duty cycle is
measured when voltage is high, the driver’s OFF-time determines the duty cycle. For example, if wire 134 duty cycle
is 15 percent, the shift selector driver is ON (pulled low) 85 percent of the time and OFF (open) 15 percent of the
time.
Conditions for Running the DTC
The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater than
9V and less than 32V (24V TCM).
Copyright © 2005 General Motors Corp.
6–397
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2793 Gear Shift Direction Circuit
Conditions for Setting the DTC
DTC P2793 sets when the TCM has received invalid data from the shift selector.
Actions Taken When the DTC Sets
When DTC P2793 is active, the following conditions will occur:
•
The CHECK TRANS light illuminates.
•
DTC is stored in TCM history.
•
The TCM ignores PWM signal from shift selector.
•
If CAN is also lost, the TCM will lock in last valid direction.
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
•
DTC P2793 is usually caused by an intermittent electrical defect in wire 134. Common causes include:
— An intermittent open in wire 134 between the shift selector and the TCM.
— An intermittent short-to-battery or short-to-ground in wire 134.
— A poor connection at the shift selector or the TCM.
— A defective shift selector.
•
Inspect PWM signal wire 134 for poor electrical connections at the shift selector(s). Look for the following
conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
•
The PWM signal characteristics are shown in Table 6–18. When the vehicle is equipped with a primary and
secondary shift selector, the TCM receives a PWM signal from the active shift selector only.
Table 6–18. PWM Signal Characteristics
Description
Unknown
Park
Reverse
Neutral
Forward
Error
6–398
Primary Shift Selector
Secondary Shift Selector
977 Hz 10 Hz
871 Hz 10 Hz
(when active)
(when active)
Duty Cycle (Percent)
15% ± 2%
15% ± 2%
30% ± 2%
30% ± 2%
45% ± 2%
45% ± 2%
60% ± 2%
60% ± 2%
75% ± 2%
75% ± 2%
90% ± 2%
90% ± 2%
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
Test Description
This DTC requires the use of the J 47275 TCM Breakout. The number below refers to step numbers on the
diagnostic table.
2. This step tests for wiring defects between the TCM and the active shift selector.
DTC P2793 Gear Shift Direction Circuit
Step
1
2
3
4
5
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
1. Turn OFF the ignition.
2. Disconnect the 80-way connector at the TCM.
3. Connect the OEM 80-way connector to J 47275
TCM Breakout. Leave the TCM disconnected.
4. Disconnect the shift selector(s).
5. Inspect wire 134 between the TCM and shift
selector(s) for defects.
6. At J 47275-1 TCM Overlay, test pin 34 for wireto-wire shorts, and shorts-to-ground, and opens
between the TCM and shift selector. Massage the
harness while making the wiring checks.
Were any wiring defects found?
1. Verify ignition is OFF.
2. Reconnect the TCM and OEM 80-way
connectors.
3. Disconnect the shift selector (s), if not
disconnected in Step 2 above.
4. Using a digital multimeter (DVOM), test for
continuity between pin 5 in the OEM shift
selector connector and battery ground.
Is there a clean ground to the shift selector?
NOTE: The vehicle OEM has responsibility for all
external wiring harness repairs. Harness repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Coordinate with the vehicle OEM to repair or
replace the vehicle wiring.
Is the repair complete?
NOTE: If the vehicle has a primary and secondary
shift selector, both must be disconnected to properly
perform this step.
1. Disconnect the shift selector(s).
2. Turn ON the ignition. Leave the engine OFF.
3. Using a DVOM set on VDC, measure the voltage
on pin 11 in the OEM shift selector connector.
Is voltage within specified values?
Yes
Go to Step 2
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Go to Step 4
Go to Step 3
Go to Step 5
Go to Step 4
Go to Step 8
4.5–5.0V
Copyright © 2005 General Motors Corp.
Go to Step 7
Go to Step 6
6–399
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2793 Gear Shift Direction Circuit (cont’d)
Step
6
7
8
6–400
Action
Replace the affected shift selector.
Is the replacement complete?
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
Value(s)
Refer to TCM diagnostic procedure, Section 3–6.
Is Section 3–6 complete?
In order to verify your repair:
1. Clear the DTC.
2. Refer to Allison DOC™ For PC–Service Tool
“Test Passed” section and confirm the test was
run.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 8
No
Go to Step 8
Begin the
diagnosis again.
Go to Step 1
System OK
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2808 Pressure Control Solenoid 6 (PCS6) Stuck Off
Refer to Hydraulic Schematic
Circuit Description
The Transmission Control Module (TCM) uses input from the turbine speed and the output speed sensors to detect
if a clutch is slipping. Pressure Control Solenoid 6 (PCS6) supplies hydraulic pressure to the C6 clutch in Low
range for 7-speed models. The TCM sets a DTC P2808 when it detects a slip condition while PCS6 is supplying
hydraulic pressure to the oncoming clutch.
Conditions for Running the DTC
•
Hydraulic system is pressurized.
•
Output speed greater than or equal to 125 rpm.
•
Turbine speed greater than or equal to 60 rpm.
•
Cold Mode operation not required.
Conditions for Setting the DTC
DTC P2808 sets when the TCM detects an incorrect oncoming ratio (range-to-range) for an accumulated number
of occurrences.
Actions Taken When the DTC Sets
•
When DTC P2808 occurs, the TCM commands previous range.
•
While Diagnostic Response is active, the TCM ignores shift selector input.
•
The CHECK TRANS light illuminates.
•
DTC is stored in TCM history.
•
The TCM inhibits TCC engagement.
•
The TCM freezes shift adapts (DNA).
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
•
This DTC indicates that the oncoming clutch controlled by PCS6 is not applied or applied too slowly. Common
causes include:
— Erratic turbine or output speed signals.
— A leak or obstruction in the C6 clutch apply circuit.
— A defective solenoid.
— A stuck PCS6 regulator valve.
•
PCS6 supplies hydraulic pressure to C6 clutch in Low range for 7-speed models. Check the Allison DOC™
For PC–Service Tool failure record data for previous or current range information when the DTC was set to
determine which clutch circuit is suspect.
Copyright © 2005 General Motors Corp.
6–401
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
•
If the condition is intermittent, connect Allison DOC™ For PC–Service Tool and observe the speed sensor
indicated by the code. If the signal is erratic, investigate and eliminate the following:
— Intermittent wiring connection
— Excessive vibration (driveline or engine torsionals)
— Irregular sensor gap (loose sensor, loose tone wheel, or damaged tone wheel).
Test Description
The numbers below refer to step numbers on the diagnostic table.
2. This step tests for proper transmission fluid level.
3. This step tests for active diagnostic codes.
4. This step tests ignition voltage.
5. This step tests speed sensor readings.
6. This step tests for C6 clutch pressure from PCS6.
7. This step tests for evidence of clutch failure.
8. This step tests for stuck or sticking valves and damaged valve body gaskets.
DTC P2808 Pressure Control Solenoid 6 (PCS6) Stuck Off
Step
1
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
2
Perform the Fluid Checking Procedure (refer to
appropriate mechanic’s tips).
Is the transmission fluid level correct?
1. Install the Allison DOC™ For PC–Service Tool.
2. Turn ON the ignition, leave engine OFF.
3. Record the failure records.
4. Clear the DTC.
5. Drive the vehicle. Attempt to duplicate same
operating conditions observed in failure records.
3
Value(s)
Yes
Go to Step 2
Go to Step 3
Go to Step 4
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Go to Fluid Check
Procedure (refer to
mechanic’s tips)
Go to
Diagnostic Aids
NOTE: This DTC indicates that the TCM has
detected a slip condition and could not verify the
correct oncoming ratio following a shift.
4
5
6–402
Did DTC P2808 return?
1. Install the Allison DOC™ For PC–Service Tool. 9–18V (12V TCM)
Go to Step 5
18–32V (24V TCM)
2. Start the engine.
3. Record the DTC Failure Record data.
4. Using the Allison DOC™ For PC–Service Tool,
measure ignition voltage.
Is the voltage within the specified value?
1. Start the engine and drive the vehicle under
Watch for erratic
Go to the
normal operating conditions.
appropriate speed
speed sensor
sensor DTC
2. Using Allison DOC™ For PC–Service Tool,
signals
monitor turbine, engine, and output speed sensor
readings using the strip chart display.
Is speed sensor data erratic or are dropouts in signal
indicated?
Copyright © 2005 General Motors Corp.
Go to General
Troubleshooting
Section 8
Go to Step 6
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2808 Pressure Control Solenoid 6 (PCS6) Stuck Off (cont’d)
Step
6
7
8
9
10
11
Action
1. Turn OFF the ignition.
2. Install 2000 kPa (300 psi) pressure gauges in
main and C6 pressure taps.
3. Start the engine.
4. Using Allison DOC™ For PC–Service Tool,
select the clutch test mode.
5. With brakes applied, select and attain the range
where the DTC occurred as indicated in the
Failure Records.
6. Read and record Main and C6 clutch pressures.
Are the pressure readings within specified values in
Appendix B?
Remove the dipstick and inspect the transmission
fluid for clutch debris or burnt odor. If necessary,
drain a small amount of fluid for this inspection.
Are there signs of a clutch failure?
1. Consult the appropriate service manual and
remove the transmission hydraulic control
module.
2. Inspect the control valve body for stuck or
sticking solenoid regulator valves.
3. Inspect the suction filter. Ensure screen is not
plugged.
4. Inspect for damaged gaskets and face seals.
Was a valve body problem found and repaired?
Replace PCS6.
Is the replacement complete?
Remove the main and lube filters and inspect for
clutch debris. It may also be necessary to remove the
control module and inspect the suction screen for
clutch debris.
If debris is found, remove the transmission for
overhaul or replacement (refer to the appropriate
service manual).
Is the replacement complete?
In order to verify your repair:
1. Clear the DTC.
2. Using Allison DOC™ For PC–Service Tool,
monitor engine, turbine and output speed sensor
readings.
3. Drive the vehicle under normal operating
conditions.
Did the DTC return?
Value(s)
Refer to Main and
Clutch Pressure
specifications in
Appendix B
Copyright © 2005 General Motors Corp.
Yes
Go to Step 7
No
Go to Step 8
Go to Step 10
Go to
Diagnostic Aids
Go to Step 11
Go to Step 9
Go to Step 11
Go to Step 11
Begin the
diagnosis again.
Go to Step 1
System OK
6–403
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2809 Pressure Control Solenoid 6 (PCS6) Stuck On
Refer to Hydraulic Schematic
Circuit Description
The Transmission Control Module (TCM) uses information from the turbine and output speed sensors to detect if a
clutch is in a tie-up condition or if three clutches are applied. Pressure Control Solenoid 6 (PCS6) supplies
hydraulic pressure to the C6 clutch in Low range for 7-speed models. The TCM sets a DTC P2809 when it detects
a tie-up condition while PCS6 is supplying hydraulic pressure to the off-going clutch.
Conditions for Running the DTC
•
Hydraulic system is pressurized.
•
Output speed greater than or equal to 200 rpm.
•
Turbine speed greater than or equal to 200 rpm.
•
Cold Mode operation not required.
Conditions for Setting the DTC
DTC P2809 sets when the transmission is shifting from range to range and the off-going range (ratio) remains
engaged even though the off-going clutch is commanded OFF.
Actions Taken When the DTC Sets
•
When DTC P2809 occurs, the TCM will command previous range.
•
While Diagnostic Response is active, the TCM ignores shift selector inputs.
•
The CHECK TRANS light illuminates.
•
DTC is stored in TCM history.
•
The TCM inhibits TCC engagement.
•
The TCM freezes shift adapts (DNA).
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
•
This DTC indicates that the off-coming clutch controlled by PCS6 is not released or released too slowly.
Common causes include:
— Erratic turbine and output speed sensor readings.
— An obstruction in the C6 clutch exhaust circuit.
— A defective PCS6 solenoid.
— A stuck PCS6 regulator valve.
•
PCS6 supplies hydraulic pressure to C6 clutch in Low range for 7-speed models. Check the Allison DOC™
For PC–Service Tool failure record data for previous or current range information when the DTC was set to
determine which clutch circuit is suspect.
6–404
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
•
If the condition is intermittent, connect Allison DOC™ diagnostic tool and observe the speed sensor indicated
by the code. If the signal is erratic, investigate and eliminate the following:
— Intermittent wiring connection
— Excessive vibration (driveline or engine torsionals)
— Irregular sensor gap (loose sensor, loose tone wheel, or damaged tone wheel).
Test Description
The numbers below refer to step numbers on the diagnostic table.
2. This step tests for proper transmission fluid level.
3. This step tests for active diagnostic codes.
4. This step tests ignition voltage.
5. This step tests speed sensor readings.
6. This step tests for C6 clutch pressure from PCS6.
7. This step tests for evidence of clutch failure.
8. This step tests for stuck or sticking valves and damaged valve body gaskets.
DTC P2809 Pressure Control Solenoid 6 (PCS6) Stuck On
Step
1
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
2
Perform the Fluid Checking Procedure (refer to
appropriate mechanic’s tips).
Is the transmission fluid level correct?
1. Install the Allison DOC™ For PC–Service Tool.
2. Turn ON the ignition, leave engine OFF.
3. Record the failure records.
4. Clear the DTC.
5. Drive the vehicle. Attempt to duplicate same
operating conditions observed in failure records.
3
Value(s)
Yes
Go to Step 2
Go to Step 3
Go to Step 4
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Go to Fluid Check
Procedure (refer to
mechanic’s tips)
Go to
Diagnostic Aids
NOTE: This DTC indicates that the TCM has
detected that the off-going clutch did not release
(clutch tie-up) following a shift.
4
5
Did DTC P2809 return?
1. Install the Allison DOC™ For PC–Service Tool. 9–18V (12V TCM)
Go to Step 5
18–32V (24V TCM)
2. Start the engine.
3. Record the DTC failure record data.
4. Using the Allison DOC™ For PC–Service Tool,
measure ignition voltage.
Is the voltage within the specified value?
1. Start the engine and drive the vehicle under
Watch for erratic
Go to the
normal operating conditions.
appropriate speed
speed sensor
sensor DTC
2. Using Allison DOC™ For PC–Service Tool,
signals
monitor turbine, engine, and output speed sensor
readings using the strip chart display.
Is speed sensor data erratic or are dropouts in signal
indicated?
Copyright © 2005 General Motors Corp.
Go to General
Troubleshooting
Section 8
Go to Step 6
6–405
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2809 Pressure Control Solenoid 6 (PCS6) Stuck On (cont’d)
Step
6
7
8
9
10
11
6–406
Action
1. Turn OFF the ignition.
2. Install 2000 kPa (300 psi) pressure gauges in
main and C6 pressure taps.
3. Start the engine.
4. Using Allison DOC™ For PC–Service Tool,
select the clutch test mode.
5. With brakes applied, select and attain the range
where the DTC occurred as indicated in the
failure records.
6. Read and record Main and C6 clutch pressures.
Are the pressure readings within specified values in
Appendix B?
Remove the dipstick and inspect the transmission
fluid for clutch debris or burnt odor. If necessary,
drain a small amount of fluid for this inspection.
Are there signs of a clutch failure?
1. Consult the service manual and remove the
transmission hydraulic control module.
2. Inspect the control valve body for stuck or
sticking solenoid regulator valves.
3. Inspect the suction filter. Be sure screen is not
plugged.
4. Inspect for damaged gaskets and face seals.
Was a valve body problem found and repaired?
Replace PCS6.
Is the replacement complete?
Value(s)
Refer to Main and
Clutch Pressure
specifications in
Appendix B
Remove the main and lube filters and inspect for
clutch debris. It may also be necessary to remove the
control module and inspect the suction screen for
clutch debris.
If debris is found, remove the transmission for
overhaul or replacement (refer to the appropriate
service manual).
Is the replacement complete?
In order to verify your repair:
1. Clear the DTC.
2. Using Allison DOC™ For PC–Service Tool,
monitor engine, turbine and output speed sensor
readings.
3. Drive the vehicle under normal operating
conditions.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 7
No
Go to Step 8
Go to Step 10
Go to
Diagnostic Aids
Go to Step 11
Go to Step 9
Go to Step 11
Go to Step 11
Begin the
diagnosis again.
Go to Step 1
System OK
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2812 Pressure Control Solenoid 6 (PCS6) Control Circuit Open
END VIEW OF
80-WAY CONNECTOR
END VIEW OF
20-WAY CONNECTOR
1
6
7
10
11
14
15
20
61
80
41
60
21
40
1
20
TRANSMISSION
TRANSID
HSD1
PCS4
PCS6
MAIN MOD
TCM
20
1
2
7
8
WIRE 176
WIRE 111
WIRE 155
WIRE 178
WIRE 174
76
11
TRANSID
HSD1
ANALOG
INTERFACE
55
78
V BATTERY
74
V09066.00.00
Circuit Description
Pressure Control Solenoid 6 (PCS6) is a normally closed (N/C) solenoid used to apply the C6 clutch in low range
(7-speed models only). The TCM commands the solenoid ON to produce hydraulic pressure in the clutch apply
circuit. When PCS6 is commanded OFF, the clutch pressure is released.
