3100A CANOBD2 Code Reader (E).qxd

3100A CANOBD2 Code Reader (E).qxd
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Table of Contents
Title
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Page No.
INTRODUCTION
What is OBD? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1
YOU CAN DO IT! . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2
SAFETY PRECAUTIONS
Safety First! . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3
ABOUT THE CODE READER
Vehicles Covered . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Battery Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Adjustments/Settings and DTC Library . . . . . . . . . . . . . . . . . . .
5
6
6
CODE READER CONTROLS
Controls and Indicators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Display Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10
12
PREPARATION FOR TESTING
Preliminary Vehicle Diagnosis Worksheet . . . . . . . . . . . . . . . .
Before You Begin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14
17
USING THE CODE READER
Code Retrieval Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Erasing Diagnostic Trouble Codes (DTCs) . . . . . . . . . . . . . . . .
I/M Readiness Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
19
25
27
ONBOARD DIAGNOSTICS
Computer Engine Controls . . . . . . . . . . . . . . . . . . . . . . . . . . .
Diagnostic Trouble Codes (DTCs) . . . . . . . . . . . . . . . . . . . . . .
OBD 2 Monitors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
33
39
42
GLOSSARY
Glossary of Terms and Abbreviations
...................
49
WARRANTY AND SERVICING
Limited One Year Warranty . . . . . . . . . . . . . . . . . . . . . . . . . . .
Service Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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OBD2
Introduction
WHAT IS OBD?
WHAT IS OBD?
The OBD2 Code Reader is designed to work on all OBD 2 compliant vehicles. All 1996 and newer vehicles (cars, light trucks
and SUVs) sold in the United States are OBD 2 compliant.
One of the most exciting improvements
in the automobile industry was the addition
of on-board diagnostics (OBD) on vehicles,
or in more basic terms, the computer that
activates the vehicle’s “CHECK ENGINE”
light. OBD 1 was designed to monitor manufacturer-specific systems on vehicles built
from 1981 to 1995. Then came the development of OBD 2, which is on all 1996 cars and light trucks sold in the
U.S. Like its predecessor, OBD 2 was adopted as part of a government
mandate to lower vehicle emissions. But what makes OBD 2 unique is
its universal application for all late model cars and trucks - domestic
and import. This sophisticated program in the vehicle’s main computer
system is designed to detect failures in a range of systems, and can
be accessed through a universal OBD 2 port, which is usually found
under the dashboard. For all OBD systems, if a problem is found, the
computer turns on the “CHECK ENGINE” light to warn the driver, and
sets a Diagnostic Trouble Code (DTC) to identify where the problem
occurred. A special diagnostic tool, such as the OBD2 Code Reader,
is required to retrieve these codes, which consumers and professionals use as a starting point for repairs.
To learn more about vehicle Computer Control Systems and
OBD 2, see COMPUTER ENGINE CONTROLS on page 33.
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1
You Can Do It!
EASY TO USE - EASY TO VIEW - EASY TO DEFINE
Easy To Use . . . .
■
Connect the Code Reader to the
vehicle’s test connector.
■
Turn the ignition key "On.”
■
DO NOT start the engine.
■
Code Reader turns “On” and links automatically.
Easy To View . . . .
■
The Code Reader retrieves stored
codes, Freeze Frame Data and I/M
Readiness status.
■
Codes, I/M Readiness status and
Freeze Frame data are displayed on the
Code Reader’s LCD display. System
status is indicated by LED indicators.
Easy To Define . . . .
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■
Read code definitions from the Code
Reader’s LCD display.
■
View Freeze Frame data.
OBD2
Safety Precautions
SAFETY FIRST!
SAFETY FIRST!
To avoid personal injury, instrument damage and/or
damage to your vehicle; do not use the OBD2 Code Reader
before reading this manual.
This manual describes common test procedures used by
experienced service technicians. Many test procedures
require precautions to avoid accidents that can result in
personal injury, and/or damage to your vehicle or test
equipment. Always read your vehicle's service manual and
follow its safety precautions before and during any test or
service procedure. ALWAYS observe the following general
safety precautions:
When an engine is running, it produces carbon monoxide, a toxic and poisonous gas. To prevent serious injury
or death from carbon monoxide poisoning, operate the
vehicle ONLY in a well-ventilated area.
To protect your eyes from propelled objects as well as
hot or caustic liquids, always wear approved safety
eye protection.
When an engine is running, many parts (such as the
coolant fan, pulleys, fan belt etc.) turn at high speed. To
avoid serious injury, always be aware of moving parts.
Keep a safe distance from these parts as well as other
potentially moving objects.
Engine parts become very hot when the engine is running. To prevent severe burns, avoid contact with hot
engine parts.
P RND L
Before starting an engine for testing or trouble-shooting, make sure the parking brake is engaged. Put the
transmission in park (for automatic transmission) or
neutral (for manual transmission). Block the drive
wheels with suitable blocks.
Connecting or disconnecting test equipment when the
ignition is ON can damage test equipment and the vehicle's electronic components. Turn the ignition OFF
before connecting the Code Reader to or disconnecting
the Code Reader from the vehicle’s Data Link
Connector (DLC).
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Safety Precautions
SAFETY FIRST!
To prevent damage to the on-board computer when taking vehicle electrical measurements, always use a digital multimeter with at least 10 megOhms of impedance.
Fuel and battery vapors are highly flammable. To prevent an explosion, keep all sparks, heated items and
open flames away from the battery and fuel / fuel
vapors. DO NOT SMOKE NEAR THE VEHICLE DURING TESTING.
Don't wear loose clothing or jewelry when working on an
engine. Loose clothing can become caught in the fan,
pulleys, belts, etc. Jewelry is highly conductive, and can
cause a severe burn if it makes contact between a
power source and ground.
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OBD2
About the Code Reader
VEHICLES COVERED
VEHICLES COVERED
The OBD2 Code Reader is designed to work on all OBD 2 compliant
vehicles. All 1996 and newer vehicles (cars and light trucks) sold in the
United States are OBD 2 compliant.