The TCM sends control current to PCS6 from High Side Driver 1 (HSD1) via wire 111. HSD1 is continuously ON
unless the TCM detects a fault condition. The TCM regulates the amount of current to PCS6 by switching PCS6
Low Side Driver (LSD) ON and OFF. Wire 178 completes the circuit between PCS6 and its LSD. DTC P2812
indicates that the TCM has detected an open condition in PCS6 electrical circuit. The open condition may exist in
the high side (wire 111) or low side (wire 178).
Conditions for Running the DTC
•
The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater
than 9V and less than 32V (24V TCM).
•
TCM initialization is in process or engine speed is greater than 200 rpm and less than 7500 rpm for 5 seconds.
Conditions for Setting the DTC
DTC P2812 is set when the TCM detects an open circuit on the PCS6 return circuit for more than 2 seconds.
Copyright © 2005 General Motors Corp.
6–407
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2812 Pressure Control Solenoid 6 (PCS6) Control Circuit Open
Actions Taken When the DTC Sets
When DTC P2812 is active, the following conditions will occur:
•
The CHECK TRANS light illuminates.
•
DTC is stored in TCM history.
•
Hydraulic default (SOL OFF) is commanded. The shift selector position and hydraulic state of latch valves
determines the range attained.
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
• DTC P2812 indicates an open in the electrical circuit for the PCS6 solenoid. In addition to PCS6, High Side
Driver HSD1 also supplies power to the Main Mod and PCS4 solenoids. If DTC P2812 is accompanied by
DTC P0960 (Main Mod solenoid open circuit) and/or DTC P2718 (PCS4 open circuit), the open is most likely
in the high side of the circuit.
•
You may have to drive the vehicle in order to experience a fault. Use the data obtained from failure records to
determine transmission range and/or certain vehicle operating variables such as temperature, run time etc. This
data can be useful in reproducing the failure mode when DTC was set.
•
Inspect the wiring for poor electrical connections at the TCM and transmission connector. Look for the
following conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
Inspect OEM wiring harness routing, look for possible contact points where chafing could occur leading to an
open or short circuit condition. Moving parts on the vehicle could be contacting the harness; this includes
parking brake drum, suspension components, etc.
•
•
When diagnosing for an intermittent short or open, massage the wiring harness while watching the test
equipment for a change.
Test Description
This DTC requires the use of the J 47275 TCM Breakout and J 47279 Transmission Breakout. The numbers below
refer to step numbers on the diagnostic table.
2. This step tests for the proper ignition voltage.
3. This step tests for an active DTC.
4. This step tests the OEM harness for an excessive voltage drop caused by an open condition in either wire
111 or wire 178 of the OEM chassis harness.
6. This step tests for an open condition in the transmission internal harness.
7. This step tests for the proper PCS6 resistance.
6–408
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2812 Pressure Control Solenoid 6 (PCS6) Control Circuit Open
Step
1
2
3
4
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
1. Install the Allison DOC™ For PC–Service Tool. 9–18V (12V TCM)
18–32V (24V TCM)
2. Start the engine.
3. Record the failure records.
4. Monitor ignition voltage.
Is the voltage within the specified values?
1. Clear the DTC.
2. Start the engine and test drive the vehicle.
3. Attempt to duplicate the same conditions
observed in the failure records (range attained,
temperature, etc.).
NOTE: This DTC is intended to detect an open
condition in the PCS6 electrical circuit.
Did DTC P2812 return?
NOTE: Review Section 4—Wire Test Procedures
before performing steps.
1. Turn OFF the ignition.
2. Install J 47275 TCM Breakout between the OEM
and TCM 80-way connectors.
3. Install J 47279 Transmission Breakout between
the OEM and transmission 20-way connectors.
4. Turn ignition ON, leave engine OFF.
5. Using Allison DOC™ For PC–Service Tool, enter
Solenoid Test mode and command PCS6 ON.
6. Determine the voltage drop in the high side of the
PCS6 circuit as follows:
• At J 47275-1 TCM Overlay, measure voltage
between pin 11 and an isolated ground.
• At J 47279-1 Transmission Overlay, measure
voltage between pin 1 and isolated ground.
• Subtract the two voltage measurements to
obtain the voltage drop in the circuit.
7. Determine the voltage drop in the low side of the
PCS6 circuit as follows:
• At J 47275-1 TCM Overlay, measure voltage
between pin 78 and an isolated ground.
• At J 47279-1 Transmission Overlay, measure
voltage between pin 7 and isolated ground.
• Subtract the two voltage measurements to
obtain the voltage drop in the circuit.
NOTE: A voltage drop of more than 0.5V across
either circuit indicates an excessive voltage loss in
the OEM harness.
Yes
Go to Step 2
Go to Step 3
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Resolve voltage
problem
Go to Step 4
Go to
Diagnostic Aids
Go to Step 5
Go to Step 6
Did either high-side or low-side voltage drop exceed
0.5VDC?
Copyright © 2005 General Motors Corp.
6–409
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2812 Pressure Control Solenoid 6 (PCS6) Control Circuit Open (cont’d)
Step
5
6
7
8
9
10
11
6–410
Action
NOTE: The vehicle OEM has responsibility for all
external wiring harness repairs. Harness repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Coordinate with the vehicle OEM to repair or
replace the vehicle wiring.
Is the repair complete?
1. Turn OFF the ignition.
2. Disconnect the OEM 20-way connector from
J 47279 Transmission Breakout. Leave the
transmission 20-way connector connected to the
breakout.
3. Using a digital multimeter (DVOM), measure the
resistance between pin 1 and pin 7 of the
transmission 20-way connector.
Is the resistance within the specified value?
1. Remove the hydraulic control module assembly.
2. Disconnect PCS6 from the internal wiring
harness.
3. Using a DVOM, measure PCS6 resistance.
Is resistance within the specified values?
Replace the internal wiring harness.
Is the replacement complete?
Replace PCS6.
Is the replacement complete?
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
Value(s)
Yes
Go to Step 11
No
Refer to Solenoid
Resistance Chart
(Appendix K)
Go to Step 10
Go to Step 7
Refer to Solenoid
Resistance Chart
(Appendix K)
Go to Step 8
Go to Step 9
Refer to TCM diagnostic procedure, Section 3–6.
Is Section 3–6 complete?
In order to verify your repair:
1. Clear the DTC.
2. Drive the vehicle under conditions noted in
failure records.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Go to Step 11
Go to Step 11
Go to Step 11
Begin the
diagnosis again.
Go to Step 1
System OK
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2814 Pressure Control Solenoid 6 (PCS6) Control Circuit Low
END VIEW OF
80-WAY CONNECTOR
END VIEW OF
20-WAY CONNECTOR
1
6
7
10
11
14
15
20
61
80
41
60
21
40
1
20
TRANSMISSION
TRANSID
HSD1
PCS4
PCS6
MAIN MOD
TCM
20
1
2
7
8
WIRE 176
WIRE 111
WIRE 155
WIRE 178
WIRE 174
76
11
TRANSID
HSD1
ANALOG
INTERFACE
55
78
V BATTERY
74
V09066.00.00
Circuit Description
Pressure Control Solenoid 6 (PCS6) is a normally closed (N/C) solenoid used to apply the C6 clutch in low range
(7-speed models only). The TCM commands the solenoid ON to produce hydraulic pressure in the clutch apply
circuit. When PCS6 is commanded OFF, the clutch pressure is released.
The TCM sends control current to PCS6 from High Side Driver 1 (HSD1) via wire 111. HSD1 is continuously ON
unless the TCM detects a fault condition. The TCM regulates the amount of current to PCS6 by switching PCS6
Low Side Driver (LSD) ON and OFF. Wire 178 completes the circuit between PCS6 and its LSD. DTC P2814
indicates that the TCM has detected a short-to-ground condition in the low side of PCS6 electrical circuit.
Conditions for Running the DTC
•
The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater
than 9V and less than 32V (24V TCM).
•
TCM initialization is in process or engine speed is greater than 200 rpm and less than 7500 rpm for 5 seconds.
Conditions for Setting the DTC
DTC P2814 is set when the TCM detects a short-to-ground in the PCS6 return circuit for more than 2 seconds.
Copyright © 2005 General Motors Corp.
6–411
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2814 Pressure Control Solenoid 6 (PCS6) Control Circuit Low
Actions Taken When the DTC Sets
When DTC P2814 is active, the following conditions will occur:
•
The CHECK TRANS light illuminates.
•
DTC is stored in TCM history.
•
Hydraulic default (SOL OFF) is commanded. The shift selector position and hydraulic state of latch valves
determines the range attained.
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
•
DTC P2814 indicates a short-to-ground in the electrical circuit for the PCS6 solenoid.
•
You may have to drive the vehicle in order to experience a fault. Use the data obtained from failure records to
determine transmission range and/or certain vehicle operating variables such as temperature, run time etc. This
data can be useful in reproducing the failure mode when DTC was set.
•
Inspect the wiring for poor electrical connections at the TCM and transmission connector. Look for the
following conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
•
Inspect OEM wiring harness routing, look for possible contact points where chafing could occur leading to an
open or short circuit condition. Moving parts on the vehicle could be contacting the harness; this includes
parking brake drum, suspension components, etc.
•
When diagnosing for an intermittent short or open, massage the wiring harness while watching the test
equipment for a change.
•
Advanced Troubleshooting (requires a frequency-capable digital multimeter)—Measure solenoid LSD
functionality as follows:
1. Install TCM breakout harness adapter J 47275 between the 80-way connectors of the TCM and OEM
harness.
2. Set up a frequency-capable digital multimeter, e.g. Fluke 87, to monitor frequency by selecting the
VOLTS-DC scale and depressing the HERTZ button once.
3. Connect the RED test lead to the solenoid low side pin at TCM breakout harness adapter J 47275. Connect the BLACK test lead to the isolated ground pin.
4. Use Allison DOC™ For PC–Service Tool solenoid test function to command the solenoid ON and OFF.
5. Frequency should read in the KILOHERTZ range when the driver is commanded ON. Frequency should
read 0 hertz when the driver is commanded OFF.
6–412
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
Test Description
This DTC requires the use of the J 47275 TCM Breakout and J 47279 Transmission Breakout. The numbers below
refer to step numbers on the diagnostic table.
2. This step tests for the proper ignition voltage.
3. This step tests for an active DTC.
4. This step tests for wire-to-wire shorts or a short-to-ground condition in wire 178.
6. This step tests for the wire-to-wire shorts or a short-to-ground in the internal transmission harness.
DTC P2814 Pressure Control Solenoid 6 (PCS6) Control Circuit Low
Step
1
2
3
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
1. Install the Allison DOC™ For PC–Service Tool. 9–18V (12V TCM)
18–32V (24V TCM)
2. Start the engine.
3. Record the failure records.
4. Monitor ignition voltage.
Is the voltage within the specified values?
1. Clear the DTC.
2. Start the engine and test drive the vehicle.
3. Attempt to duplicate the same conditions
observed in the failure records (range attained,
temperature, etc.).
Yes
Go to Step 2
Go to Step 3
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Resolve voltage
problem
Go to Step 4
Go to
Diagnostic Aids
Go to Step 5
Go to Step 6
NOTE: This DTC is intended to detect short-toground condition in the PCS6 electrical circuit.
4
Did DTC P2814 return?
NOTE: Review Section 4—Wire Test Procedures
before performing steps.
1. Turn OFF the ignition.
2. Disconnect the TCM 80-way connector.
3. Install the OEM-side of the 80-way connector to
J 47275 TCM Breakout. Leave the TCM
disconnected.
4. Disconnect the transmission 20-way connector.
5. Inspect the routing of wire 178 in the chassis
harness between the TCM and the transmission
connector.
6. At J 47275-1 TCM Overlay, test for wire-to-wire
shorts between pin 78 and all other pins in the
80-way connector, and shorts-to-ground between
pin 78 and chassis ground.
Were any wire-to-wire shorts or shorts-to-ground
wiring defects found?
Copyright © 2005 General Motors Corp.
6–413
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2814 Pressure Control Solenoid 6 (PCS6) Control Circuit Low (cont’d)
Step
5
6
Action
NOTE: The vehicle OEM has responsibility for all
external wiring harness repairs. Harness repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Value(s)
Coordinate with the vehicle OEM to repair or
replace the vehicle wiring.
Is the repair complete?
1. Turn OFF the ignition.
2. Install J 47279 Transmission Breakout to the
transmission 20-way connector. Leave the OEM
harness disconnected.
3. Using a DVOM, test for wire-to-wire shorts
between pin 7 and all other pins in the 20-way
connector, and shorts-to-ground between pin 2
and chassis ground.
Yes
Go to Step 11
No
Go to Step 7
Go to Step 10
Go to Step 8
Go to Step 9
NOTE: The resistance value between pins 7 and 1,
and between pins 7 and 20 will read normal
solenoid resistance. The resistance value between
pins 7 and 2, and between 7 and 8 will be twice
normal solenoid resistance. Refer to the Solenoid
Resistance chart for these values.
7
8
9
10
11
6–414
Were any wire-to-wire shorts, or shorts-to-ground
found?
1. Remove the hydraulic control module assembly.
2. Inspect the internal harness for wire-to-wire
shorts, or shorts-to-ground.
Were any wire-to-wire shorts, or shorts-to-ground
found?
Replace the internal wiring harness.
Is the replacement complete?
Replace PCS6.
Is the replacement complete?
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
Refer to TCM diagnostic procedure, Section 3–6.
Is Section 3–6 complete?
In order to verify your repair:
1. Clear the DTC.
2. Drive the vehicle under conditions noted in
failure records.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Go to Step 11
Go to Step 11
Go to Step 11
Begin the
diagnosis again.
Go to Step 1
System OK
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2815 Pressure Control Solenoid 6 (PCS6) Control Circuit High
END VIEW OF
80-WAY CONNECTOR
END VIEW OF
20-WAY CONNECTOR
1
6
7
10
11
14
15
20
61
80
41
60
21
40
1
20
TRANSMISSION
TRANSID
HSD1
PCS4
PCS6
MAIN MOD
TCM
20
1
2
7
8
WIRE 176
WIRE 111
WIRE 155
WIRE 178
WIRE 174
76
11
TRANSID
HSD1
ANALOG
INTERFACE
55
78
V BATTERY
74
V09066.00.00
Circuit Description
Pressure Control Solenoid 6 (PCS6) is a normally closed (N/C) solenoid used to apply the C6 clutch in low range
(7-speed models only). The TCM commands the solenoid ON to produce hydraulic pressure in the clutch apply
circuit. When PCS6 is commanded OFF, the clutch pressure is released.
The TCM sends control current to PCS6 from High Side Driver 1 (HSD1) via wire 111. HSD1 is continuously ON
unless the TCM detects a fault condition. The TCM regulates the amount of current to PCS6 by switching PCS6
Low Side Driver (LSD) ON and OFF. Wire 178 completes the circuit between PCS6 and its LSD. DTC P2815
indicates that the TCM has detected a short-to-battery condition in the low side of PCS6 electrical circuit.
Conditions for Running the DTC
•
The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater
than 9V and less than 32V (24V TCM).
•
TCM initialization is in process or engine speed is greater than 200 rpm and less than 7500 rpm for 5 seconds.
Conditions for Setting the DTC
DTC P2815 is set when the TCM detects a short-to-battery in the PCS6 return circuit for more than 2 seconds.
Copyright © 2005 General Motors Corp.
6–415
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2815 Pressure Control Solenoid 6 (PCS6) Control Circuit High
Actions Taken When the DTC Sets
When DTC P2815 is active, the following conditions will occur:
•
The CHECK TRANS light illuminates.
•
DTC is stored in TCM history.
•
Hydraulic default (SOL OFF) is commanded. The shift selector position and hydraulic state of latch valves
determines the range attained.
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
•
DTC P2815 indicates a short-to-battery in the electrical circuit for the PCS6 solenoid.
•
You may have to drive the vehicle in order to experience a fault. Use the data obtained from failure records to
determine transmission range and/or certain vehicle operating variables such as temperature, run time etc. This
data can be useful in reproducing the failure mode when DTC was set.
•
Inspect the wiring for poor electrical connections at the TCM and transmission connector. Look for the
following conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
•
Inspect OEM wiring harness routing, look for possible contact points where chafing could occur leading to an
open or short circuit condition. Moving parts on the vehicle could be contacting the harness; this includes
parking brake drum, suspension components, etc.
•
When diagnosing for an intermittent short or open, massage the wiring harness while watching the test
equipment for a change.
•
Advanced Troubleshooting (requires a frequency-capable digital multimeter)—Measure solenoid Low Side
Driver functionality as follows:
1. Install TCM breakout harness adapter J 47275 between the 80-way connectors of the TCM and OEM
harness.
2. Set up a frequency-capable digital multimeter, e.g. Fluke 87, to monitor frequency by selecting the
VOLTS-DC scale and depressing the HERTZ button once.
3. Connect the RED test lead to the solenoid low side pin at TCM breakout harness adapter J 47275. Connect the BLACK test lead to the isolated ground pin.
4. Use Allison DOC™ For PC–Service Tool solenoid test function to command the solenoid ON and OFF.
5. Frequency should read in the KILOHERTZ range when the driver is commanded ON. Frequency should
read 0 hertz when the driver is commanded OFF.
6–416
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
Test Description
This DTC requires the use of the J 47275 TCM Breakout and J 47279 Transmission Breakout. The numbers below
refer to step numbers on the diagnostic table.
2. This step tests for the proper ignition voltage.
3. This step tests for an active DTC.
4. This step tests for wire-to-wire shorts between wire 178 and other wires in the OEM chassis harness.
6. This step tests for the wire-to-wire shorts in the transmission internal harness.
DTC P2815 Pressure Control Solenoid 6 (PCS6) Control Circuit High
Step
1
2
3
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
1. Install the Allison DOC™ For PC–Service Tool. 9–18V (12V TCM)
18–32V (24V TCM)
2. Start the engine.
3. Record the failure records.
4. Monitor ignition voltage.
Is the voltage within the specified values?
1. Clear the DTC.
2. Start the engine and test drive the vehicle.
3. Attempt to duplicate the same conditions
observed in the failure records (range attained,
temperature, etc.).
Yes
Go to Step 2
Go to Step 3
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Resolve voltage
problem
Go to Step 4
Go to
Diagnostic Aids
Go to Step 5
Go to Step 6
NOTE: This DTC is intended to detect short-tobattery condition in the PCS6 electrical circuit.
4
Did DTC P2815 return?
NOTE: Review Section 4—Wire Test Procedures
before performing steps.
1. Turn OFF the ignition.
2. Disconnect the TCM 80-way connector.
3. Install the OEM-side of the 80-way connector to
the J 47275 TCM Breakout. Leave the TCM
disconnected.
4. Disconnect the transmission 20-way connector.
5. Inspect the routing of wires 111 and 178 in the
chassis harness between the TCM and the
transmission connector.
6. At J 47275-1 TCM Overlay, test for wire-to-wire
shorts between pin 78 and all other pins in the
80-way connector.
Were any wire-to-wire shorts found?
Copyright © 2005 General Motors Corp.
6–417
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC P2815 Pressure Control Solenoid 6 (PCS6) Control Circuit High (cont’d)
Step
5
6
Action
NOTE: The vehicle OEM has responsibility for all
external wiring harness repairs. Harness repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Value(s)
Coordinate with the vehicle OEM to repair or
replace the vehicle wiring.
Is the repair complete?
1. Turn OFF the ignition.
2. Install J 47279 Transmission Breakout to the
transmission 20-way connector. Leave the OEM
harness disconnected.
3. Using a DVOM, test for wire-to-wire shorts
between pin 7 and all other pins in the 20-way
connector.
Yes
Go to Step 11
No
Go to Step 7
Go to Step 10
Go to Step 8
Go to Step 9
NOTE: The resistance value between pins 7 and 1,
and between pins 7 and 20 will read normal
solenoid resistance. The resistance value between
pins 7 and 2, and between 7 and 8 will be twice
normal solenoid resistance. Refer to the Solenoid
Resistance chart for these values.
7
8
9
10
11
6–418
Were any wire-to-wire shorts found?
1. Remove the hydraulic control module assembly.
2. Inspect the internal harness for wire-to-wire
shorts.
Were any wire-to-wire shorts found?
Replace the internal wiring harness.
Is the replacement complete?
Replace PCS6.
Is the replacement complete?
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
Refer to Solenoid
Resistance Chart
(Appendix K)
Refer to TCM diagnostic procedure, Section 3–6.
Is Section 3–6 complete?
In order to verify your repair:
1. Clear the DTC.
2. Drive the vehicle under conditions noted in
failure records.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Go to Step 11
Go to Step 11
Go to Step 11
Begin the
diagnosis again.
Go to Step 1
System OK
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC U0001 Hi Speed CAN Bus Reset Counter Overrun (IESCAN)
GROUND
TERMINATION
RESISTOR
CAN 2
IESCAN
26
6
27
126
INTERNAL TERMINATION RESISTOR
106
4
6
CAN 2 HIGH SIDE
127
CAN 2 LOW SIDE
14
16
POWER
SHIELD
67
66
47
167
SHIELD WIRE
166
CAN 2 BYPASS LOW SIDE
OPTION 1
TERMINATION RESISTOR
TCM
OPTION 2
(TCM PASS-THRU)
TCM
106
127
MODULE
OR DDL
S
S
167
SHIELD
MODULE
OR DDL
(CAN 2)
J1962
CONNECTOR
CAN 2 BYPASS HIGH SIDE
147
OPTION 3
INTERNAL TCM RESISTOR
TCM
106
127
MODULE
OR DDL
126
106
127
MODULE
OR DDL
167
166
147
MODULE
OR DDL
S
(CAN 2)
167
MODULE
OR DDL
(CAN 2)
V08981.02.00
Circuit Description
Beginnings in MY07, the Allison 4th Generation Controls transmission control module (TCM) is capable of
communicating with some Mercedes engines via the IESCAN. The TCM uses the high-speed Controller Area
Network 2 (CAN2) chip to exchange standardized messages with the engine controller and other vehicle systems.
The IESCAN physical network consists of a two-wire twisted pair, two 120 Ohm resistors and, in most cases, a
third shield wire. A 120 Ohm termination resistor is located at each end of the network. Vehicle OEMs may choose
to install external termination resistors or use internal termination resistors built into many IESCAN electronic
modules.
Conditions for Running the DTC
•
Ignition voltage is greater than 9V and less than 18V (12V TCM) or greater than 9V and less than 32V
(24V TCM).
•
Engine speed is greater than 200 rpm and less than 7500 rpm for 5 seconds.
Conditions for Setting the DTC
DTC U0001 sets when the TCM detects no communication on the CAN2 backbone for 3 seconds or more.
Copyright © 2005 General Motors Corp.
6–419
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC U0001 Hi Speed CAN Bus Reset Counter Overrun (IESCAN)
Actions Taken When the DTC Sets
When DTC U0001 is active, the following conditions will occur:
•
The TCM does not illuminate the CHECK TRANS light.
•
DTC is stored in TCM history.
•
SEM operation is not active, if applicable.
•
The TCM defaults to the most recent adaptive shift values and uses default throttle percentage.
•
TCM freezes shift adapts (DNA).
Conditions for Clearing the DTC/CHECK TRANS light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
• DTC U0001 indicates that a CAN bus hardware error has occurred. This may indicate a short-to-power or
short-to-ground exists in the CAN bus wiring harness.
•
•
•
•
Vehicle manufactures may use the following pin pairs for the J2284 CAN2 high and low wires:
— Pins 6 and 7
— Pins 66 and 47
— Both pins 6 and 27, and pins 66 and 47 in a “pass-through” setup.
As a result, vehicle manufactures can wire the TCM into the CAN2 backbone in three different ways:
— The TCM may be on its own stub as in traditional CAN backbones.
— The TCM may be wired in a “pass-through” configuration such that the CAN high and low wires are
connected to two separate pin pairs in the TCM 80-way connector. Data link messages pass-through but
can still be viewed by the TCM.
— The TCM may represent one end of the backbone. Typically, the internal resistor in the TCM will be used
in this setup.
Often an active U0001 will prevent the Allison DOC™ For PC–Service Tool from communicating with the
TCM. The J 47276 “T” Breakout and TCM Reflashing Harness may be used to confirm the TCM is
operational. Connect the T-harness to the TCM and leave the OEM harness disconnected. Provide input power
from the PCCS load box.
Inspect the J2284 CAN wires for poor electrical connections at the TCM. Look for the following conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
When diagnosing for an intermittent short or open, massage the wiring harness while watching the test
equipment for a change.
•
You may have to drive the vehicle in order to experience a fault.
•
For proper J2284 data link communications, it is necessary to have two 120 Ohm resistors installed in parallel
at the J2284 CAN backbone.
6–420
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
Test Description
This DTC requires the use of the J 47276 “T” Breakout and TCM Reflashing Harness. The numbers below refer to
step numbers on the diagnostic table.
2. This step tests for communication with the TCM via the vehicle diagnostic connector.
3. This step tests for communication with the TCM via the T-harness.
4. This step inspects for wiring defects in the CAN backbone.
DTC U0001 Hi Speed CAN Bus Reset Counter Overrun (IESCAN)
1
2
3
4
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
1. Connect Allison DOC™ For PC–Service Tool to
the vehicle’s diagnostic tool connector.
2. Turn ON the ignition. Leave the engine OFF.
Is the Allison DOC™ For PC–Service Tool
communicating with the TCM?
NOTE: Review Section 4—Wire Test Procedures
before performing steps.
1. Turn OFF the ignition.
2. Disconnect the TCM 80-way connector.
3. Install J 47276 “T” Breakout to the TCM. Leave
the OEM-side disconnected.
4. Provide power to the TCM from the J 47455-A
PCCS load box.
5. Connect Allison DOC™ For PC–Service Tool to
the 16-pin J1962 connector in the T-harness.
Is Allison DOC™ For PC–Service Tool
communicating with the TCM?
1. Turn OFF the ignition.
2. Inspect the CAN2 high, CAN2 low, and CAN2
shield wires at the engine and transmission
controllers for possible wire-to-wire shorts,
shorts-to-ground, or shorts-to-battery.
Yes
Go to Step 2
Go to
Diagnostic Aids
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Go to Step 3
Go to Step 4
Go to Step 6
Go to Step 5
Go to
Diagnostic Aids
NOTE: Vehicle manufactures may used the
following pin pairs for CAN high and CAN low.
• Pins 6 and 27
• Pins 66 and 47, or both pairs 6 and 27 and 66
and 47 in a “pass-through” setup.
Were any wiring defects found?
Copyright © 2005 General Motors Corp.
6–421
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC U0001 Hi Speed CAN Bus Reset Counter Overrun (IESCAN) (cont’d)
5
6
7
6–422
Action
NOTE: The vehicle OEM has responsibility for all
external wiring harness repairs. Harness repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Value(s)
Coordinate with the vehicle OEM to repair or
replace the vehicle wiring.
Is the repair complete?
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
Refer to TCM diagnostic procedure, Section 3–6.
Is Section 3–6 complete?
In order to verify your repair:
1. Install Allison DOC™ For PC–Service Tool.
2. If communication is established with the TCM,
use Allison DOC™ For PC–Service Tool to clear
the DTC.
3. Confirm the TCM can communicate with the
engine.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 7
No
Go to Step 7
Begin the
diagnosis again.
Go to Step 1
System OK
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC U0010 CAN Bus Reset Counter Overrun
TRANS (TCM)
ENGINE (ECM)
9-PIN DIAGNOSTIC
TOOL CONNECTOR
J1939
Data
Link
J1939
Data
Link
D
120 Ω
Resistor
E
F
C
A
H
7
NOTE 1
NOTE 2
SHIELD
SHIELD
Should not
exceed 1 meter
PIN E
PIN C (+)
SHIELD PIN D (–)
48 68 49 28 8
Pin ID
determined
by Engine
OEM
B
J
G
TERMINATION
RESISTOR
GREEN
120Ω
RESISTOR
SHIELD
SHIELD
SHIELD
SHIELD
120Ω
RESISTOR
CONTROLLER AREA NETWORK (CAN)
Should not exceed 40 meters
NOTE 1: JUMPER INSTALLATION IF INTERNAL TERMNATION RESISTOR IS USED.
NOTE 2: WIRES USED IN PASS-THROUGH CONFIGURATION.
V09132.00.00
Circuit Description
In Allison 4th Generation Controls, the preferred digital data link is the SAE J1939 Controller Area Network
(CAN). The TCM communicates with the engine control module and other controllers by exchanging standardized
digital messages over the SAE J1939 CAN. The physical network consists of a two-wire twisted pair, two 120 Ohm
termination resistors and, in most cases, a third shield wire. A 120 Ohm termination resistor is located at each end
of the network. Vehicle OEMs may chose to install external termination resistors or use internal termination
resistors built into many J1939 electronic modules.
Conditions for Running the DTC
• Ignition voltage is greater than 9V and less than 18V (12V TCM) or greater than 9V and less than 32V
(24V TCM).
•
Engine speed is greater than 200 rpm and less than 7500 rpm for 5 seconds.
Conditions for Setting the DTC
DTC U0010 sets when the TCM detects no communication on the CAN backbone for 3 seconds or more.
Copyright © 2005 General Motors Corp.
6–423
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC U0010 CAN Bus Reset Counter Overrun
Actions Taken When the DTC Sets
When DTC U0010 active, the following conditions will occur:
•
The TCM does not illuminate the CHECK TRANS light.
•
DTC is stored in TCM history.
•
SEM operation is not active, if applicable.
•
The TCM defaults to the most recent adaptive shifts values and uses default throttle percentage.
•
TCM freezes shift adapts (DNA).
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
•
DTC U0010 indicates that a CAN bus hardware error has occurred. This may indicate a short-to-power or
short-to-ground exists in the CAN bus wiring harness.
•
Vehicle manufacturers may use the following pin pairs for the J1939 CAN high and CAN low wires:
— Pins 8 and 28
— Pins 48 and 68
— Both Pins 8 and 28, and Pins 48 and 68 in a “pass-through” setup
•
As a result, vehicle manufacturers can wire the TCM into the CAN backbone in three different ways.
— The TCM may be on its own stub as in traditional CAN backbones.
— The TCM may be wired in a “pass-through” configuration such that the CAN high and low wires are
connected to two separate pin pairs in the TCM 80-way connector. Data link messages pass-through but
can still be viewed by the TCM.
— The TCM may represent one end of the backbone. Typically, the internal resistor in the TCM will be used
in this setup.
•
Often an active U0010 will prevent the Allison DOC™ For PC–Service Tool from communicating with the
TCM. The J 47276 “T” Breakout and TCM Reflashing Harness may be used to confirm that the TCM is
operational. Connect the T-harness to the TCM and leave the OEM harness disconnected. Provide input power
from the PCCS load box.
•
Inspect the J1939 CAN wires for poor electrical connections at the TCM. Look for the following conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
•
When diagnosing for an intermittent short or open, massage the wiring harness while watching the test
equipment for a change.
•
You may have to drive the vehicle in order to experience a fault.
•
For proper J1939 data link communications, it is necessary to have two 120 Ohm resistors installed in parallel
at the J1939 CAN backbone.
6–424
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
Test Description
This DTC requires the use of the J 47276 “T” Breakout and TCM Reflashing Harness. The numbers below refer to
step numbers on the diagnostic table.
2. This step tests for communication with the TCM via the vehicle diagnostic tool connector.
3. This step tests for communication with the TCM via the T-harness.
4. This step inspects for wiring defects in the CAN backbone.
DTC U0010 CAN Bus Reset Counter Overrun
Step
1
2
3
4
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
1. Connect Allison DOC™ For PC–Service Tool to
the vehicle’s diagnostic tool connector.
2. Turn ON the ignition. Leave the engine OFF.
Is Allison DOC™ For PC–Service Tool
communicating with the TCM?
1. Turn OFF the ignition.
2. Disconnect the 80-way connector at the TCM.
3. Install J 47276 “T” Breakout to the TCM. Leave
the OEM-side 80-way connector disconnected.
4. Provide power to the TCM from the J 42455-A
PCCS load box.
5. Connect Allison DOC™ For PC–Service Tool to
the 9-pin connector in the T-harness.
Is Allison DOC™ For PC–Service Tool
communicating with the TCM?
1. Turn OFF the ignition.
2. Inspect the CAN1 high, CAN1 low, and CAN1
Shield wires at the engine and transmission
controllers for possible wire-to-wire shorts,
shorts-to-ground, or shorts-to-battery.
Yes
Go to Step 2
Go to
Diagnostic Aids
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Go to Step 3
Go to Step 4
Go to Step 6
Go to Step 5
Go to
Diagnostic Aids
NOTE: Vehicle manufacturers may use the
following pin pairs for CAN high and CAN low:
• Pins 8 and 28
• Pins 48 and 68, or
• Both pairs (8 and 28), and (48 and 68) in a
“pass-through” setup.
5
Were any wiring defects found?
NOTE: The vehicle OEM has responsibility for all
external wiring harness repairs. Harness repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Go to Step 7
Coordinate with the vehicle OEM to repair or
replace the CAN wiring.
Is the repair complete?
Copyright © 2005 General Motors Corp.
6–425
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC U0010 CAN Bus Reset Counter Overrun (cont’d)
Step
6
7
6–426
Action
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
Value(s)
Refer to TCM diagnostic procedure, Section 3–6.
Is Section 3–6 complete?
In order to verify your repair:
1. Install Allison DOC™ For PC–Service Tool.
2. If communication is established with the TCM,
use Allison DOC™ For PC–Service Tool to clear
the DTC.
3. Confirm the TCM can communicate with the
engine.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 7
No
Begin the
diagnosis again.
Go to Step 1
System OK
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC U0100 Lost Communication with ECM/PCM (J1587)
REFER TO ELECTRICAL SCHEMATIC IN APPENDIX J
Circuit Description
In Allison 4th Generation Controls, the TCM is capable of communicating with the engine control module and
other controllers by exchanging standardized digital messages over the following data links:
•
SAE J1939 Controller Area Network (CAN)
•
SAE J1708/J1587 Serial Communications Interface
•
SAE J2284 High Speed CAN for use in IESCAN applications
The TCM sets a DTC U0100 when it stops receiving certain information (throttle position, coolant temperature, or
torque) from the engine controller via the J1587 serial communications interface.
Conditions for Running the DTC
• Ignition voltage is stable for a calibration time.
•
Ignition voltage is greater than 9V and less than 18V (12V TCM) or greater than 9V and less than 32V (24V
TCM).
Conditions for Setting the DTC
DTC U0100 sets when the TCM detects that no engine torque or throttle messages have being received from the
engine controller over the J1708/J1587 data link for 2 seconds or more.