Federal law requires that all 1996 and newer cars and light
trucks sold in the United States must be OBD 2 compliant;
this includes all Domestic, Asian and European vehicles.
Some 1994 and 1995 vehicles are OBD 2 compliant. To find out if a
1994 or 1995 vehicle is OBD 2 compliant, check the following:
1. The Vehicle Emissions Control Information (VECI) Label. This
label is located under the hood or by the radiator of most vehicles. If
the vehicle is OBD 2 compliant, the label will state “OBD II Certified.”
VEHICLE EMISSION CONTROL INFORMATION
ENGINE FAMILY
DISPLACEMENT
VEHICLE
MANUFACTURER
EFN2.6YBT2BA
2.6L
OBD II
CERTIFIED
THIS VEHICLE CONFORMS TO U.S. EPA AND STATE
OF CALIFORNIA REGULATIONS APPLICABLE TO
1999 MODEL YEAR NEW TLEV PASSENGER CARS.
REFER TO SERVICE MANUAL FOR ADDITIONAL INFORMATION
TUNE-UP CONDITIONS: NORMAL OPERATING ENGINE TEMPERATURE,
ACCESSORIES OFF, COOLING FAN OFF, TRANSMISSION IN NEUTRAL
EXHAUST EMISSIONS STANDARDS
CERTIFICATION
IN-USE
SPARK PLUG
TYPE NGK BPRE-11
GAP: 1.1MM
OBD II
CERTIFIED
STANDARD CATEGORY
TLEV
TLEV INTERMEDIATE
CATALYST
2. Government Regulations require that
all OBD 2 compliant vehicles must
have a “common” sixteen-pin Data
Link Connector (DLC).
1 2 3 4 5 6 7 8
9 10111213141516
Some 1994 and 1995 vehicles have 16-pin connectors but
are not OBD 2 compliant. Only those vehicles with a Vehicle
Emissions Control Label stating “OBD II Certified” are OBD 2
compliant.
Data Link Connector (DLC) Location
The 16-pin DLC is usually
located under the instrument
panel (dash), within 12 inches
(300 mm) of center of the
panel, on the driver’s side of
most vehicles. It should be easily accessible and visible from
a kneeling position outside the
vehicle with the door open.
OBD2
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LEFT CORNER
OF DASH
NEAR
CENTER
OF DASH
BEHIND
ASHTRAY
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About the Code Reader
BATTERY REPLACEMENT / ADJUSTMENTS/SETTINGS AND DTC LIBRARY
On some Asian and European vehicles the DLC is located
behind the “ashtray” (the ashtray must be removed to access
it) or on the far left corner of the dash. If the DLC cannot be
located, consult the vehicle’s service manual for the location.
BATTERY REPLACEMENT
Replace batteries when the battery symbol
is visible on display
and/or the 3 LEDS are all lit and no other data is visible on screen.
1. Locate the battery cover on the back of the Code Reader.
2. Slide the battery cover off (use your fingers).
3. Replace batteries with two AA-size batteries (for longer life, use
Alkaline-type batteries).
4. Reinstall the battery cover on the back of the Code Reader.
ADJUSTMENTS/SETTINGS AND DTC LIBRARY
The OBD2 Code Reader lets you make several adjustments and settings to configure the Code Reader to your particular needs. The following functions, adjustments and settings can be performed when the
OBD2 Code Reader is in “MENU Mode”:
■
Adjust Brightness: Adjusts the brightness of the LCD display
screen.
■
DTC Library: Lets you search the library of OBD2 DTC definitions.
■
Select Language: Sets the display language for the Code Reader
to English, French or Spanish.
■
Unit of Measure: Sets the Unit of Measure for the Tool’s display to
USA or metric.
Adjustments and settings can be made only when the Code
Reader is NOT connected to a vehicle.
To enter the MENU Mode:
1. With the Code Reader “off”, press and
hold the SCROLL
button, then
press and release the POWER/LINK
button.
■
The adjustments and setting MENU
displays.
2. Release the SCROLL
button.
DO NOT release the SCROLL
button until the adjustments and settings MENU is visible on the display.
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OBD2
About the Code Reader
ADJUSTMENTS/SETTINGS AND DTC LIBRARY
3. Make adjustments and settings as described in the following paragraphs.
Adjusting Display Brightness
1. Use the SCROLL
button, as necessary, to highlight Adjust Brightness in
the MENU, then press the ENTER/FF
button.
When the last option in the MENU
is reached, pressing the SCROLL
button again will return to the
first menu option.
■
The Adjust Brightness screen displays.
■
The Brightness field shows the current brightness setting, from 0 to 43.
2. Press the SCROLL
button to increase the brightness of the
LCD display (make the display lighter). When the display reaches
button again will
the brightest setting, pressing the SCROLL
return the display to its darkest setting.
3. When the desired brightness is obtained, press the ENTER/FF
button to save your changes and return to the MENU.
Searching for a DTC Definition Using the DTC Library
1. Use the SCROLL
button, as necessary, to highlight DTC Library in the
MENU, then press the ENTER/FF
button.
■ The Enter DTC screen displays. The
screen shows the code “P0000”, with
the “P” highlighted.
2. Use the SCROLL
button, as necessary, to scroll to the desired DTC type
(P=Powertrain, U=Network, B=Body,
C=Chassis), then press the DTC
SCROLL
button.
■ The next character will highlight.
3. Select the remaining characters in the DTC in the same way, pressing the DTC SCROLL
button to confirm each character.
When you have selected all the DTC characters, press the
ENTER/FF
button to view the DTC definition.
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About the Code Reader
ADJUSTMENTS/SETTINGS AND DTC LIBRARY
■
If you entered a “Generic” DTC
(DTCs that start with “P0”, “P2” and
some “P3”):
- The selected DTC and DTC definition (if available), show on the
Code Reader’s LCD display.
■
If you entered a “ManufacturerSpecific” DTC (DTCs that start with
“P1” and some “P3”):
- The “Select Manufacturer” screen
displays.
- Use the SCROLL
button, as
necessary, to highlight the appropriate manufacturer, then
press the ENTER/FF
your vehicle.
button to display the correct DTC for
If a definition for the DTC you
entered is not available, an advisory message shows on the
Code Reader’s LCD display.
4. If you wish to view definitions for additional DTCs, press the ENTER/FF
button to return to the Enter
DTC screen, and repeat steps 2 and 3.
5. When all desired DTCs have been viewed, press the ERASE
button to exit the DTC Library.
Selecting the Display Language
1. Use the SCROLL
button, as necessary, to highlight Select Language in
the MENU, then press the ENTER/FF
button.
When the last option in the MENU
is reached, pressing the SCROLL
button again will return to the
first menu option.
■
The Select Language screen displays.
■
The currently selected
Language is highlighted.
display
2. Press the SCROLL
button, as necessary, to highlight the desired display
language. Pressing the SCROLL
button repeatedly will toggle between
the available selections.
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OBD2
About the Code Reader
ADJUSTMENTS/SETTINGS AND DTC LIBRARY
3. When the desired display language is highlighted, press the
ENTER/FF
button to save your changes and return to the MENU.
Setting the Unit of Measure
1. Use the UP
and DOWN
buttons, as necessary, to highlight Unit of
Measure in the MENU, then press the
ENTER/FF
button.
2. Press the UP
or DOWN
button,
as necessary, to highlight the desired
Unit of Measure.
3. When the desired Unit of Measure
value is selected, press the ENTER/FF
button to save your changes.
Exiting the MENU Mode
1. Use the SCROLL
button, as necessary, to highlight Menu Exit
in the MENU, then press the ENTER/FF
button.
■
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The LCD display returns to the DTC screen.
9
Code Reader Controls
CONTROLS AND INDICATORS
CONTROLS AND INDICATORS
10
6
9
7
8
1
5
2
3
4
Figure 1. Controls and Indicators
See Figure 1 for the locations of items 1 through 10, below.
1.
ERASE button - Erases Diagnostic Trouble Codes (DTCs)
and “Freeze Frame” data from your vehicle’s computer, and resets
Monitor status.
2.
DTC SCROLL button - Displays the DTC View screen and/or
scrolls the LCD display to view DTCs when more than one DTC is
present.
3.
POWER/LINK button - When the Code Reader IS NOT
connected to a vehicle, turns the Code Reader “On” and “Off”. When
the Code Reader is connected to a vehicle, re-links the Code Reader
to the vehicle’s PCM if the Code Reader is taken out of link.
To turn the Code Reader "On", you must press and hold the
POWER/LINK
button for approximately 3 seconds.
4.
ENTER/FF button - When in MENU mode, confirms the
selected option or value. When retrieving DTCs, displays Freeze
Frame data for the highest priority code.
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OBD2
Code Reader Controls
CONTROLS AND INDICATORS
5.
SCROLL button - When in MENU mode, scrolls DOWN
through the menu and submenu selection options. When retrieving and
viewing DTCs, scrolls down through the current display screen to display any additional data. When the end of the screen is reached,
pressing the button again returns to the top of the screen.
6. GREEN LED - Indicates that all engine systems are running normally (all Monitors on the vehicle are active and performing their diagnostic testing, and no DTCs are present).
7. YELLOW LED - Indicates there is a possible problem. A “Pending”
DTC is present and/or some of the vehicle’s emission monitors have
not run their diagnostic testing.
8. RED LED - Indicates there is a problem in one or more of the vehicle’s systems. The red LED is also used to show that DTC(s) are present. DTCs are shown on the Code Reader’s LCD display. In this case,
the Multifunction Indicator (“Check Engine”) lamp on the vehicle’s
instrument panel will light steady on.
9. LCD Display - Displays settings Menu and submenus, test
results, Code Reader functions and Monitor status information. See
DISPLAY FUNCTIONS, on next page, for more details.
10. CABLE - Connects the Code Reader to the vehicle’s Data Link
Connector (DLC).
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Code Reader Controls
DISPLAY FUNCTIONS
DISPLAY FUNCTIONS
2
1
12 10
11
13
3
4
5
6
15
16
7
14
8
9
Figure 2. Display Functions
See Figure 2 for the locations of items 1 through 16, below.
1. I/M MONITOR STATUS field - Identifies the I/M Monitor status area.
2. Monitor icons - Indicate which Monitors are supported by the vehicle under test, and whether or not the associated Monitor has run
its diagnostic testing (Monitor status). When a Monitor icon is solid,
it indicates that the associated Monitor has completed its diagnostic testing. When a Monitor icon is flashing, it indicates that the vehicle supports the associated Monitor, but the Monitor has not yet run
its diagnostic testing.
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3.
Vehicle icon - Indicates whether or not the Code Reader is
being properly powered through the vehicle’s Data Link Connector
(DLC). A visible icon indicates that the Code Reader is being powered through the vehicle’s DLC connector.
4.
Link icon - Indicates whether or not the Code Reader is communicating (linked) with the vehicle’s on-board computer. When visible, the Code Reader is communicating with the computer. If the
Link icon is not visible, the Code Reader is not communicating with
the computer.
5.
Computer icon - When this icon is visible it indicates that the
Code Reader is linked to a personal computer. An optional “Tek
Link Kit” is available that makes it possible to upload retrieved data
to a personal computer.
6.
Code Reader Internal Battery icon - When visible, indicates
the Code Reader batteries are “low” and should be replaced. If the
batteries are not replaced when the battery symbol
is "on", all 3
LEDs will flash for 10 seconds each time the unit is turned “on” as
a last resort indicator to warn you that the batteries need replacement.
OBD2
Code Reader Controls
DISPLAY FUNCTIONS
7. DTC Display Area - Displays the Diagnostic Trouble Code (DTC)
number. Each fault is assigned a code number that is specific to
that fault.