Actions Taken when the DTC Sets
When DTC U0100 active, the following conditions will occur:
• The CHECK TRANS light illuminates.
• DTC is stored in TCM history.
• The TCM defaults to the most recent adaptive shifts values and uses default throttle percentage.
• TCM freezes shift adapts (DNA).
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the code from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
• The following condition points to an open in one of the serial communication interface wires at the Engine
Control Module:
— U0100 is active, and
— Allison DOC™ can view raw J1708/J1587 data from the TCM on data bus viewer when plugged into the
9-pin connector.
• Inspect the J1939 CAN wires for poor electrical connections at the TCM. Look for the following conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
Copyright © 2005 General Motors Corp.
6–427
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
•
When diagnosing for an intermittent short or open, massage the wiring harness while watching the test
equipment for a change.
•
You may have to drive the vehicle in order to experience a fault.
Test Description
2. This step tests for communications between the TCM and engine controller on the J1708/J1587 data link.
3. This step tests for communications between the TCM and engine controller using the J 47276 T-harness.
4. This step tests the J1708/J1587 serial communication interface wiring for open conditions or terminal
damage.
DTC U0100 Lost Communication with ECM/PCM (J1587)
Step
1
2
3
4
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
1. Connect Allison DOC™ For PC–Service Tool to
the vehicle’s diagnostic tool connector.
2. Turn ON the ignition. Leave the engine OFF.
3. Monitor Allison DOC™ For PC–Service Tool
Data Bus Viewer.
Can Allison DOC™ For PC–Service Tool read
J1708/J1587 information from the TCM on Data
Bus Viewer?
1. Turn OFF the ignition.
2. Disconnect the TCM 80-way connector.
3. Install the TCM-side of the 80-way connector to
the J 47276 “T” Breakout. Leave the OEM-side
disconnected.
4. Provide power to the TCM from the J 42455-A
PCCS load box.
5. Connect Allison DOC™ For PC–Service Tool to
the 9-pin connector in the T-harness.
Can Allison DOC™ For PC–Service Tool read
J1708/J1587 information from the TCM on Data
Bus Viewer?
1. Turn OFF the ignition.
2. Inspect the J1708/J1587 SCI wires at the TCM
and engine controller for possible open
conditions or terminal damage. Look for:
• Connector not locked at module.
• Terminal not locked in back shell.
• Chafing of insulation.
• Terminal damage or signs of corrosion.
Were any wiring defects found?
6–428
Copyright © 2005 General Motors Corp.
Yes
Go to Step 2
Go to Step 4
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Go to Step 3
Go to Step 4
Go to Step 7
Go to Step 5
Go to Step 6
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC U0100 Lost Communication with ECM/PCM (J1587) (cont’d)
Step
5
6
7
8
Action
NOTE: The vehicle OEM has responsibility for all
external wiring harness repairs. Harness repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Value(s)
Coordinate with the vehicle OEM to repair or
replace the vehicle wiring.
Is the repair complete?
Return the vehicle to the OEM for inspection of the
following:
1. The engine ECM is properly set to communicate
with an Allison TCM.
2. Proper pin location at the engine ECM.
3. Proper operation of the ECM.
Is the repair complete?
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
Refer to TCM diagnostic procedure, Section 3–6.
Is Section 3–6 complete?
In order to verify your repair:
1. Install Allison DOC™ For PC–Service Tool.
2. If communication is established with the TCM,
use Allison DOC™ For PC–Service Tool to clear
the DTC.
3. Confirm the TCM can communicate with the
engine.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Yes
Go to Step 8
No
Go to Step 8
Go to Step 8
Begin the
diagnosis again.
Go to Step 1
System OK
6–429
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC U0103 Lost Communication With Gear Shift Module (Shift Selector) 1
J1939 BASED
SHIFT SELECTOR
J1939
Data
Link
TRANS (TCM)
120Ω
Resistor
9-PIN DIAGNOSTIC
TOOL CONNECTOR
J1939
Data
Link
D
120Ω
Resistor
E
F
C
A
H
7
NOTE 2
Should not
exceed 1 meter
NOTE 3
PIN E
PIN C (+)
SHIELD PIN D (–)
48 68 49 28 8
NOTE 2
SHIELD
BATERY VOLTAGE
IGNITION SENSE
5 13 12 14 8 15 16 7
SHIELD
SECONDARY
SELECTOR 2 ID
BATTERY
GROUND NOTE 1
G
6
B
J
TERMINATION
RESISTOR
GREEN
120Ω
RESISTOR
SHIELD
SHIELD
SHIELD
SHIELD
120Ω
RESISTOR
CONTROLLER AREA NETWORK (CAN)
Should not exceed 40 meters
NOTE 1: REQUIRED FOR SELECTOR 2 OF DUAL SELECTOR INSTALLATIONS.
NOTE 2: JUMPER INSTALLATION IF INTERNAL TERMNATION RESISTOR IS USED.
NOTE 3: PASS-THROUGH CONFIGURATION SHOWN.
V09131.00.00
Circuit Description
Allison 4th Generation Controls shift selectors communicate with the transmission control module (TCM) by
exchanging standardized digital messages over the SAE J1939 Controller Area Network (CAN). The physical
network consists of a two-wire twisted pair, two 120 Ohm termination resistors and, in most cases, a third shield
wire. A 120 Ohm termination resistor is located at each end of the network to maintain good J1939 signal quality.
Vehicle OEMs may chose to configure the network to take advantage of 120 Ohm resistors built in to Allison
4th Generation Controls TCMs and shift selectors.
Conditions for Running the DTC
Ignition voltage is greater than 9V and less than 18V (12V TCM) or greater than 9V and less than 32V
(24V TCM).
Conditions for Setting the DTC
DTC U0103 sets when the TCM has not received a state of health (SOH) message from the primary shift selector
for 2 or more seconds.
6–430
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC U0103 Lost Communication With Gear Shift Module (Shift Selector) 1
Actions Taken When the DTC Sets
When DTC U0103 active, the following conditions will occur:
•
The CHECK TRANS light illuminates.
•
DTC is stored in TCM history.
•
The active shift selector will freeze the displays for 1.5 seconds, go blank for 10.5 seconds, then display cateyes, i.e. -\-, -\-.
•
Direction change shifts, i.e., forward to Reverse, etc., are allowed based on PWM signal from Allison shift
selectors.
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
•
Vehicle manufacturers can configure the controller area network to use a built-in termination resistor in Allison
shift selectors by installing a jumper between pins 7 and 18 at the primary shift selector connector. OEMs are
required to clearly indicate where internal termination resistors have been used.
•
DTC U0103 can be caused by the following conditions:
— An intermittent open between the shift selector and the connector node.
— A poor connection at the shift selector or the connector node.
— An intermittent open in the connector node.
— An open power or ground circuit to the shift selector.
— A defective shift selector.
•
Inspect the J1939 CAN wires for poor electrical connections at the primary shift selector. Look for the
following conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
Test Description
This DTC requires the use of the J 47275 TCM Breakout. The numbers below refer to step numbers on the
diagnostic table.
2. This step tests for proper power inputs to the primary shift selector.
3. This step tests for wiring defects between the primary shift selector and the connection to the J1939
backbone.
Copyright © 2005 General Motors Corp.
6–431
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC U0103 Lost Communication With Gear Shift Module (Shift Selector) 1
Step
1
2
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
Test the following primary shift selector circuits for
an open or short-to-ground:
1. The battery power supply including fuses, if
applicable.
2. The ignition sense circuit.
3. The ground return circuit.
Yes
Go to Step 2
Go to Step 6
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Go to Step 3
Go to Step 4
Go to Step 5
NOTE: DTC U0103 indicates the TCM did not
detect a state of health message from the primary
shift selector for 2 or more seconds. This may
indicate an open in shift selector wiring or a
defective shift selector.
3
4
Did you find and correct the condition?
1. Turn OFF the ignition.
2. Disconnect the 80-way connector at the TCM and
install J 47275 TCM Breakout.
3. Disconnect the shift selector(s).
4. Inspect the CAN backbone between the TCM and
shift selector(s) for defects.
5. At J 47275-1 TCM Overlay, test for wire-to-wire
shorts, and shorts-to-ground, and opens between
shift selector at pins 8 (CAN Lo1), 28 (CAN
Hi1), 48 (CAN Hi2), and 68 (CAN Lo2), if used.
6. At J 47275-1 TCM Overlay, test for wire-to-wire
shorts and opens between shift selector at pin 49
(CAN shield).
NOTE: If the TCM internal resistor is used, the
vehicle OEM will connect the wire 107 and wire 128
together in the external harness.
7. If TCM internal termination resistor is used, test
for opens, wire-to-wire shorts, and shorts-toground at pin 7 (internal resistor).
Were any wiring defects found?
NOTE: The vehicle OEM has responsibility for all
external wiring harness repairs. Harness repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Coordinate with the vehicle OEM to repair or
replace the vehicle wiring.
Is the repair complete?
6–432
Copyright © 2005 General Motors Corp.
Go to Step 6
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC U0103 Lost Communication With Gear Shift Module (Shift Selector) 1 (cont’d)
Step
5
6
Action
Replace the primary shift selector.
Is the replacement complete?
In order to verify your repair:
1. Install Allison DOC™ For PC–Service Tool.
2. Clear the DTC.
3. Verify the TCM responds to shift selector
commands.
4. Refer to Allison DOC™ For PC–Service Tool
“Test Passed” section and confirm the test was
run.
Did the DTC return?
Value(s)
Copyright © 2005 General Motors Corp.
Yes
Go to Step 6
No
Begin the
diagnosis again.
Go to Step 1
System OK
6–433
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC U0115 Lost Communication With ECM
TRANS (TCM)
ENGINE (ECM)
9-PIN DIAGNOSTIC
TOOL CONNECTOR
J1939
Data
Link
J1939
Data
Link
D
120 Ω
Resistor
E
F
C
A
G
H
7
NOTE 1
NOTE 2
SHIELD
SHIELD
Should not
exceed 1 meter
PIN E
PIN C (+)
SHIELD PIN D (–)
48 68 49 28 8
Pin ID
determined
by Engine
OEM
B
J
TERMINATION
RESISTOR
GREEN
120Ω
RESISTOR
SHIELD
SHIELD
SHIELD
SHIELD
120Ω
RESISTOR
CONTROLLER AREA NETWORK (CAN)
Should not exceed 40 meters
NOTE 1: JUMPER INSTALLATION IF INTERNAL TERMNATION RESISTOR IS USED.
NOTE 2: WIRES USED IN PASS-THROUGH CONFIGURATION.
V09132.00.00
Circuit Description
•
In Allison 4th Generation Controls, the TCM is capable of communicating with the engine control module and
other controllers by exchanging standardized digital messages over the following data links:
— SAE J1939 Controller Area Network (CAN)
— SAE J1708/J1587 Serial Communication Interface
— SAE J2284 High Speed CAN for use in IESCAN applications.
•
The TCM sets a DTC U0115 when it stops receiving certain information (throttle position, coolant
temperature, or torque) from the engine controller via the J1939 CAN.
Conditions for Running the DTC
•
Ignition voltage is stable for a calibration time.
•
Ignition voltage is greater than 9V and less than 18V (12V TCM) or greater than 9V and less than 32V
(24V TCM).
Conditions for Setting the DTC
DTC U0115 sets when the TCM detects that no engine torque or throttle messages have been received from the
engine controller over the J1939 for 2 seconds or more.
6–434
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC U0115 Lost Communication With ECM
Actions Taken When the DTC Sets
When DTC U0115 is active, the following conditions will occur:
•
The CHECK TRANS light illuminates.
•
DTC is stored in TCM history.
•
The TCM defaults to the most recent adaptive shifts values and uses default throttle percentage.
•
TCM freezes shift adapts (DNA).
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
•
Often an active U0115 will prevent the Allison DOC™ For PC–Service Tool from communicating with the
TCM. The J 47276 “T” Breakout and TCM Reflashing Harness may be used to confirm that the TCM is
operational. The T-harness is only useful to confirm that the TCM is able to communicate with Allison DOC™
diagnostic tool.
•
Vehicles that use SEM/LRTP may set a DTC U0115 when engine performance complaints are present. This
may include injector concerns that could cause an engine to default to a “fail safe” mode. Some engine
manufacturers may interrupt engine torque messaging, which will result in a DTC U0115. Inspect the engine
side for possible engine diagnostic codes that may indicate that this condition is present and correct before
performing further troubleshooting on DTC U0115.
•
The following condition points to an open in one of the CAN wires at the Engine Control Module:
— U0115 is active, and
— Allison DOC™ For PC–Service Tool can communicate with the TCM when plugged into the 9-pin
connector.
•
This DTC can be caused if engine ECM parameters are improperly set.
•
Inspect the J1939 CAN wires for poor electrical connections at the TCM. Look for the following conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
•
When diagnosing for an intermittent short or open, massage the wiring harness while watching the test
equipment for a change.
•
You may have to drive the vehicle in order to experience a fault.
•
For proper J1939 data link communications, it is necessary to have two 120 Ohm resistors installed in parallel
at the J1939 CAN backbone.
Copyright © 2005 General Motors Corp.
6–435
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
Test Description
This DTC requires the use of the J 47276 “T” Breakout and TCM Reflashing Harness. The numbers below refer to
step numbers on the diagnostic table.
2. This step tests for communications between the TCM and engine controller on the vehicle data link.
3. This step tests for communications between the TCM and the engine controller using the J 47276
“T” Breakout.
4. This step tests the J1939 CAN1 wiring for open conditions or terminal damage.
5. This step tests the J1939 CAN1 wiring for proper termination resistance value.
DTC U0115 Lost Communication With ECM/PCM (CAN)
Step
1
2
3
4
5
6–436
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
1. Connect Allison DOC™ For PC–Service Tool to
the vehicle’s diagnostic tool connector.
2. Turn ON the ignition. Leave the engine OFF.
Is Allison DOC™ For PC–Service Tool
communicating with the TCM?
1. Turn OFF the ignition.
2. Disconnect the TCM 80-way connector.
3. Install the TCM-side of the 80-way connector to
the J 47276 “T” Breakout and TCM Reflashing
Harness. Leave the OEM-side disconnected.
4. Provide power to the TCM from the J 42455 at
PCCS load box.
5. Connect Allison DOC™ For PC–Service Tool to
the 9-pin connector on the J 47276 “T” Breakout
and TCM Reflashing Harness.
Is Allison DOC™ For PC–Service Tool
communicating with the TCM?
1. Turn OFF the ignition.
2. Inspect the CAN1 high, CAN1 low, and CAN1
Shield wires at the engine and transmission
controllers for possible open conditions or
terminal damage. Look for the following:
• Connector stub not locked at module
• Terminal not locked in back shell
• Chafing of insulation
• Terminal damage or signs of corrosion.
Were any wiring defects found?
Using a DVOM, measure resistance between pins C
and D at the vehicle 9-pin diagnostic connector.
Did the resistance match the specified value?
60 Ohms
Copyright © 2005 General Motors Corp.
Yes
Go to Step 2
Go to Step 4
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Go to Step 3
Go to Step 4
Go to Step 9
Go to Step 7
Go to Step 5
Go to Step 8
Go to Step 6
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC U0115 Lost Communication With ECM/PCM (CAN) (cont’d)
Step
6
7
8
9
Action
NOTE: A resistance reading other than 60 Ohms
indicates that a termination resistor is missing or a
resistor with an improper value is installed. There
should be two 120 Ohms resistors wired in parallel
in the Controller Area Network.
Value(s)
Return the vehicle to the OEM for repair.
Is the repair complete?
NOTE: The vehicle OEM has responsibility for all
external wiring harness repairs. Harness repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Coordinate with the vehicle OEM to repair or
replace the vehicle wiring.
Is the repair complete?
Return the vehicle to the OEM for inspection of the
following:
1. The engine ECM is properly set to communicate
with the Allison TCM.
2. Proper pin location at the engine ECM.
3. Proper operation of the ECM.
Is the repair complete?
NOTE: In most cases, the TCM is not at fault.
Investigate thoroughly before replacing the TCM.
Yes
Go to Step 10
No
Go to Step 10
Go to Step 10
Go to Step 10
Refer to TCM diagnostic procedure, Section 3–6.
10
Is Section 3–6 complete?
In order to verify your repair:
1. Install Allison DOC™ For PC–Service Tool.
2. If communication is established with the TCM,
use Allison DOC™ For PC–Service Tool to clear
the DTC.
3. Confirm the TCM can communicate with the
engine.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Begin the
diagnosis again.
Go to Step 1
System OK
6–437
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC U0291 Lost Communication With Gear Shift Module (Shift Selector) 2
J1939 BASED
SHIFT SELECTOR
J1939
Data
Link
TRANS (TCM)
120Ω
Resistor
9-PIN DIAGNOSTIC
TOOL CONNECTOR
J1939
Data
Link
D
120Ω
Resistor
E
F
C
A
H
7
NOTE 2
Should not
exceed 1 meter
NOTE 3
PIN E
PIN C (+)
SHIELD PIN D (–)
48 68 49 28 8
NOTE 2
SHIELD
BATERY VOLTAGE
IGNITION SENSE
5 13 12 14 8 15 16 7
SHIELD
SECONDARY
SELECTOR 2 ID
BATTERY
GROUND NOTE 1
G
6
B
J
TERMINATION
RESISTOR
GREEN
120Ω
RESISTOR
SHIELD
SHIELD
SHIELD
SHIELD
120Ω
RESISTOR
CONTROLLER AREA NETWORK (CAN)
Should not exceed 40 meters
NOTE 1: REQUIRED FOR SELECTOR 2 OF DUAL SELECTOR INSTALLATIONS.