8. Test Data Display Area - Displays DTC definitions and other pertinent test information messages.
9. FREEZE FRAME icon - Indicates that there is Freeze Frame data
from “Priority Code” (Code #1) stored in the vehicle’s computer
memory.
10. MIL icon - Indicates the status of the Malfunction Indicator Lamp
(MIL). The MIL icon is visible only when a DTC has commanded
the MIL on the vehicle’s dashboard to light.
11. PENDING icon - Indicates the currently displayed DTC is a
“Pending” code.
12. HISTORY icon - Indicates the currently displayed DTC is a
“History” code.
13. Code Number Sequence - The Code Reader assigns a
sequence number to each DTC that is present in the computer’s
memory, starting with “01.” This number indicates which code is
currently displayed. Code number “01” is always the highest priority code, and the one for which “Freeze Frame” data has been
stored.
If “01” is a “Pending” code, there may or may not be
“Freeze Frame” data stored in memory.
14. Code Enumerator - Indicates the total number of codes retrieved
from the vehicle’s computer.
15.
Generic DTC icon - When visible, indicates that the currently
displayed DTC is a “generic” or universal code.
16.
Manufacturer Specific DTC icon - When visible, indicates that
the currently displayed DTC is a Manufacturer Specific Code.
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Preparation for Testing
PRELIMINARY VEHICLE DIAGNOSIS WORKSHEET
PRELIMINARY VEHICLE DIAGNOSIS WORKSHEET
The purpose of this form is to help you gather preliminary information on
your vehicle before you retrieve codes. By having a complete account of
your vehicle's current problem(s), you will be able to systematically pinpoint the problem(s) by comparing your answers to the fault codes you
retrieve. You can also provide this information to your mechanic to assist
in diagnosis and help avoid costly and unnecessary repairs. It is important for you to complete this form to help you and/or your mechanic have
a clear understanding of your vehicle's problems. An electronic version
of this Preliminary Vehicle Diagnosis Worksheet is available online at
www.canOBD2.com. You can complete the form online and print a copy
to take to your mechanic.
NAME:
DATE:
VIN*:
YEAR:
MAKE:
MODEL:
ENGINE SIZE:
VEHICLE MILEAGE:
*VIN: Vehicle Identification Number, found at the base of the windshield
on a metallic plate, or at the driver door latch area (consult your vehicle
owner's manual for location).
TRANSMISSION:
❑ Automatic
❑ Manual
Please check all applicable items in each category.
DESCRIBE THE PROBLEM:
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OBD2
Preparation for Testing
PRELIMINARY VEHICLE DIAGNOSIS WORKSHEET
WHEN DID YOU FIRST NOTICE THE PROBLEM:
❑
❑
❑
❑
Just Started
Started Last Week
Started Last Month
Other:
LIST ANY REPAIRS DONE IN THE PAST SIX MONTHS:
PROBLEMS STARTING
❑ No symptoms
❑ Will not crank
❑ Cranks, but will not start
❑ Starts, but takes a long time
ENGINE QUITS OR STALLS
❑ No symptoms
❑ Right after starting
❑ When shifting into gear
❑ During steady-speed driving
❑
❑
❑
❑
IDLING CONDITIONS
❑ No symptoms
❑ Is too slow at all times
❑ Is too fast
❑ Is sometimes too fast or too slow
❑ Is rough or uneven
❑ Fluctuates up and down
RUNNING CONDITIONS
❑ No symptoms
❑ Runs rough
❑ Lacks power
❑ Bucks and jerks
❑ Poor fuel economy
❑ Hesitates or stumbles on
❑
❑
❑
❑
❑
Right after vehicle comes to a stop
While idling
During acceleration
When parking
Backfires
Misfires or cuts out
Engine knocks, pings or rattles
Surges
Dieseling or run-on
accelerations
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Preparation for Testing
PRELIMINARY VEHICLE DIAGNOSIS WORKSHEET
AUTOMATIC TRANSMISSION PROBLEMS (if applicable)
❑ No symptoms
❑ Vehicle does not move when in
gear
❑ Shifts too early or too late
❑ Jerks or bucks
❑ Changes gear incorrectly
PROBLEM OCCURS
❑ Morning
❑ Afternoon
❑ Anytime
ENGINE TEMPERATURE WHEN PROBLEM OCCURS
❑ Cold
❑ Warm
❑ Hot
DRIVING CONDITIONS WHEN PROBLEM OCCURS
❑ Short - less than 2 miles
❑ With headlights on
❑ 2 - 10 miles
❑ During acceleration
❑ Long - more than 10 miles
❑ Mostly driving downhill
❑ Stop and go
❑ Mostly driving uphill
❑ While turning
❑ Mostly driving level
❑ While braking
❑ Mostly driving curvy roads
❑ At gear engagement
❑ Mostly driving rough roads
❑ With A/C operating
DRIVING HABITS
❑ Mostly city driving
❑ Highway
❑ Park vehicle inside
❑ Park vehicle outside
GASOLINE USED
❑ 87 Octane
❑ 89 Octane
❑ Drive less than 10 miles per day
❑ Drive 10 to 50 miles per day
❑ Drive more than 50 miles per day
❑ 91 Octane
❑ More than 91 Octane
WEATHER CONDITIONS WHEN PROBLEM OCCURS
❑ 32 - 55° F (0 - 13° C)
❑ Above 55° F (13° C)
❑ Below freezing (32° F / 0° C)
CHECK ENGINE LIGHT / DASH WARNING LIGHT
❑ Sometimes ON
❑ Never ON
PECULIAR SMELLS
❑ "Hot"
❑ Sulfur ("rotten egg")
❑ Burning rubber
❑ Gasoline
❑ Burning oil
❑ Electrical
STRANGE NOISES
❑ Rattle
❑ Knock
❑ Squeak
❑ Other
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❑ Always ON
OBD2
Preparation for Testing
BEFORE YOU BEGIN
BEFORE YOU BEGIN
The OBD2 Code Reader aids
in monitoring electronic- and
emissions-related faults in
your vehicle and retrieving
fault codes related to malfunctions in these systems.