NOTE 2: JUMPER INSTALLATION IF INTERNAL TERMNATION RESISTOR IS USED.
NOTE 3: PASS-THROUGH CONFIGURATION SHOWN.
V09131.00.00
Circuit Description
Allison 4th Generation Controls shift selectors communicate with the transmission control module (TCM) by
exchanging standardized digital messages over the SAE J1939 Controller Area Network (CAN). The physical
network consists of a two-wire twisted pair, two 120 Ohm termination resistors and, in most cases, a third shield
wire. A 120 Ohm termination resistor is located at each end of the network to maintain good J1939 signal quality.
Vehicle OEMs may chose to configure the network to take advantage of 120 Ohm resistors built in to Allison
4th Generation Controls TCMs and shift selectors.
Conditions for Running the DTC
Ignition voltage is greater than 9V and less than 18V (12V TCM) or greater than 9V and less than 32V
(24V TCM).
Conditions for Setting the DTC
DTC U0115 sets when the TCM has not received a state of health (SOH) message from the secondary shift selector
for 2 or more seconds.
6–438
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC U0291 Lost Communication With Gear Shift Module (Shift Selector) 2
Actions Taken When the DTC Sets
When DTC U0291 active, the following conditions will occur:
•
The CHECK TRANS light illuminates.
•
DTC is stored in TCM history.
•
The active shift selector will freeze the displays for 1.5 seconds, go blank for 10.5 seconds, then display cateyes, i.e. -\-, -\-.
•
Direction change shifts i.e. forward to Reverse, etc are allowed based on PWM signal from Allison shift
selectors.
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
•
Vehicle manufacturers can configure the controller area network to use a built-in termination resistor in the
Allison shift selectors by installing a jumper between pins 7 and 18 at the secondary shift selector connector.
OEMs are required to clearly indicate where internal termination resistors have been used.
•
DTC U0291 can be caused by the following conditions:
— An intermittent open between the shift selector and the connector node.
— A poor connection at the shift selector or the connector node.
— An intermittent open in the connector node.
— An open power or ground circuit to the shift selector.
— A defective shift selector.
•
Inspect the J1939 CAN wires for poor electrical connections at the secondary shift selector. Look for the
following conditions:
— A bent terminal
— A backed-out terminal
— A damaged terminal
— Poor terminal tension
— A chafed wire
— A broken wire inside the insulation.
Test Description
This DTC requires the use of the J 47275 TCM Breakout. The numbers below refer to step numbers on the
diagnostic table.
2. This step tests for proper power inputs to the secondary shift selector.
3. This step tests for wiring defects between the secondary shift selector and the connection to the J1939
backbone.
Copyright © 2005 General Motors Corp.
6–439
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC U0291 Lost Communication With Gear Shift Module (Shift Selector) 2
Step
1
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
2
Test the following secondary shift selector circuits
for an open or short-to-ground:
1. The battery power supply including fuses, if
applicable.
2. The ignition sense circuit.
3. The ground return circuit.
Value(s)
Yes
Go to Step 2
Go to Step 6
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Go to Step 3
Go to Step 4
Go to Step 5
NOTE: DTC U0291 indicates the TCM did not
detect a state of health message from the secondary
shift selector for 2 or more seconds. This may
indicate an open in shift selector wiring or a
defective shift selector.
Did you find and correct the condition?
3
4
1. Turn OFF the ignition.
2. Disconnect the 80-way connector at the TCM and
install J 47275 TCM Breakout.
3. Disconnect the shift selector(s).
4. Inspect the CAN backbone between the TCM and
shift selector(s) for defects.
5. At J 47275-1 TCM Overlay, test for wire-to-wire
shorts, and shorts-to-ground, and opens between
shift selector at pins 8 (CAN Lo1), 28 (CAN
Hi1), 48 (CAN Hi2), and 68 (CAN Lo2), if used.
6. At J 47275-1 TCM Overlay, test for wire-to-wire
shorts and opens between shift selector at pin 49
(CAN shield).
NOTE: If the TCM internal resistor is used, the
vehicle OEM will connect wire 107 and wire 128
together in the external harness.
7. If TCM internal termination resistor is used, test
for opens, wire-to-wire shorts, and shorts-toground at pin 7 (internal resistor).
Were any wiring defects found?
NOTE: The vehicle OEM has responsibility for all
external wiring harness repairs. Harness repairs
performed by Allison Transmission distributors and
dealers are not covered by Allison Transmission
warranty.
Coordinate with the vehicle OEM to repair or
replace the vehicle wiring.
Is the repair complete?
6–440
Copyright © 2005 General Motors Corp.
Go to Step 6
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC U0291 Lost Communication With Gear Shift Module (Shift Selector) 2 (cont’d)
Step
5
6
Action
Replace the secondary shift selector.
Is the replacement complete?
In order to verify your repair:
1. Install Allison DOC™ For PC–Service Tool.
2. Clear the DTC.
3. Verify the TCM responds to shift selector
commands.
4. Refer to Allison DOC™ For PC–Service Tool
“Test Passed” section and confirm the test was
run.
Did the DTC return?
Value(s)
Copyright © 2005 General Motors Corp.
Yes
Go to Step 6
No
Begin the
diagnosis again.
Go to Step 1
System OK
6–441
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC U0304 Incompatible Gear Shift Module 1 (Shift Selector) ID
No Schematic for this DTC
Circuit Description
In Allison 4th Generation Controls, the TCM communicates with the shift selector over the J1939 controller area
network. Allison J1939 shift selectors broadcast proprietary messages to the TCM related to range selection and
other operating modes. The TCM sets a DTC U0304 when the primary shift selector is not an Allison shift selector
or on the approved list of shift selectors.
NOTE:
The presence of DTC U0304 indicates the primary shift selector is not on the approved list of shift
selectors. Contact the Allison Transmission Applications Engineering (1-800-252-5283) to obtain
approval to use the shift selector.
Conditions for Running the DTC
• Ignition voltage is greater than 9V and less than 18V (12V TCM) or greater than 9V and less than 32V
(24V TCM).
•
This test is run during the entire ignition cycle.
Conditions for Setting the DTC
DTC U0304 sets when the primary shift selector is not an Allison J1939-based shift selector, or on the approved list
of OEM-provided shift selectors.
Actions Taken when the DTC Sets
When DTC U0304 active, the following conditions will occur:
•
The CHECK TRANS light illuminates.
•
DTC is stored in TCM history.
•
The TCM ignores shift selector inputs.
•
TCM freezes shift adapts (DNA).
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the code from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
6–442
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC U0333 Incompatible Gear Shift Module 2 (Shift Selector) ID
No Schematic for this DTC
Circuit Description
In Allison 4th Generation Controls, the TCM communicates with the shift selector over the J1939 controller area
network. Allison J1939 shift selectors broadcast proprietary messages to the TCM related to range selection and
other operating modes. The TCM sets a DTC U0304 when the primary shift selector is not an Allison shift selector
or on the approved list of shift selectors.
NOTE:
The presence of DTC U0304 indicates the primary shift selector is not on the approved list of shift
selectors. Contact the Allison Transmission Applications Engineering (1-800-252-5283) to obtain
approval to use the shift selector.
Conditions for Running the DTC
• Ignition voltage is greater than 9V and less than 18V (12V TCM) or greater than 9V and less than 32V (24V
TCM).
•
This test is run during the entire ignition cycle.
Conditions for Setting the DTC
DTC U0304 sets when the primary shift selector is not an Allison J1939-based shift selector, or on the approved list
of OEM-provided shift selectors.
Actions Taken when the DTC Sets
When DTC U0304 active, the following conditions will occur:
•
The CHECK TRANS light illuminates.
•
DTC is stored in TCM history.
•
The TCM ignores shift selector inputs.
•
TCM freezes shift adapts (DNA).
Conditions for clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the code from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Copyright © 2005 General Motors Corp.
6–443
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC U0404 Invalid Data Received From Gear Shift Module (Shift Selector) 1
J1939 BASED
SHIFT SELECTOR
J1939
Data
Link
TRANS (TCM)
120Ω
Resistor
9-PIN DIAGNOSTIC
TOOL CONNECTOR
J1939
Data
Link
D
120Ω
Resistor
E
F
C
A
H
7
NOTE 2
Should not
exceed 1 meter
NOTE 3
PIN E
PIN C (+)
SHIELD PIN D (–)
48 68 49 28 8
NOTE 2
SHIELD
BATERY VOLTAGE
IGNITION SENSE
5 13 12 14 8 15 16 7
SHIELD
SECONDARY
SELECTOR 2 ID
BATTERY
GROUND NOTE 1
6
B
J
G
TERMINATION
RESISTOR
GREEN
120Ω
RESISTOR
SHIELD
SHIELD
SHIELD
SHIELD
120Ω
RESISTOR
CONTROLLER AREA NETWORK (CAN)
Should not exceed 40 meters
NOTE 1: REQUIRED FOR SELECTOR 2 OF DUAL SELECTOR INSTALLATIONS.
NOTE 2: JUMPER INSTALLATION IF INTERNAL TERMNATION RESISTOR IS USED.
NOTE 3: PASS-THROUGH CONFIGURATION SHOWN.
V09131.00.00
Circuit Description
Allison 4th Generation Controls shift selectors communicate with the transmission control module (TCM) by
exchanging standardized digital messages over the SAE J1939 Controller Area Network (CAN). The TCM sets a
DTC U0404 when it receives invalid data from the primary shift selector.
Conditions for Running the DTC
Ignition voltage is greater than 9V and less than 18V (12V TCM) or greater than 9V and less than 32V (24V TCM).
Conditions for Setting the DTC
DTC U0404 sets when the TCM detects invalid data from the shift selector.
Actions Taken When the DTC Sets
When DTC U0404 active, the following conditions will occur:
•
The CHECK TRANS light illuminates.
•
DTC is stored in TCM history.
•
The active shift selector will freeze the displays for 1.5 seconds, go blank for 10.5 seconds, then display cateyes, i.e. -\-, -\-.
•
Direction change shifts, i.e., forward to Reverse etc., are allowed based on PWM signal from Allison shift
selectors.
6–444
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC U0404 Invalid Data Received From Gear Shift Module (Shift Selector) 1
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
DTC U0404 is typically caused by a defective primary shift selector.
Test Description
The number below refers to step numbers on the diagnostic table.
2. This step tests for proper power inputs to the primary shift selector.
DTC U0404 Invalid Data Received From Gear Shift Module (Shift Selector) 1
Step
1
2
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
Value(s)
Test the following primary shift selector circuits for
an open or short-to-ground:
1. The battery power supply including fuses, if
applicable.
2. The ignition sense circuit.
3. The ground return circuit.
Yes
Go to Step 2
Go to Step 4
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Go to Step 3
NOTE: DTC U0404 indicates the TCM did not
detect valid data from the primary shift selector.
This may indicate an open in shift selector wiring or
a defective shift selector.
3
4
Did you find and correct the condition?
Replace the primary shift selector.
Is the replacement complete?
In order to verify your repair:
1. Install Allison DOC™ For PC–Service Tool.
2. Clear the DTC.
3. Verify the TCM responds to shift selector
commands.
4. Refer to Allison DOC™ For PC–Service Tool
“Test Passed” section and confirm the test was
run.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Go to Step 4
Begin the
diagnosis again.
Go to Step 1
System OK
6–445
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC U0592 Invalid Data Received From Gear Shift Module (Shift Selector) 2
J1939 BASED
SHIFT SELECTOR
J1939
Data
Link
TRANS (TCM)
120Ω
Resistor
9-PIN DIAGNOSTIC
TOOL CONNECTOR
J1939
Data
Link
D
120Ω
Resistor
E
F
C
A
H
7
NOTE 2
Should not
exceed 1 meter
NOTE 3
PIN E
PIN C (+)
SHIELD PIN D (–)
48 68 49 28 8
NOTE 2
SHIELD
BATERY VOLTAGE
IGNITION SENSE
5 13 12 14 8 15 16 7
SHIELD
SECONDARY
SELECTOR 2 ID
BATTERY
GROUND NOTE 1
G
6
B
J
TERMINATION
RESISTOR
GREEN
120Ω
RESISTOR
SHIELD
SHIELD
SHIELD
SHIELD
120Ω
RESISTOR
CONTROLLER AREA NETWORK (CAN)
Should not exceed 40 meters
NOTE 1: REQUIRED FOR SELECTOR 2 OF DUAL SELECTOR INSTALLATIONS.
NOTE 2: JUMPER INSTALLATION IF INTERNAL TERMNATION RESISTOR IS USED.
NOTE 3: PASS-THROUGH CONFIGURATION SHOWN.
V09131.00.00
Circuit Description
Allison 4th Generation Controls shift selectors communicate with the transmission control module (TCM) by
exchanging standardized digital messages over the SAE J1939 Controller Area Network (CAN). The TCM sets a
DTC U0592 when it receives invalid data from the secondary shift selector.
Conditions for Running the DTC
Ignition voltage is greater than 9V and less than 18V (12V TCM) or greater than 9V and less than 32V (24V TCM).
Conditions for Setting the DTC
DTC U0592 sets when the TCM has detects invalid data from the shift selector.
Actions Taken When the DTC Sets
When DTC U0592 active, the following conditions will occur:
•
The CHECK TRANS light illuminates.
•
DTC is stored in TCM history.
•
The active shift selector will freeze the displays for 1.5 seconds, go blank for 10.5 seconds, then display cateyes, i.e. -\-, -\-.
•
Direction change shifts, i.e., forward to Reverse etc., are allowed based on PWM signal from Allison shift
selectors.
6–446
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
DIAGNOSTIC TROUBLE CODES (DTC)
DTC U0592 Invalid Data Received From Gear Shift Module (Shift Selector) 2
Conditions for Clearing the DTC/CHECK TRANS Light
The Allison DOC™ For PC–Service Tool can be used to clear the DTC from the TCM history. The TCM
automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
DTC U0592 is typically caused by a defective secondary shift selector.
Test Description
The number below refers to step numbers on the diagnostic table.
2. This step tests for proper power inputs to the secondary shift selector.
DTC U0592 Invalid Data Received From Gear Shift Module (Shift Selector) 2
Step
1
Action
Was Section 3–5, Beginning The Troubleshooting
Process, performed?
2
Test the following secondary shift selector circuits
for an open or short-to-ground:
1. The battery power supply including fuses, if
applicable.
2. The ignition sense circuit.
3. The ground return circuit.
Value(s)
Yes
Go to Step 2
Go to Step 4
No
Go to Section 3–5,
Beginning the
Troubleshooting
Process
Go to Step 3
NOTE: DTC U0592 indicates the TCM did not
detect valid data from the secondary shift selector.
This may indicate an open in shift selector wiring or
a defective shift selector.
3
4
Did you find and correct the condition?
Replace the secondary shift selector.
Is the replacement complete?
In order to verify your repair:
1. Install Allison DOC™ For PC–Service Tool.
2. Clear the DTC.
3. Verify the TCM responds to shift selector
commands.
4. Refer to Allison DOC™ For PC–Service Tool
“Test Passed” section and confirm the test was
run.
Did the DTC return?
Copyright © 2005 General Motors Corp.
Go to Step 4
Begin the
diagnosis again.
Go to Step 1
System OK
6–447
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
SECTION 7—INPUT AND OUTPUT FUNCTIONS
7–1.
INPUT FUNCTIONS
Input functions are signals sent into the TCM that prompt the TCM to take action. Input functions are activated and
deactivated by switched ignition power or ground (wire 103) to the TCM (wired through the VIW), or through the
MODE button on the shift selector. The following input functions can be activated using the MODE button:
•
•
•
•
Secondary Shift Schedule
D1 Selection (available with pushbutton selector only)
PTO Enable
Auto 2–1 Preselect for 7-Speeds
The wiring schematic in Appendix J illustrates installation requirements for input functions and designates specific
wire numbers in the transmission control system to be used for the activation of these input functions. Appendix J
should be used for reference only. The vehicle manufacturer determines which input functions are programmed,
which wires are used, and whether voltage input was positive or ground. Wiring schematics for input and output
functions are shown in Appendix P. Use Allison DOC™ For PC–Service Tool to determine which wire was
programmed for a particular input function and the wiring schematic can be consulted to find out if input to the
TCM is + or – voltage. Refer to Allison publication GN3433EN, User Guide for Allison DOC™ For PC–Service
Tool, for further information regarding special input functions and other inhibits.
NOTE:
The wiring schematic in Appendix J shows the intended use of the control features specified. These
features have only been validated in the configuration shown. ANY USE OF THESE FEATURES
WHICH DIFFERS FROM WHAT IS SHOWN IS NOT THE RESPONSIBILITY OF ALLISON
TRANSMISSION.
CAUTION:
NEVER use chassis ground as an INPUT FUNCTION ground. Chassis ground can
carry voltage potential of 1 or 2 volts above battery ground. This non-approved input
will “confuse” the TCM and cause erroneous input results. Be sure to use wire 103
which is signal ground.
Activating an input function can inhibit transmission operation in the same manner as a diagnostic code. Use the
Allison DOC™ For PC–Service Tool to verify an active input function or a diagnostic code inhibit. Refer to Allison
publication GN3433EN, User Guide for Allison DOC™ For PC–Service Tool, for further information regarding
special input functions and other inhibits. For more detailed information on input functions, refer to the Allison
Tech Data Book 4th Generation Controls and General Information.
The maximum number of input and output functions which may be used in any installation depends upon the
transmission model and its features. Refer to Table 7–1.
Table 7–1. Input/Output Function Availability
Transmission Model
6-Speed and
4000 7-Speed Transmissions
3000 7-Speed Transmissions
Auxiliary Transmission
Controls Functions
Number Of Input
Functions
Number Of Output
Functions
Retarder
12 + Mode Button
8
Transfer Case
12 + Mode Button
8
Copyright © 2005 General Motors Corp.
7–1
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
INPUT AND OUTPUT FUNCTIONS
The following input functions inhibit direction change shifts (forward to reverse or reverse to forward):
•
•
•
•
•
•
•
•
•
Auxiliary Function Range Inhibit (standard)
Auxiliary Function Range Inhibit (special)
Quick to Neutral, Pump Option
Automatic Neutral for PTO
Automatic Neutral at Stop
Reverse Enable
Automatic Neutral for Refuse Packers
Automatic Neutral for Refuse Packers with Service Brake Input
Direction Change Enable
The following input functions lock the transmission in fourth range:
• Fire Truck Pump Mode
• Fourth Lockup Pump Mode
The following input functions preselect a lower range:
• Engine Brake and Preselect Request (standard)
• Engine Brake and Preselect Request (special)
The following input functions inhibit upshifts:
• D1 Selection
• Auxiliary Hold
The following input functions inhibit lockup shifts:
• Manual Lockup
• Anti-lock Brake Response
The following input function inhibits range and lockup shifts at high horsepower:
• Shift Enable/Shift in Process (Oil Field Application)
The following functions are general restrictions to normal operation:
•
•
•
•
•
•
•
•
•
High Input Speed causes neutral to range inhibit
Medium Cold Oil causes operation confined to R (Reverse), N (Neutral), and 2nd-range start
Hot Oil restricts operation to 4th-range maximum (except emergency applications)
Two Speed Axle Enable permits change only at low output speed and throttle
Special Pattern Logic monitors N or D or N to R shifts; if engine throttle or output speed is too high, the
transmission remains in N.
Wheel Lock disengages the lockup clutch and inhibits forward range downshifts and shifts to reverse
Anti-lock Brake Response deactivates the retarder and disengages the lockup clutch
High Throttle during N (Neutral) to any range shift causes a revised clutch pressure apply rate and turns
off shift adaptive
Power loss to the TCM restricts operation to certain ranges. Hydraulic default (SOL OFF) is commanded.
The shift selector position and hydraulic state of logic values determine the range attained.
The following input function limits operation to 1st-range and N (Neutral):
• Refuse Vehicle Step Switch
7–2
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
INPUT AND OUTPUT FUNCTIONS
7–2.
OUTPUT FUNCTIONS
Output functions are signals sent out by the TCM that activate or control devices or mechanisms. These control
devices or mechanisms are controlled by relays or direct connection signals from the TCM.
Many input and output functions are closely related. For example, the PTO Enable option (input function) also
includes PTO Output wiring information. When searching for output function information, be sure to review any
related input function information references.
The wiring schematics in Appendix J and Appendix P illustrate installation requirements for output functions as
well as input functions and designate specific wire numbers in the transmission control system to be used for the
activation of these output functions. The wiring schematics in Appendix J should be used for reference only. Ask
the vehicle manufacturer which specific output functions are programmed and which wires are used. Output
function polarity is not significant when an Allison-supplied VIM is used. The Allison DOC™ For PC–Service Tool
can also be utilized to determine which wire was programmed for a particular output function. For more detailed
information on output functions, refer to Allison Tech Data, Allison 4th Generation Controls 3000 and 4000 Product
Families on the Allison Transmission Extranet. The schematics in Appendix P are from Allison Tech Data.
Copyright © 2005 General Motors Corp.
7–3
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
SECTION 8—GENERAL TROUBLESHOOTING OF PERFORMANCE COMPLAINTS
IMPORTANT:
Determine the following before beginning specific troubleshooting, removing the transmission, or removing
attached components.
• Are there active diagnostic codes?
• Is the lever shift selector lever in N (Neutral) to allow starting the engine?
• Is the battery properly connected and charged?
• Is isolated battery properly connected (if used)?
• Is the fluid level correct?
• Is voltage to the TCM correct?
• Is the engine properly tuned?
• Is fuel flow to the engine correct?
• Are wheel chocks in place?
• Is air flow to the cooler and radiator unrestricted?
• Is the driveline properly connected?
• Are there signs of fluid leakage under the vehicle? What is the origination point?
• Are hydraulic connections correctly made and not leaking?
• Is vehicle acceleration from a stop changed?
• Are electrical connections correctly made?
• Are there any other obvious vehicle or transmission problems?
• Are clutch pressures within specified limits?
Use the various sections of this manual to isolate the listed problems. The following charts address specific vehicle
complaints. Some complaints involve diagnostic codes, so all troubleshooting should involve determining if the
system has set any diagnostic codes.
Copyright © 2005 General Motors Corp.
8–1
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
GENERAL TROUBLESHOOTING OF PERFORMANCE COMPLAINTS
Table 8–1. Troubleshooting Performance Complaints
Problem
Probable Cause
Suggested Remedy
SHIFT SELECTOR DISPLAYS
“CATEYE” AND VEHICLE IS
NOT OPERABLE
No communication between the
TCM and a remote shift selector
Refer to code U0103 or U0291 in
Troubleshooting Procedure
SHIFT SELECTOR DISPLAY IS
BLANK
VIM fuse is blown
Replace VIM fuse
Fuse blown in OEM substitute
Replace VIM fuse
Failed CAN (J1939) Data Link
Should change to “cateye” (-\-)
within 12 seconds (see Code U0103
or U0291)
SHIFT SELECTOR NOT
LIGHTED AT NIGHT (WHEN
HEADLIGHTS ARE ON)
OEM input wire at pin 3 of shift
selector connector not connected or
improperly connected
Find wire at pin 3 and connect it or
install it, if necessary
VEHICLE WILL NOT START
(ENGINE WILL NOT CRANK)
Lever shift selector not in N (Neutral) Select N (Neutral) and restart
All display segments of display
lighted
8–2
Dead battery
Recharge battery
Disconnected battery
Reconnect battery
Faulty starter circuit
Repair vehicle starter circuit
Faulty neutral start relay
Replace neutral start relay
Faulty wiring in neutral start circuit
Repair wiring
Calibration programmed to J 1939
neutral start message (neutral start
relay not used)
Troubleshoot J1939 wiring
(CAN link)
Voltage to TCM too low
Measure battery and charging
system voltage
Faulty ignition wire (163)
Repair wire 163
Faulty lever shift selector
Replace lever shift selector
Lack of battery voltage on Circuit
141 from TCM when in neutral
Repair Circuit 141 or replace TCM
Shift selector in initialization
(approximately 2 seconds)
None, normal
Faulty TCM
Replace the TCM
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
GENERAL TROUBLESHOOTING OF PERFORMANCE COMPLAINTS
Table 8–1. Troubleshooting Performance Complaints (cont’d)
Problem
Probable Cause
Suggested Remedy
CHECK TRANS LIGHT WILL
NOT GO OUT AT START-UP
A. Vehicle Drives Normally
B. Vehicle Does Not Drive
CHECK TRANS LIGHT
FLASHES INTERMITTENTLY
NO CHECK TRANS LIGHT AT
IGNITION
Faulty CHECK TRANS light,
relay, or circuit
Replace relay or repair circuit
An LED rather than a lamp is
installed for the CHECK TRANS
light and the LED is partially
lighted from leakage current
Install a lamp rather than an LED
for the CHECK TRANS light
Engine does not start
Repair engine starting system
Faulty harness
Repair harness (Section 4 and
Appendix E)
Faulty interface wiring to vehicle
electrical system
Repair wiring (Appendix E)
Faulty TCM
Replace the TCM
Intermittent power to TCM
Test input power to the TCM and
correct if necessary
Loose wiring to CHECK TRANS
light
Repair wiring
Faulty or incorrect ground wire
attachment
Repair ground circuit
Intermittent opening in Circuit 129
Repair Circuit 129
Faulty light bulb or socket
Replace light bulb or socket
Incorrect wiring to and from
CHECK TRANS light bulb
Repair wiring (Appendix E)
Faulty wiring harness
Inspect wiring between TCM and
CHECK TRANS light, and repair
where necessary (Appendix E)
Circuit 129 open
Repair Circuit 129
Vehicle wired for J1939 CHECK
TRANS light but calibration
doesn’t support that message
Reprogram with correct calibration
Faulty TCM
Replace TCM
Copyright © 2005 General Motors Corp.
8–3
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
GENERAL TROUBLESHOOTING OF PERFORMANCE COMPLAINTS
Table 8–1. Troubleshooting Performance Complaints (cont’d)
Problem
Probable Cause
Suggested Remedy
TCM WILL NOT TURN OFF
WHEN IGNITION SWITCH OFF
Faulty ignition switch
Replace ignition switch
Externally-generated speed sensor
signal(s)—refer to Appendix L for
detailed inspection
Find source of false speed sensor
signal(s) and correct problem
TRANSMISSION WILL NOT
SHIFT TO FORWARD OR
REVERSE (STAYS IN
NEUTRAL)
Engine rpm too high*
Reduce engine rpm. Also, it may be
necessary to reselect N (Neutral)
and then D (Drive) or R (Reverse).
Low fluid level
Add fluid to proper level. Refer to
appropriate transmission
mechanic’s tips for proper dipstick
calibration.
Throttle position sensor or linkage
is not functioning properly*
Refer to throttle position sensor for
correct set-up (Appendix F)
Voltage to TCM too low*
Test vehicle battery and charging
system
Shift selector is not functioning
properly
Replace shift selector
Disconnected or dirty connectors
Perform connector checkout
(Appendix E)
Faulty wiring harnesses
Repair harness (Appendix E)
Speed sensor(s) not functioning
properly*
Repair or replace speed sensor(s) or
circuitry. Refer to appropriate
transmission service manual and
Appendix E.
Faulty TCM
Replace the TCM
Input function wire open and
“auxiliary function range inhibit”,
or “direction change enable” in the
calibration*
Test input function programming
with Allison DOC For PC–
Service Tool. Correct wiring or
switch problem which does not
allow input function wire to be
grounded.
“Auxiliary Function Range
Inhibit-Standard” or “direction
change enable”—hooked up to
brake pressure*
Apply brakes with high force
* Flashing digital display on shifter.
8–4
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
GENERAL TROUBLESHOOTING OF PERFORMANCE COMPLAINTS
Table 8–1. Troubleshooting Performance Complaints (cont’d)
Problem
TRANSMISSION WILL NOT
STAY IN FORWARD OR
REVERSE
TRANSMISSION WILL NOT
MAKE A SPECIFIC SHIFT
TRANSMISSION LOCKUP
CLUTCH WILL NOT ENGAGE
Probable Cause
Suggested Remedy
Auto-neutral or quick-to-neutral
circuit (input function) faulty
Repair quick-to-neutral circuit
Leaking at solenoid assembly
Rebuild solenoid assembly. Refer
to appropriate transmission service
manual.
Faulty solenoid—leaking
Replace solenoid. Refer to
appropriate transmission service
manual.
Low engine power
Correct engine problem. Refer to
engine service manual.
Incorrect fluid level
Correct fluid level. Refer to
appropriate transmission
mechanic’s tips for proper dipstick
calibration.
Extreme fluid temperature
Inspect cooling system and fluid
level
Faulty speed sensor/circuit
Repair circuit or replace speed
sensor(s) (refer to codes P0716,
P0721, or P0726)
Faulty temperature sensor/circuit
Test for temperature reading which
inhibits shifts
Incorrect calibration
Install proper calibration
Faulty shift selector
Replace shift selector
Hydraulic problem
Refer to Range Clutch
Troubleshooting section
Faulty TCM
Replace TCM
ABS fault active
Correct ABS fault
Copyright © 2005 General Motors Corp.
8–5
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
GENERAL TROUBLESHOOTING OF PERFORMANCE COMPLAINTS
Table 8–1. Troubleshooting Performance Complaints (cont’d)
Problem
TRANSMISSION DOES
NOT SHIFT PROPERLY
(ROUGH SHIFTS, SHIFTS
OCCURRING AT TOO LOW
OR TOO HIGH SPEED)
8–6
Probable Cause
Suggested Remedy
Engine idle speed too fast (neutral
to range shift)
Adjust engine idle speed. Refer to
vehicle service manual.
Faulty throttle sensor/circuit
Refer to throttle sensor section for
installation and operation
information (refer to Appendix F)
TCM input voltage low
Test power, ground, charging
system, and battery function
Incorrect shift calibration for
vehicle
Install correct calibration
Instrument panel tachometer
incorrect
Repair or replace tachometer
Incorrectly calibrated electronic
speedometer
Calibrate electronic speedometer
Faulty speed sensor/circuit
Repair circuit or replace speed
sensor (refer to codes P0716,
P0721, or P0726)
Loose speed sensor
Tighten speed sensor retaining
bracket bolt
Incorrect fluid level
Correct fluid level. Refer to
appropriate mechanic’s tips for
proper dipstick calibration.
Crossed wires in harness
Inspect for crossed wires and
correct
Intermittent problems
Inspect wiring harnesses and
connectors (Appendix E)
Loose or damaged speed gear
Replace output bearing nut sensor
retainer
Logic latch valve sticking
Overhaul valve body assembly.
Refer to appropriate transmission
service manual.
Sticking solenoid regulator valve
Overhaul valve body assembly
Refer to appropriate transmission
service manual.
Incorrect calibration
Install correct calibration
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
GENERAL TROUBLESHOOTING OF PERFORMANCE COMPLAINTS
Table 8–1. Troubleshooting Performance Complaints (cont’d)
Problem
Probable Cause
Suggested Remedy
CRUISE CONTROL COMPLAINTS
A. Cruise Control Shift Cycles
Performance shift schedule is being
used
Switch to economy shift schedule
Incorrect droop settings
Modify engine droop settings to
provide a larger speed variation
before reaction occurs (CAT
engines should be set on “soft
cruise”. Cummins engines droop
settings should be +2 mph and
–3 mph.)
RETARDER PERFORMANCE COMPLAINTS
A. Retarder Does Not Apply
Retarder enable input not activated
Turn on retarder enable switch (if
present)
Retarder enable switch not working
Replace retarder enable switch (if
present)
ABS input is active (if vehicle is
equipped with ABS)
None—this is normal. If ABS is
active, retarder will not apply.
Retarder Request below
10.2 percent
Use Allison DOC™ For PC–
Service Tool to determine retarder
request voltage signaled by each
RMR device present. Replace RMR
device, based on test results.
Closed throttle not sensed
Use Allison DOC™ For PC–
Service Tool to check throttle signal.
Throttle must be below 9.8 percent
before retarder will apply. Adjust or
replace TPS.
Exception: If TPS has failed and
Service Brake Status input is sensed
by TCM, the retarder will still be
applied.
Active code inhibiting retarder
Correct cause for setting these
codes: P2685, P2686, P2736,
P2738, P2739, C1312, or C1313
Transmission output speed below
350 rpm (3000 Product Family)
450 rpm (4000 Product Family)
Raise output speed to above
350 rpm (3000 Product Family)
450 rpm (4000 Product Family)
Transmission not in a forward range Shift to a forward range
Copyright © 2005 General Motors Corp.
8–7
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
GENERAL TROUBLESHOOTING OF PERFORMANCE COMPLAINTS
Table 8–1. Troubleshooting Performance Complaints (cont’d)
Problem
Probable Cause
B. Reduced Retarder Effect
Suggested Remedy
Retarder accumulator solenoid not
being energized
Correct cause for setting these
codes: P2685, P2686, P2736,
P2738, P2739, C1312, or C1313
TCM sensing false overheat
condition
Use Allison DOC™ For PC–
Service Tool or VOM to check
retarder temperature sensor.
Replace sensor as required.
Normal response to overheating:
See Table 6–7 in Section 6
(DTC P0218, P2740)
• higher retarder fluid temperature
• higher engine coolant temperature
• higher sump temperature
C. Less Retarder Effect Than
Expected
Transmission fluid aerated due to
incorrect level
Determine transmission fluid level
and correct as required
Wrong retarder control calibration
Measure retarder charging pressure.
Change retarder control calibration,
if necessary.
ABNORMAL ACTIVITIES OR RESPONSES
A. Excessive Creep in First and
Reverse Gears
Engine idle speed too high
Adjust to correct idle speed—
between 500–800 rpm. Refer to
vehicle service manual.
B. No Response to Shift Selector
Shift selector not properly
connected
Test shift selector response with
Allison DOC™ For PC–Service
Tool. If no response, inspect remote
connection and replace if necessary
Using wrong shift selector on dual
station equipment
Use other selector
Faulty shift selector
Replace shift selector
Incorrect fluid level
Correct fluid level. Refer to
appropriate transmission
mechanic’s tips for proper dipstick
calibration.