Mechanical problems such as
low oil level or damaged
hoses, wiring or electrical connectors can cause poor engine performance and may also cause a fault code to set. Fix any known mechanical problems before performing any test. See your vehicle’s service
manual or a mechanic for more information.
Check the following areas before starting any test:
E
■
Check the engine oil, power steering fluid, transmission fluid (if
applicable), engine coolant and other fluids for proper levels. Top off
low fluid levels if needed.
■
Make sure the air filter is clean and in good condition. Make sure all
air filter ducts are properly connected. Check the air filter ducts for
holes, rips or cracks.
■
Make sure all engine belts are in good condition. Check for cracked,
torn, brittle, loose or missing belts.
■
Make sure mechanical linkages to engine sensors (throttle,
gearshift position, transmission, etc.) are secure and properly connected. See your vehicle’s service manual for locations.
■
Check all rubber hoses (radiator) and steel hoses (vacuum/fuel) for
leaks, cracks, blockage or other damage. Make sure all hoses are
routed and connected properly.
■
Make sure all spark plugs are clean and in good condition. Check
for damaged, loose, disconnected or missing spark plug wires.
■
Make sure the battery terminals are clean and tight. Check for corrosion or broken connections. Check for proper battery and charging system voltages.
■
Check all electrical wiring and harnesses for proper connection.
Make sure wire insulation is in good condition, and there are no
bare wires.
■
Make sure the engine is mechanically sound. If needed, perform a
compression check, engine vacuum check, timing check (if applicable), etc.
OBD2
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Preparation for Testing
VEHICLE SERVICE MANUALS
VEHICLE SERVICE MANUALS
Always refer to the manufacturer’s service manual for your vehicle
before performing any test or repair procedures. Contact your local car
dealership, auto parts store or bookstore for availability of these manuals. The following companies publish valuable repair manuals:
■
Haynes Publications
861 Lawrence Drive
Newbury Park, California 91320
Phone: 800-442-9637
■
Mitchell International
14145 Danielson Street
Poway, California 92064
Phone: 888-724-6742
■
Motor Publications
5600 Crooks Road, Suite 200
Troy, Michigan 48098
Phone: 800-426-6867
FACTORY SOURCES
Ford, GM, Chrysler, Honda, Isuzu, Hyundai and Subaru Service
Manuals
■
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Helm Inc.
14310 Hamilton Avenue
Highland Park, Michigan 48203
Phone: 800-782-4356
OBD2
Using the Code Reader
CODE RETRIEVAL PROCEDURE
CODE RETRIEVAL PROCEDURE
Retrieving and using Diagnostic Trouble Codes (DTCs) for
troubleshooting vehicle operation is only one part of an
overall diagnostic strategy.
Never replace a part based only on the DTC definition.
Each DTC has a set of testing procedures, instructions
and flow charts that must be followed to confirm the location of the problem. This information is found in the vehicle's
service manual. Always refer to the vehicle's service manual
for detailed testing instructions.
Check your vehicle thoroughly before performing
any test. See Before You Begin on page 17 for
details.
ALWAYS observe safety precautions whenever working on a
vehicle. See Safety Precautions on page 3 for more information.
1. Turn the ignition off.
2. Locate the vehicle's 16-pin Data Link
Connector (DLC). See page 5 for connector location.
Some DLCs have a plastic cover
that must be removed before connecting the Code Reader cable
connector.
If the Code Reader is ON, turn it
OFF by pressing the POWER/LINK
button BEFORE connecting
the Code Reader to the DLC.
3. Connect the Code Reader cable connector to the vehicle’s DLC.
The cable connector is keyed and will only fit one way.
■
If you have problems connecting the cable connector to the DLC,
rotate the connector 180° and try again.
■
If you still have problems, check the DLC on the vehicle and on
the Code Reader. Refer to your vehicle’s service manual to properly check the vehicle’s DLC.
4. When the Code Reader’s cable connector is properly connected to
the vehicle’s DLC, the unit automatically turns ON, and LINKS to
the vehicle’s on-board computer.
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19
Using the Code Reader
CODE RETRIEVAL PROCEDURE
■
If the unit does not power on automatically when connected to
the vehicle’s DLC connector, it usually indicates there is no
power present at the vehicle’s DLC connector. Check your fuse
panel and replace any burned-out fuses.
■
If replacing the fuse(s) does not correct the problem, consult your
vehicle’s repair manual to identify the proper computer (PCM) fuse/
circuit, and perform any necessary repairs before proceeding.
5. Turn the ignition on. DO NOT start the engine.
■
The Code Reader will automatically
start a check of the vehicle’s computer to determine which type of communication protocol it is using. When
the Code Reader identifies the computer’s communication protocol, a
communication link is established.
The protocol type used by the vehicle’s computer is shown on the LCD display.
A PROTOCOL is a set of rules and procedures for regulating data transmission between computers, and between
testing equipment and computers. As of this writing, five
different types of protocols (ISO 9141, Keyword 2000,
J1850 PWM, J1850 VPW and CAN) are in use by vehicle
manufacturers. The Code Reader automatically identifies
the protocol type and establishes a communication link
with the vehicle’s computer.
6. After approximately 10~60 seconds, the Code Reader will retrieve
and display any Diagnostic Trouble Code and Monitor Status
retrieved from the vehicle’s computer memory.
■
If the Code Reader fails to link to the vehicle’s computer a “Linking
Failed” message shows on the Code
Reader’s LCD display.
- Verify the connection at the DLC
and verify the ignition is ON.
- Turn the ignition OFF, wait 5 seconds, then turn back ON to reset
the computer.
- Ensure your vehicle is OBD2 compliant. See Vehicles
Covered on page 5 for vehicle compliance verification information.
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OBD2
Using the Code Reader
CODE RETRIEVAL PROCEDURE
■
The Code Reader will automatically
re-link to the vehicle’s computer every
30 seconds to refresh the data being
retrieved. When data is being refreshed, the message “One moment
Auto – link in progress” is shown on the
LCD display. This action repeats as
long as the Code Reader is communicating with the vehicle’s computer.