Main pressure low
Refer to Low Pressure section
Logic latch valves sticking (C1, C3,
or C5 clutch pressure low)
Overhaul valve body assembly.
Refer to appropriate transmission
service manual.
C1 clutch failed or not released
Rebuild C1 clutch assembly. Refer
to appropriate transmission service
manual.
C. Vehicle Moves Forward in
Neutral*
C3 clutch failed or not released
Rebuild C3 clutch assembly. Refer
to appropriate transmission service
manual.
D. Vehicle Moves Backward in
Neutral*
* See explanation of NVL in Section 2–3.
8–8
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
GENERAL TROUBLESHOOTING OF PERFORMANCE COMPLAINTS
Table 8–1. Troubleshooting Performance Complaints (cont’d)
Problem
Probable Cause
D. Vehicle Moves Backward in
Neutral*
C3 clutch failed or not released
EXCESSIVE FLARE —
ENGINE OVERSPEED ON
FULL-THROTTLE UPSHIFTS
TPS Adjustment:
Suggested Remedy
Rebuild C3 clutch assembly. Refer
to appropriate transmission service
manual.
— Overstroke
— Adjust TPS linkage for proper
stroke (Appendix F)
— Loose
— Tighten loose bolts or
connections
Incorrect calibration
Correct calibration
TCM input voltage low
Test electrical system and all
connections from battery and TCM
Incorrect fluid level
Correct fluid level. Refer to
appropriate mechanic’s tips for
proper dipstick calibration
measurements.
Low main pressure
See Low Pressure section
Erratic speed sensor signal
Refer to DTC P0716, P0721, or
P0726
Sticking solenoid regulator valve
(see Solenoid and Clutch sections)
Clean and repair solenoid regulator
valve. Refer to appropriate
transmission service manual.
Piston seals leaking or clutch plates
slipping in range involved (see
Range Clutch Troubleshooting
section)
Overhaul transmission. Refer to
appropriate transmission service
manual.
RANGE CLUTCH TROUBLESHOOTING SECTION
EXCESSIVE SLIPPAGE AND
CLUTCH CHATTER
Incorrect calibration
Verify calibration
TCM input voltage low
Test power, ground, charging
system, and battery functions
Throttle position sensor out of
adjustment or failed
Adjust or replace throttle position
sensor (Appendix F)
Incorrect speed sensor readings
Refer to DTC P0716, P0721, or
P0726
Incorrect fluid level
Correct fluid level. Refer to
appropriate mechanic’s tips for
proper dipstick calibration
measurements.
Main pressure low
Refer to the Low Pressure section
* See Appendix B—Measure main pressure, clutch pressure, and pressure specifications.
Copyright © 2005 General Motors Corp.
8–9
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
GENERAL TROUBLESHOOTING OF PERFORMANCE COMPLAINTS
Table 8–1. Troubleshooting Performance Complaints (cont’d)
Problem
Probable Cause
Suggested Remedy
EXCESSIVE SLIPPAGE AND
CLUTCH CHATTER (cont’d)
Lockup clutch not applied
Inspect lockup clutch system
wiring, pressure, and controls;
repair as necessary. Refer to
appropriate transmission service
manual.*
A. Ranges 1, 2, 3, 4 Only
(6-speed and 3000 7-speed)
Ranges Lo, 1, 2, 3, 4 only
(4000 7-Speed)
C1 clutch slipping, leaks at splitline
gasket, leaks at rotating clutch
seals, leaks at piston seals, C1
clutch plates worn
Inspect control module gasket, C1
clutch plates, and piston and
rotating seals; replace/rebuild as
necessary. Refer to appropriate
transmission service manual.*
B. Ranges 4, 5, 6 Only
(6-speed, 7-speed)
C2 clutch slipping, leaks at splitline
gasket, leaks at rotating clutch
seals, leaks at piston seals, C2
clutch plates worn
Inspect control module gasket, C2
clutch plates, and piston and
rotating seals; replace/rebuild as
necessary. Refer to appropriate
transmission service manual.*
C. Ranges 3, 5, R Only
(6-speed and 4000 7-speed)
Ranges Lo, 3, 5, R only
(3000 7-speed)
C3 clutch slipping, leaks at face
seals, leaks at piston seals, C3
clutch plates worn
Inspect control module face seals,
C3 clutch plates, and piston seals;
replace/rebuild as necessary. Refer
to appropriate transmission service
manual.*
D. Ranges 2, 6 Only
(6-speed and 7-speed)
C4 clutch slipping, leaks at face
seals, leaks at piston seals, C4
clutch plates worn
Inspect control module face seals,
C4 clutch plates, and piston seals;
replace/rebuild as necessary. Refer
to appropriate transmission service
manual.*
E. Ranges 1, R Only
(6-speed and 7-speed)
C5 clutch slipping, leaks at face
seals, leaks at piston seals, C5
clutch plates worn
Inspect control module face seals,
C5 clutch plates, and piston seals;
replace/rebuild as necessary. Refer
to appropriate transmission service
manual.*
F. Range Lo Only
(7-Speed)
C6 clutch slipping, leaks at splitline
gasket(s), leaks at piston seals, C6
clutch plates worn
Inspect control module gasket,
adapter gasket, T-Case gasket(s) C6
clutch plates, and piston seals;
replace/rebuild as necessary. Refer
to appropriate transmission service
manual.*
LOW PRESSURE SECTION
A. Low Main Pressure in
All Ranges
(Including C6, T-Case)
Incorrect fluid level
Correct fluid level. Refer to the
appropriate mechanic’s tips for
correct dipstick calibration.*
Oil filter element clogged or faulty
Replace oil filter. Refer to the
appropriate mechanic’s tips.
* See Appendix B—Measure main pressure, clutch pressure, and pressure specifications.
8–10
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
GENERAL TROUBLESHOOTING OF PERFORMANCE COMPLAINTS
Table 8–1. Troubleshooting Performance Complaints (cont’d)
Problem
A. Low Main Pressure in
All Ranges
(Including C6, T-Case)
(cont’d)
Probable Cause
Plugged or faulty suction filter
Clean or replace oil suction filter
element and refill the transmission.
Refer to the appropriate mechanic’s
tips.
Main pressure regulator valve
sticking
Overhaul control module assembly.
Refer to appropriate transmission
service manual.
Main pressure regulator valve
spring weak, broken, or missing
Test spring and replace if
necessary. Refer to appropriate
transmission service manual.
Control module body leakage
(separator plate not flat, separator
plate gasket leakage, loose control
valve body bolts)
Replace or rebuild control module
assembly. Care should be taken
when removing and labeling shift
springs. Refer to appropriate
transmission service manual.
Faulty or incorrect fluid pressure
gauge
Repair or replace gauge
Oil pump worn or damaged
Replace or rebuild oil pump. Refer
to appropriate transmission service
manual.
B. Clutch Pressure Low in Specific
Ranges, Normal Pressure in
Other Ranges
C. Low Lubrication Pressure
Suggested Remedy
See Range Clutch Troubleshooting
section and Appendix B
Incorrect fluid level
Correct fluid level. Refer to the
appropriate mechanic’s tips for
proper dipstick calibration.
Plugged lube filter
Change filter. Refer to the
appropriate mechanic’s tips.
Excessive internal fluid leakage
Measure other pressures (above
items); also inspect control module
mounting bolts; lubrication valve
and spring. Refer to appropriate
transmission service manual.
Broken or damaged converter
regulator retaining pin
Replace damaged or broken parts.
Refer to appropriate transmission
service manual.
Cooler lines restricted or leaking
Inspect for kinks, leakage; reroute
or replace lines as necessary
Copyright © 2005 General Motors Corp.
8–11
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
GENERAL TROUBLESHOOTING OF PERFORMANCE COMPLAINTS
Table 8–1. Troubleshooting Performance Complaints (cont’d)
Problem
C. Low Lubrication Pressure
(cont’d)
Probable Cause
Suggested Remedy
Lubrication valve sticking
Replace lubrication valve
Cooler plugged
Clean or replace cooler
Faulty gauge
Repair or replace gauge
Not in gear
Select D (Drive)
Low fluid level, aerated fluid
Add fluid to proper level. Refer to
the appropriate mechanic’s tips for
proper dipstick calibration.
Incorrect torque converter
Replace torque converter. Refer to
appropriate transmission service
manual.
Clutch pressure low
Refer to Low Pressure section and
Appendix B
C1 or C5 clutch slipping.
NOTE: Use the Allison DOC™
For PC–Service Tool to check
turbine speed.
Rebuild C1 or C5 clutch. Refer to
appropriate transmission service
manual.
Higher power engine
Confirm proper engine match
Engine not performing efficiently
(may be due to plugged or restricted
injectors, high altitude conditions,
dirty air filters, out of time, throttle
linkage, electronic engine controls
problem)
Refer to vehicle engine
manufacturer’s manual or vehicle
service manual
Stall speeds of 66 percent of normal
implies freewheeling stator
Replace or rebuild converter
assembly. Refer to appropriate
transmission service manual.
Incorrect torque converter
Install correct torque converter.
Refer to appropriate transmission
service manual.
Aerated fluid—incorrect fluid level
Adjust fluid to proper level, check
for defective pump. Refer to the
appropriate mechanic’s tips and
transmission service manual.
Air flow to cooler obstructed
Remove air flow obstruction
Engine overheat
Correct overheat situation. Refer to
vehicle service manual.
STALLS IN FIRST RANGE
A. High Stall Speeds
B. Low Stall Speeds
OVERHEATING IN ALL
RANGES
8–12
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
GENERAL TROUBLESHOOTING OF PERFORMANCE COMPLAINTS
Table 8–1. Troubleshooting Performance Complaints (cont’d)
Problem
OVERHEATING IN ALL
RANGES (cont’d)
Probable Cause
Inaccurate temperature gauge or
sending unit
Suggested Remedy
Replace gauge and/or sending unit
Inaccurate sump temperature sensor Replace temperature sensor or
internal harness. Refer to
appropriate transmission service
manual.
FLUID COMES OUT OF THE
FLUID FILL TUBE AND/OR
BREATHER
Transmission cooler lines reversed
Connect cooler lines properly (oil
and water should flow in opposite
directions)
Fluid cooler lines restricted
Remove restrictions, clean or
replace lines. Refer to vehicle
service manual.
Torque converter (wrong converter,
no lockup, stuck stator, or slipping
stator)
Replace or repair converter
assembly. Refer to appropriate
transmission service manual.
NOTE: Stuck stator will not allow
cool down in neutral.
Cooler flow loss due to internal
leakage
Overhaul transmission. Refer to
appropriate transmission service
manual.
Inadequate cooler sizing
See vehicle OEM for specifications
Excessive cooler circuit pressure
drop
Test for plugged cooler, lines too
small, collapsed hose, too many
elbows in circuit
Dipstick loose
Tighten cap, replace if necessary
Fluid level too high
Drain to proper level. Refer to the
appropriate mechanic’s tips.
Fluid level too low
Add fluid to proper level
Breather stopped up—clogged
Clean or replace breather. Refer to
appropriate transmission service
manual.
Fluid contaminated with foreign
liquid
Drain and replace fluid. Locate and
fix source of additional fluid. Refer
to appropriate transmission service
manual if repair is needed.
Dipstick or fill tube seal worn
Replace seal or dipstick
Incorrect dipstick marking
Calibrate dipstick. Refer to the
appropriate mechanic’s tips.
Copyright © 2005 General Motors Corp.
8–13
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
GENERAL TROUBLESHOOTING OF PERFORMANCE COMPLAINTS
Table 8–1. Troubleshooting Performance Complaints (cont’d)
Problem
NOISE OCCURRING
INTERMITTENTLY (BUZZING)
LEAKING FLUID
(OUTPUT SHAFT)
TRANSMISSION INPUT
8–14
Probable Cause
Suggested Remedy
Low fluid level
Add fluid to proper level. Refer to
the appropriate mechanic’s tips for
proper dipstick calibration.
Air leak in oil suction screen
canister
Replace oil suction screen canister.
Refer to appropriate transmission
service manual.
Clogged filters
Replace filters. Refer to the
appropriate mechanic’s tips.
Aerated fluid causes noisy pump
Correct fluid level. Refer to the
appropriate mechanic’s tips for
proper dipstick calibration.
Low main pressure causes main
regulator valve to oscillate
See Low Pressure section
Faulty or missing seal at output
flange
Install new lip-type seal in rear of
transmission housing. Refer to
appropriate transmission service
manual.
Machine lead on output flange seal
surface
Replace flange
Flange worn at seal surface
Replace flange
Insufficient seal around seal OD
When replacing seal, apply sealant.
Refer to appropriate transmission
service manual.
Damaged, missing, or loose output
flange bolts
Replace and/or torque output flange
bolts
Damaged or missing flange button
O-ring
Replace flange button O-ring
Damaged or missing bolt O-rings
Replace O-rings
Front seal leaks
Replace front seal. Refer to
appropriate transmission service
manual.
Converter leaks
Inspect converter seals, cracked
converter pump tangs, converter
cover, or converter housing
porosity; replace parts as required.
Refer to appropriate transmission
service manual.
PTO driveline out of specification
Bring driveline into specification
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
GENERAL TROUBLESHOOTING OF PERFORMANCE COMPLAINTS
Table 8–1. Troubleshooting Performance Complaints (cont’d)
Problem
DIRTY FLUID
Probable Cause
Suggested Remedy
Failure to change fluid and filters
Change fluid and install new filters.
Refer to the appropriate mechanic’s
tips.
Excessive heat
Refer to Overheating section
Damaged fluid filter/seals
Replace oil filter/seals. Refer to the
appropriate mechanic’s tips.
Substandard fluid
Use recommended fluid. Refer to
the appropriate mechanic’s tips.
Clutch/transmission failure
Overhaul transmission. Refer to
appropriate transmission service
manual.
POWER TAKEOFF (PTO)*
A. Leaks
B. Noisy PTO
C. No or Intermittent Operation
(Clutched Drive)
Damaged or cocked seal
Replace seal
PTO flange grooved at seal
Replace PTO flange
Loose flange
Inspect flange and bolts; replace if
necessary and properly torque bolts
Loose bolts or damaged gaskets
Replace gasket and/or properly
torque bolts
Loose or damaged hydraulic lines
(clutched drive)
Tighten fittings. Replace if
necessary.
Faulty driven component
Replace faulty driven component
Gears or bearings worn, damaged,
or contaminated
Rebuild PTO with new gears or
bearings
Electrical problem (switch,
connectors, solenoid, or wires)
Inspect for electrical problem and
repair (Appendix E)
Damaged or worn clutch
Rebuild clutch assembly
Clutch piston seals damaged or
missing
Rebuild clutch assembly
Inadequate fluid pressure to PTO
Inspect and repair fluid pressure
supply; line kinked, loose, or
plugged; orifice too small
Engine speed outside operating
band
Increase or reduce engine speed to
move within operating band
Drive or driven gear teeth damaged
Replace damaged gears. Refer to
appropriate transmission service
manual.
* Contact your nearest Allison dealer/distributor with specific questions relating to PTO repair.
Copyright © 2005 General Motors Corp.
8–15
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
GENERAL TROUBLESHOOTING OF PERFORMANCE COMPLAINTS
Table 8–1. Troubleshooting Performance Complaints (cont’d)
Problem
Probable Cause
Suggested Remedy
TRANSFER CASE (T-CASE)
A. Will Not Go Into Lo Range
TPS adjustment
Properly adjust TPS (Appendix F)
Engine speed too high
Reduce Engine Speed
Wrong calibration
Calibrate properly
Wrong control module (6 speed
instead of 7 speed)
Install correct control module
Faulty wiring, solenoid connectors
Inspect wiring and connectors in
control module. Refer to
appropriate transmission service
manual.
Faulty C6 seals
Replace C6 assembly piston seals.
Refer to appropriate transmission
service manual.
Worn C6 clutch plates
Rebuild C6. Refer to appropriate
transmission service manual.
B. Makes Excessive Noise
Improperly shimmed bearings
Inspect all T-case bearings as
directed in transmission repair
manual. Reshim as necessary.
C. No Front Output Drive
Differential clutch bad (C7 piston
seals, C7 rotating seals, C7 clutch
plates, C7 check ball)
Rebuild differential clutch. Refer to
appropriate transmission service
manual.
C7 electrical (wires, solenoids,
terminals, connectors)
Inspect and repair C7 electrical
system (Appendix E)
Damaged output seal, output flange
seal journal, gasketed mating
surfaces, bearing endcaps, electrical
connector, oil scavenge line
Determine source of leak and
repair. Refer to appropriate
transmission service manual.
D. Transmission Fluid Leaks
8–16
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
GENERAL TROUBLESHOOTING OF PERFORMANCE COMPLAINTS
Table 8–2. Resistance Module Troubleshooting Data
Resistance Test in
Resistance Module*
Voltage Signal**
Wiring to
Control Device
Terminals
Resistance
Ω ± 5%
KΩ
% Retarder
Application
Voltage
± 0.2V
Device Terminal
Auto Full On
A to C
12
100
3.6
No connections
Pressure Switch
Full On
High
A to C
32
0
100
1.1
3.6
A
B
3-Step E-10R Bendix
Pedal
A to C
32
0
32
58
100
1.1
1.9
2.8
3.6
A
B
C
D
6-Step Hand Lever —
Off
Position 1
Position 2
Position 3
Position 4
Position 5
Position 6
A to C
32
0
16
28
48
65
84
100
1.1
1.5
1.9
2.3
2.8
3.2
3.6
+
1
2
3
4
5
6
Auto 1/2 On
A to C
12
50
2.4
No connections
3 Pressure Switches —
Low
A to C
32
0
32
1.1
1.9
Medium
68
2.3
High
100
3.6
32
1.9
Medium
68
2.8
High
100
3.6
0
100
0.7–1.2
3.4–3.5
Description
Auto 1/3 On
2 Pressure Switches
Auto
Dedicated Pedal
A to C
No Tests
A
B
A
B
A
B
21.4
Interface not a
resistance module
A
B
A
B
A
B
C
* Resistance module must be disconnected from the wiring harness and retarder control devices.
** These voltages must be measured between terminals A and B.
Copyright © 2005 General Motors Corp.
8–17
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
APPENDICES
Appendix A
Identification of Potential Circuit Problems
Appendix B
Measuring Clutch and Retarder Pressures
Appendix C
Solenoid and Clutch Chart
Appendix D
Wire/Connector Chart
Appendix E
Connector Part Numbers, Terminal Part Numbers,
Tool Part Numbers, and Repair Instructions
Appendix F
Throttle Position Sensor Adjustment
Appendix G
Welding on Vehicle/Vehicle Interface Module
Appendix H
Hydraulic Schematics
Appendix J
3000 and 4000 Product Families Wiring Schematic
Appendix K
Solenoid Resistance Charts
Appendix L
Externally-Generated Electronic Interference
Appendix M
Diagnostic Tree—3000 and 4000 Product Families
Hydraulic System
Appendix N
Allison DOC™ For PC–Service Tool
Appendix P
Input/Output Functions
Appendix Q
Thermistor Troubleshooting Information
Appendix R
SAE J1939 Communication Link
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
APPENDIX A—IDENTIFICATION OF POTENTIAL CIRCUIT PROBLEMS
Intermittent codes are a result of faults that are detected, logged, and then disappear, only to recur later. If, when
troubleshooting, a code is cleared in anticipation of it recurring and it does not, check the items in the following list
for the fault’s source.
A.
Circuit Inspection
Intermittent power/ground problems—can cause voltage problems during TCM diagnostic checks
which can set various codes depending upon where the TCM was in the diagnostic process.
• Damaged terminals.
• Dirty or corroded terminals.
• Terminals not fully seated in the connector. Inspect indicated wires by uncoupling connector and
gently pulling on the wire at the rear of the connector and checking for excessive terminal
movement.
• Connectors not fully mated. Inspect for missing or damaged locktabs.
• Screws or other sharp pointed objects pushed into or through one of the harnesses.
• Harnesses which have rubbed through and may be allowing intermittent electrical contact between
two wires or between wires and vehicle frame members.
• Broken wires within the braiding and insulation.
B.
Finding an Intermittent Fault Condition
To find a fault, like one of those listed, examine all connectors and the external wiring harnesses.
Harness routing may make it difficult to see or feel the complete harness. However, it is important to
thoroughly check each harness for chafed or damaged areas. Road vibrations and bumps can damage
a poorly installed harness by moving it against sharp edges and cause some of the faults. If a visual
inspection does not identify a cause, move and wiggle the harness by hand until the fault is
duplicated.
The next most probable cause of an intermittent code is an electronic part exposed to excessive
vibration, heat, or moisture. Examples of this are:
(1) Exposed harness wires subjected to moisture.
(2) A defective connector seal allows moisture to enter the connector or part.
(3) An electronic part (TCM, shift selector, solenoid, or throttle sensor) affected by vibration, heat, or
moisture may cause abnormal electrical conditions within the part.
When troubleshooting Item 3, eliminate all other possible causes before replacing any parts.
Another cause of intermittent codes is good parts in an abnormal environment. The abnormal
environment will usually include excessive heat, moisture, or voltage. For example, an TCM that
receives excessive voltage will generate a diagnostic code as it senses high voltage in a circuit. The
code may not be repeated consistently because different circuits may have this condition on each
check. The last step in finding an intermittent code is to observe if the code is set during sudden
changes in the operating environment.
Troubleshooting an intermittent code requires looking for common conditions that are present
whenever the code is diagnosed.
Copyright © 2005 General Motors Corp.
A–1
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
APPENDIX A—IDENTIFICATION OF POTENTIAL CIRCUIT PROBLEMS
C. Recurring Conditions
A recurring condition might be:
• Rain
• Outside temperature above or below a certain temperature
• Only on right-hand or left-hand turns
• When the vehicle hits a bump, etc.
If such a condition can be related to the code, it is easier to find the cause. If the time between code
occurrences is very short, troubleshooting is easier than if it is several weeks or more between code
occurrences.
A–2
Copyright © 2005 General Motors Corp.
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
APPENDIX B— MEASURING CLUTCH AND RETARDER PRESSURES
Testing individual clutch pressures helps to determine if a transmission malfunction is due to a mechanical or an
electrical problem. Properly making these pressure checks requires transmission and vehicle (or test stand)
preparation, recording of data, and comparing recorded data against specifications provided. These instructions are
for all 3000 and 4000 Product Families transmissions.
NOTE:
Determine if there are diagnostic codes set which are related to the transmission difficulty you are
evaluating. Proceed to make mechanical preparations for measuring clutch pressures after codes have
first been evaluated.
A.
Transmission and Vehicle Preparation
1. Remove the plugs from the pressure tap locations where measurement is desired (Figure B–1).
3000 PRODUCT FAMILY
(EXCEPT 7-SPEED)
3000 PRODUCT FAMILY
7-SPEED TRANSFER CASE
4000 PRODUCT FAMILY
C3
C6 (3000 PRODUCT
FAMILY ONLY)
C5
C3
C5
MAIN
C7
MAIN
LU
C2
LU
C4
T-CASE
CONNECTOR
C1
FRONT VIEW
C6 PRESSURE TAP
(On left side of
adapter housing,
near the bottom)
NOTE: Retarder charging pressure tap is located on the
retarder control valve body for all models with retarder.
MAIN
C2
C4
C1
4000
PRODUCT
FAMILY
7-SPEED
V05929.01.02
Figure B–1. Clutch Pressure Check Points
CAUTION:
Be sure that the hydraulic fittings have the same thread as the plugs
removed (7/16-20 UNF-2A). Also please note that these fittings must be straight
thread, O-ring style. Failure to do this will result in damage to the control
module.
2. Install hydraulic fittings suitable for attaching pressure gauges or transducers.
3. Connect pressure gauges or transducers. Pressure gauge set J 26417-A is available for this
purpose. See Table B–2 for pressure levels expected.
Copyright © 2005 General Motors Corp.
B–1
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
APPENDIX B— MEASURING CLUTCH AND RETARDER PRESSURES
4. Be sure that engine speed can be monitored (Allison DOC For PC–Service Tool may be used for
this purpose).
5. Be sure that transmission sump fluid temperature can be measured (Allison DOC For PC–Service
Tool may be used for this purpose).
6. Be sure that the transmission has enough fluid for cold operation until an operating temperature
fluid level can be set.
7. Bring the transmission to normal operating temperature of 71–93ºC (160–200ºF). Inspect for fluid
leaks in the added pressure gauge/transducer lines. Repair leaks as needed. Be sure that fluid level
is correct.
B.
Recording Data
1. Use the Allison DOC For PC–Service Tool, which allows checking of individual range clutch
pressures, with the vehicle stationary. Consult Appendix N or Allison publication GN3433EN,
User Guide for Allison DOC PC–Service Tool, for Action Request and select Clutch Test
Mode. Follow instructions to test clutch pressures in individual ranges.
NOTE:
Check lockup clutch pressure by driving the vehicle in a range where lockup can be obtained. Record
the pressure values at the engine speed and sump fluid temperature values shown in Table B–1. The
lockup clutch is functioning correctly when engine speed and turbine speed values are equal as
recorded from Allison DOC For PC–Service Tool.
2. Consult Table B–1 and locate the transmission model that you are testing.
3. Operate the transmission at the conditions shown in Table B–1 and record engine speed,
transmission sump fluid temperature, main hydraulic pressure, and clutch pressures in the ranges
where a problem is suspected.
Table B–1. Clutch Pressure Test Conditions
Sump Fluid
Temperature
71–93ºC
(160–200ºF)
Transmission Model/ Test Type
All Models (except 3000 Product
Family)—Idle Test
Engine rpm
580–620
3000 Product Family—Idle Test
580–620
71–93ºC
(160–200ºF)
3000 Product Family (except 7-Speed
Models)—High Speed
2080–2120
71–93ºC
(160–200ºF)
B–2
Copyright © 2005 General Motors Corp.
Range
Neutral
Reverse
1C
2C (2nd range start)
Neutral
Reverse
LowC
1C
Reverse
Neutral
1C
2C
2L
3L
4L
5L
6L
Clutches
Pressurized
C5
C3 C5
C1 C5
C1 C4
C5
C3 C5
C3 C6
C1 C5
C3 C5
C5
C1 C5
C1 C4
C1 C4 LU
C1 C3 LU
C1 C2 LU
C2 C3 LU
C2 C4 LU
3000 AND 4000 PRODUCT FAMILIES TROUBLESHOOTING MANUAL—ALLISON 4th GENERATION CONTROLS
APPENDIX B— MEASURING CLUTCH AND RETARDER PRESSURES
Table B–1. Clutch Pressure Test Conditions (cont’d)
Transmission Model/ Test Type
3000 Product Family 7-Speed
Models—High Speed
Engine rpm
2080–2120
4000 Product Family—High Speed
1780–1820
Sump Fluid
Temperature
71–93ºC
(160–200ºF)
71–93ºC
(160–200ºF)
Range
Reverse
Neutral
LowC
1C
2C
2L
3L
4L
5L
6L
Reverse
Neutral
LowC**
1C
2C
2L
3L
4L
5L
6L
Clutches
Pressurized
C3 C5
C5
C3 C6
C1 C5
C1 C4
C1 C4 LU
C1 C3 LU
C1 C2 LU
C2 C3 LU
C2 C4 LU
C3 C5
C5
C1 C6
C1 C5
C1 C4
C1 C4 LU
C1 C3 LU
C1 C2 LU
C2 C3 LU
C2 C4 LU
** Only applies to HD 4070.
C. Comparing Recorded Data to Specifications
1. Be sure that engine speed and transmission sump fluid temperatures were within the values specified in Table B–1.
2. Compare the main pressure and clutch pressure data, recorded in Step B, with the specifications in
Table B–2.
3. If clutch pressures are within specifications, return the transmission and vehicle to their original
configuration and proceed with electrical troubleshooting.
4. If clutch pressures are not within specification, take corrective action to replace the internal parts
of the transmission necessary to correct the problem. (Refer to the appropriate transmission service
manual for the model being tested.)
5. Review pressure values after the transmission has been repaired.
6. Return the transmission to its original configuration. (Remove instrumentation and reinstall any
components removed for the pressure testing.)
Copyright © 2005 General Motors Corp.
B–3
B–4
3000 Product
Family—Idle
Transmission
Model/Test
Type
580–620
Engine
rpm
1515–2035
(220–295)
1310–1725
(190–250)
1450–2035
(210–295)
1170–1585
(170–230)
1240–1725
(180–250)
870–1340
(125–195)
1240–1725
(180–250)
870–1340
(125–195)
1240–1725
(180–250)
870–1340
(125–195)
Neutral
Main Mod OFF
Neutral
Main Mod ON
Reverse
Main Mod OFF
Reverse
Main Mod ON
Low C (3000 7-Speed)
Main Mod OFF
Low C (3000 7-Speed)
Main Mod ON
1C
Main Mod OFF
1C
Main Mod ON
2C
Main Mod OFF
2C
Main Mod ON
Range
Main Press.
Spec kPa
[psi]
C1, C4
C1, C4
C1, C5
C1, C5
C3, C6
C3, C6
C3, C5
C3, C5
C5
C5
Clutches
Applied
795–1340
(115–195)
1165–1725
(170–250)
795–1340
(115–195)
1165–1725
(170–250)
795–1340
(115–195)
1165–1725
(170–250)
1095–1585
(160–230)
1375–2035
(200–295)
1235–1725
(180–250
1440–2035
(210–295)
Range Clutch
Press. Spec*
kPa [psi]
Table B–2. Main Pressure and Clutch Pressure Specifications
(Sump Fluid Temperature Same as in Table B–1)
10–35
(1–5)
10–35
(1–5)
10–35
(1–5)
10–35
(1–5)
10–35
(1–5)
10–35
(1–5)
10–35
(1–5)
10–35
(1–5)
10–35
(1–5)
10–35
(1–5)
Lube Pressure
Spec*
kPa [psi]
795–1340
(115–195)
1165–1725
(170–250)
795–1340
(115–195)
1165–1725
(170–250)
795–1340
(115–195)
1165–1725
(170–250)
1095–1585
(160–230)
1375–2035
(200–295)
1235–1725
(180–250)
1440–2035
(210–295)
Dropbox Main
Press. Spec*
kPa [psi]
3000/4000 PRODUCT FAMILIES 4TH GENERATION ELECTRONIC CONTROLS TROUBLESHOOTING MANUAL
APPENDIX B—CHECKING CLUTCH AND RETARDER PRESSURES
Copyright © 2005 General Motors Corp.
3000 Product
Family—High Speed
Transmission
Model/Test
Type
1805–2205
(260–320)
1415–1725
(205–250)
1805–2205
(260–320)
1550–1965
(225–285)
1550–1965
(225–285)
1550–1965
(225–285)
1080–1365
(155–200)
1550–1965
(225–285)
1080–1365
(155–200)
1550–1965
(225–285)
1080–1365
(155–200)
1550–1965
(225–285)
1080–1365
(155–200)
1345-1590
(220–290)
1035–1415
(150–205)
Neutral
Main Mod ON
Reverse
Low C (3000 7-Speed)
1C
2C
2L
3C
3L
4C
4L
5C
5L
6C
6L
Range
Main Press.
Spec kPa
[psi]
2080–2120 Neutral
Main Mod OFF
Engine
rpm
Copyright © 2005 General Motors Corp.
C2, C4, LU
C2, C4
C2, C3, LU
C2, C3
C1, C4, LU
C1, C2
C1, C3, LU
C1, C3
C1, C4, LU
C1, C4
C1, C5
C3, C6
C3, C5
C5
C5
Clutches
Applied
960–1415
(140–205)
1270-1590
(185-230)
1005–1365
(145–200)
1475–1965
(215–285)
1005–1365
(145–200)
1475–1965
(215–285)
1005–1365
(145–200)
1475–1965
(215–285)
1005–1365
(145–200)
1475–1965
(215–285)
1475–1965
(215–285)
1475–1965
(215–285)
1730–2205
(250–320)
1335–1725
(195–250)
1730–2205
(250–320)
Range Clutch
Press. Spec*
kPa [psi]
Table B–2. Main Pressure and Clutch Pressure Specifications
(Sump Fluid Temperature Same as in Table B–1) (cont’d)
125–200
(18–30)
125–200
(18–30)
125–200
(18–30)
125–200
(18–30)
125–200
(18–30)
125–200
(18–30)
160–240
(23–35)
160–240
(23–35)
160–240
(23–35)
160–240
(23–35)
160–240
(23–35)
160–240
(23–35)
160–240
(23–35)
160–240
(23–35)
160–240
(23–35)
Lube Pressure
Spec*
kPa [psi]
960–1415
(140–205)
1270-1590
(185-230)
1005–1365
(145–200)
1475–1965
(215–285)
1005–1365
(145–200)
1475–1965
(215–285)
1005–1365
(145–200)
1475–1965
(215–285)
1005–1365
(145–200)
1475–1965
(215–285)
1475–1965
(215–285)
1475–1965
(215–285)
1730–2205
(250–320)
1335–1725
(195–250)
1730–2205
(250–320)
Dropbox Main
Press. Spec*
kPa [psi]
3000/4000 PRODUCT FAMILIES 4TH GENERATION ELECTRONIC CONTROLS TROUBLESHOOTING MANUAL
APPENDIX B—CHECKING CLUTCH AND RETARDER PRESSURES
B–5
B–6
4000 Product
Family—Idle
Transmission
Model/Test
Type
580–620
Engine
rpm
1515–2055
(220–300)
1310–1725
(190–250)
1450–2055
(210–300)
1170–1585
(170–230)
1240–1725
(180–250)
870–1340
(125–195)
1240–1725
(180–250)
870–1340
(125–195)
1240–1725
(180–250)
870–1340
(125–195)
Neutral
Main Mod OFF
Neutral
Main Mod ON
Reverse
Main Mod OFF
Reverse
Main Mod ON
Low C (4000 7-Speed)
Main Mod OFF
Low C (4000 7-Speed)
Main Mod ON
1C
Main Mod OFF
1C
Main Mod ON
2C
Main Mod OFF
2C
Main Mod ON
Range
Main Press.
Spec kPa
[psi]
C1,C4
C1, C4
C1, C5
C1, C5
C1, C6
C1, C6
C3, C5
C3, C5
C5
C5
Clutches
Applied
795–1340
(115–195)
1165–1725
(170–250)
795–1340
(115–195)
1165–1725
(170–250)
795–1340
(115–195)
1165–1725
(170–250)
1095–1585
(160–230)
1375–2055
(200–3