■
The Code Reader will display a code
only if codes are present in the vehicle’s computer memory. If no codes
are present, a “No DTC’s are presently stored in the vehicle’s computer” is
displayed.
■
The Code Reader is capable of retrieving and storing up to 32
codes in memory, for immediate or later viewing.
7. To read the display:
Refer to Display Functions on page 12 for a description
of LCD display elements.
OBD2
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■
A visible
icon indicates that the Code Reader is being powered through the vehicle’s DLC connector.
■
A visible
icon indicates that the Code Reader is linked to
(communicating with) the vehicle’s computer.
■
The I/M Monitor Status icons indicate the type and number of
Monitors the vehicle supports, and provides indications of the
current status of the vehicle’s Monitors. A solid Monitor icon indicates the associated Monitor has run and completed its testing.
A blinking Monitor icon indicates the associated Monitor has
not run and completed its testing.
■
The upper right hand corner of the
display shows the number of the code
currently being displayed, the total
number of codes retrieved, the type
of code (G = Generic; M =
Manufacturer Specific), and whether
or not the displayed code commanded the MIL on. If the code being displayed is a PENDING code, the PENDING icon is shown.
21
Using the Code Reader
CODE RETRIEVAL PROCEDURE
Freeze Frame data is always associated with the
“Priority Code” (identified as Code #1 in the Code
Reader’s display). If the FREEZE FRAME icon is lit
when the “Priority Code” (Code #1) is displayed on the
Code Reader’s screen, it indicates that there is Freeze
Frame data associated with this code, and the vehicle’s
computer has saved it in its memory.
■
The Diagnostic Trouble Code (DTC) and related code definition
are shown in the lower section of the LCD display.
In the case of long code definitions, a small arrow is
shown in the upper/lower right-hand corner of the code
display area to indicate the presence of additional information. Use the SCROLL
button, as necessary, to
view the additional information. When the end of the
screen is reached, pressing the button again returns to
the top of the screen.
8. Read and interpret Diagnostic Trouble Codes/system condition
using the LCD display and the green, yellow and red LEDs.
The green, yellow and red LEDs are used (with the LCD
display) as visual aids to make it easier to determine
engine system conditions.
■
Green LED – Indicates that all
engine systems are “OK” and operating normally. All monitors supported
by the vehicle have run and performed their diagnostic testing, and
no trouble codes are present. A zero
will show on the Code Reader’s LCD
display, and all Monitor icons will be
solid.
■
Yellow LED – Indicates one of the following conditions:
A. A PENDING CODE IS PRESENT – If
the yellow LED is illuminated, it may
indicate a Pending code is present.
Check the Code Reader’s LCD display for confirmation. A Pending code
is confirmed by the presence of a
numeric code and the word PENDING on the Code Reader’s LCD display.
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OBD2
Using the Code Reader
CODE RETRIEVAL PROCEDURE
B. MONITOR NOT RUN STATUS – If the
Code Reader’s LCD display shows a
zero (indicating there are no DTC’s
present in the vehicle’s computer
memory), but the yellow LED is illuminated, it may be an indication that
some of the Monitors supported by
the vehicle have not yet run and completed their diagnostic testing. Check
the Code Reader’s LCD display for confirmation. All Monitor
icons that are blinking have not yet run and completed their
diagnostic testing; all Monitor icons that are solid have run and
completed their diagnostic testing.
■
Red LED – Indicates there is a problem with one or more of the vehicle’s
systems. The red LED is also used to
indicate that DTC(s) are present (displayed on the Code Reader’s screen).
In this case, the Multifunction Indicator
(Check Engine) lamp on the vehicle’s
instrument panel will be illuminated.
■
DTC’s that start with “P0”, “P2” and some “P3” are considered
Generic (Universal). All Generic DTC definitions are the same on
all OBD2 equipped vehicles. The Code Reader automatically displays the code definitions for Generic DTC’s.
■ DTC’s that start with “P1” and some
“P3” are Manufacturer Specific codes
and their code definitions vary with
each vehicle manufacturer. When a
Manufacturer Specific DTC is retrieved, the LCD display shows a list of
vehicle manufacturers. Use the
SCROLL
button, as necessary, to highlight the appropriate
manufacturer, then press the ENTER/FF
button to display
the correct code definition for your vehicle.
When the last manufacturer in the list is reached, pressing
the SCROLL
button again will return to the first manufacturer in the list.
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23
Using the Code Reader
CODE RETRIEVAL PROCEDURE
If the manufacturer for your vehicle is not listed, use the
SCROLL
button, as necessary, to select Other manufacturer and press the ENTER/FF
button for additional DTC information.
If the Manufacturer Specific
definition for the currently displayed code is not available, an
advisory message shows on
the Code Reader’s LCD display.
9. If more than one code was retrieved press the DTC SCROLL
button, as necessary, to display additional codes one at a time.
■
Whenever the Scroll function is used to view additional codes,
the Code Reader’s communication link with the vehicle’s computer disconnects. To re-establish communication, press the
LINK
button again.
10. Freeze Frame Data (if available) can be viewed at any time (except
MENU mode) by pressing the ENTER/FF
button.
■
In OBD2 systems, when an emissions-related engine malfunction occurs that causes a DTC to set, a record or snapshot of
engine conditions at the time that the malfunction occurred is
also saved in the vehicle’s computer
memory. The record saved is called
Freeze Frame data. Saved engine
conditions include, but are not limited
to: engine speed, open or closed
loop operation, fuel system commands, coolant temperature, calculated load value, fuel pressure, vehicle speed, air flow rate, and
intake manifold pressure.
If more than one malfunction is present that causes more
than one DTC to be set, only the code with the highest priority will contain Freeze Frame data. The code designated
“01” on the Code Reader display is referred to as the
PRIORITY code, and Freeze Frame data always refers to
this code. The priority code is also the one that has commanded the MIL on.
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OBD2
Using the Code Reader
ERASING DIAGNOSTIC TROUBLE CODES (DTCs)
If Freeze Frame data is not
available for the code shown
on the LCD display when the
ENTER/FF
button is
pressed, an advisory message
shows on the LCD display.
Press the DTC SCROLL
button to return to the previous
code display.
11. Determine engine system(s) condition by viewing the Code
Reader’s LCD display for any retrieved Diagnostic Trouble Codes
and code definitions, and interpreting the green, yellow and red
LEDs.
■
If DTC’s were retrieved and you are going to perform the repairs
yourself, proceed by consulting the Vehicle’s Service Repair
Manual for testing instructions, testing procedures, and flow
charts related to retrieved code(s).
■ If you plan to take the vehicle to a professional to have it serviced, complete the Preliminary Vehicle Diagnosis Worksheet
on page 14 and take it together with the retrieved codes, freeze
frame data and LED information to aid in the troubleshooting
procedure.
■ To prolong battery life, the Code Reader automatically shuts
“Off” approximately three minutes after it is disconnected from
the vehicle. The DTCs retrieved and Monitor Status will remain in
the Code Reader’s memory, and may be viewed at any time by
turning the unit “On”. If the Code Reader is re-linked to a vehicle
to retrieve codes/data, any prior codes/data in its memory are
automatically cleared.
The Diagnostic information retrieved can be transferred to
a personal computer (PC) with the use of an optional TekLink program. See documentation that comes with program for instructions.
ERASING DIAGNOSTIC TROUBLE CODES (DTCs)
When the Code Reader’s ERASE function is used to erase
DTCs from the vehicle's on-board computer, "Freeze
Frame" data and manufacturer-specific enhanced data
are also erased.
If you plan to take the vehicle to a Service Center for repair, DO NOT
erase the codes from the vehicle's computer. If the codes are erased,
valuable information that might help the technician troubleshoot the
problem will also be erased.
Erase DTCs from the computer's memory as follows:
OBD2
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Using the Code Reader
ERASING DIAGNOSTIC TROUBLE CODES (DTCs)
When DTCs are erased from the vehicle's computer memory, the I/M Readiness Monitor Status program resets the status of all Monitors to a not run "flashing" condition. To set all
of the Monitors to a DONE status, an OBD 2 Drive Cycle
must be performed. Refer to your vehicle's service manual for
information on how to perform an OBD 2 Drive Cycle for the
vehicle under test.
The Code Reader must be connected to the vehicle’s DLC to
erase the codes from the computer’s memory. If you press the
ERASE
button when the
Code Reader is not connected to
the vehicle’s DLC, the erase
instruction screen displays.
1. If not connected already, connect the
Code Reader to the vehicle's DLC, and
turn the ignition "On.” (If the Code Reader
is already connected and linked to the
vehicle's computer, proceed directly to
step 3. If not, continue to step 2.)
2. Perform the Code Retrieval procedure
as described on page 19. Wait until the
codes are displayed on the Code
Readers LCD and then proceed to step
3.
3. Press and release the ERASE
button. A confirmation message shows on
the LCD display.
- If you are sure you want to proceed press the ERASE
again to erase DTCs from the vehicle’s computer.
button
- If you do not want to continue with the erase process, press the
POWER/LINK
button to exit the erase mode.
4. If you chose to erase DTCs, a progress screen displays while the
erase function is in progress.
■
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When the erase process has completed, the Code Reader automatically re-links to the vehicle, and displays any new information retrieved. Some of the Monitor icons will be flashing to indicate that the Monitors have been re-set.
OBD2
Using the Code Reader
I/M READINESS TESTING
Erasing DTCs does not fix the problem(s) that caused the
code(s) to be set. If proper repairs to correct the problem that
caused the code(s) to be set are not made, the code(s) will
appear again (and the check engine light will illuminate) as
soon as the vehicle is driven long enough for its Monitors to
complete their testing.
I/M READINESS TESTING
I/M is an Inspection and Maintenance program legislated by the
Government to meet federal clean-air standards.
The program requires that a vehicle be taken periodically to an
Emissions Station for an "Emissions Test" or "Smog Check,” where the
emissions-related components and systems are inspected and tested
for proper operation. Emissions Tests are generally performed once a
year, or once every two years.
On OBD 2 systems, the I/M program is enhanced by requiring vehicles to
meet stricter test standards. One of the tests instituted by the Federal
Government is called I/M 240. On I/M 240, the vehicle under test is driven under different speeds and load conditions on a dynamometer for 240
seconds, while the vehicle's emissions are measured.
Emissions tests vary depending on the geographic or regional area in which the vehicle is registered. If the vehicle is registered in a highly urbanized area, the I/M 240 is probably the
type of test required. If the vehicle is registered in a rural area,
the stricter “dynamometer type” test may not be required.
I/M Readiness Monitors
I/M Readiness shows whether the various emissions-related systems
on the vehicle are operating properly and are ready for Inspection and
Maintenance testing.
State and Federal Governments enacted Regulations, Procedures and
Emission Standards to ensure that all emissions-related components
and systems are continuously or periodically monitored, tested and
diagnosed whenever the vehicle is in operation. It also requires vehicle manufacturers to automatically detect and report any problems or
faults that may increase the vehicle's emissions to an unacceptable level.
The vehicle's emissions control system consists of several components or sub-systems (Oxygen Sensor, Catalytic Converter, EGR, Fuel
System, etc.) that aid in reducing vehicle emissions.
To have an efficient Vehicle Emission Control System, all the emissions-related components and systems must work correctly whenever
the vehicle is in operation.
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Using the Code Reader
I/M READINESS TESTING
To comply with State and Federal Government regulations, vehicle
manufacturers designed a series of special computer programs called
"Monitors" that are programmed into the vehicle's computer. Each of
these Monitors is specifically designed to run tests and diagnostics on
a specific emissions-related component or system (Oxygen Sensor,
Catalytic Converter, EGR Valve, Fuel System, etc.) to ensure their
proper operation. Currently, there are a maximum of eleven Monitors
available for use.
To learn more about Emissions Inspection and Maintenance
(I/M) Readiness Monitors, see OBD 2 MONITORS on page 42.
Each Monitor has a specific function to test
and diagnose only its designated emissionsrelated component or system. The names of the
Monitors (Oxygen Sensor Monitor, Catalyst
Monitor, EGR Monitor, Misfire Monitor, etc.)
describe which component or system each Monitor
is designed to test and diagnose.
Emissions Inspection and Maintenance (I/M) Readiness
Monitor Status Information
I/M Readiness Monitor Status shows which of the vehicle's Monitors
have run and completed their diagnosis and testing, and which ones
have not yet run and completed testing and diagnosis of their designated sections of the vehicle's emissions system.
■
If a Monitor was able to meet all the conditions required to enable it
to perform the self-diagnosis and testing of its assigned engine system, it means the monitor "HAS RUN.”
■
If a Monitor has not yet met all the conditions required for it to perform the self-diagnosis and testing of its assigned engine system; it
means the Monitor "HAS NOT RUN.”
The Monitor Run/Not Run status does not show whether
or not a problem exists in a system. Monitor status only
indicates whether a particular Monitor has or has not run
and performed the self-diagnosis and testing of its associated system.
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OBD2
Using the Code Reader
I/M READINESS TESTING
Performing I/M Readiness Quick Check
When a vehicle first comes from the factory, all Monitors indicate a “HAVE RUN” status. This indicates that all Monitors
have run and completed their diagnostic testing. The “HAVE
RUN” status remains in the computer's memory, unless the
Diagnostic Trouble Codes are erased or the vehicle's computer memory is cleared.
The Code Reader allows you to retrieve Monitor/System Status Information to help you determine if the vehicle is ready for an Emissions
Test (Smog Check). In addition to retrieving Diagnostic Trouble Codes,
the Code Reader also retrieves Monitor Run/Not Run status. This information is very important since different areas of the state/country have
different emissions laws and regulations concerning Monitor Run/Not
Run status.
Before an Emissions Test (Smog Check) can be performed, your vehicle must meet certain rules, requirements and procedures legislated
by the Federal and state (country) governments where you live.
1. In most areas, one of the requirements that must be met before a
vehicle is allowed to be Emissions Tested (Smog Checked) is that
the vehicle does not have any Diagnostic Trouble Codes present
(with the exception of PENDING Diagnostic Trouble Codes).
2. In addition to the requirement that no Diagnostic Trouble Codes be
present, some areas also require that all the Monitors that a particular vehicle supports indicate a "Has Run" status condition before
an Emissions Check may be performed.
3. Other areas may only require that some (but not all) Monitors indicate a "Has Run" status before an Emissions Test (Smog Check)
may be performed.
Monitors with a "Has Run" status indicate that all the
required conditions they needed to perform diagnosis
and testing of their assigned engine area (system) have
been met, and all diagnostic testing has completed successfully.
Monitors with a "Has Not Run" status have not yet met
the conditions they need to perform diagnosis and testing of their assigned engine area (system), and have not
been able to perform diagnostic testing on that system.
The green, yellow and red LEDs provide a quick way to help you determine if a vehicle is ready for an Emissions Test (Smog Check). Follow
the instructions below to perform the Quick Check.
Perform the Code Retrieval Procedure as described on page 19,
then interpret the LED indications as follows:
OBD2
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Using the Code Reader
I/M READINESS TESTING
Interpreting I/M Readiness Test Results
1. GREEN LED - Indicates that all engine
systems are "OK" and operating normally (all Monitors supported by the
vehicle have run and performed their
self-diagnostic testing). The vehicle is
ready for an Emissions Test (Smog
Check), and there is a good possibility
that it can be certified.
2. YELLOW LED - Determine from the Code Retrieval Procedure
(page 19) which of the two possible conditions is causing the yellow
LED to light.
■
If a "PENDING" Diagnostic Trouble
Code is causing the yellow LED to
light, it is possible that the vehicle will
be allowed to be tested for emissions
and certified. Currently, most areas
(states / countries) will allow an
Emissions Test (Smog Check) to be
performed if the only code in the vehicle's computer is a "PENDING"
Diagnostic Trouble Code.
■
If the illumination of the Yellow LED is
being caused by monitors that “have
not run” their diagnostic testing, then
the issue of the vehicle being ready
for an Emissions Test (Smog Check)
depends on the emissions regulations and laws of your local area.
- Some areas require that all Monitors indicate a "Has Run" status before they allow an Emissions Test (Smog Check) to be
performed. Other areas only require that some, but not all,
Monitors have run their self-diagnostic testing before an
Emissions Test (Smog Check) may be performed.
From the code retrieval procedure, determine the status of
each Monitor (a solid Monitor icon shows Monitor "Has Run"
status, a flashing Monitor icon indicates "Has Not Run" status). Take this information to an emissions professional to
determine (based on your test results) if your vehicle is ready
for an Emissions Test (Smog Check).
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OBD2
Using the Code Reader
I/M READINESS TESTING
3. RED LED - Indicates there is a problem
with one or more of the vehicle's systems. A vehicle displaying a red LED is
definitely not ready for an Emissions
Test (Smog Check). The red LED is also
an indication that there are Diagnostic
Trouble Code(s) present (displayed on
the Code Reader's screen). The
Multifunction Indicator (Check Engine)
Lamp on the vehicle's instrument panel will light steady. The problem that is causing the red LED to light must be repaired before an
Emissions Test (Smog Check) can be performed. It is also suggested that the vehicle be inspected/repaired before driving the vehicle
further.
If the Red LED was obtained, there is a definite problem present in
the system(s). In these cases, you have the following options.
■
Repair the vehicle yourself. If you are going to perform the
repairs yourself, proceed by reading the vehicle service manual
and following all its procedures and recommendations.
■
Take the vehicle to a professional to have it serviced. The problem(s) causing the red LED to light must be repaired before the
vehicle is ready for an Emissions Test (Smog Check).
Using the I/M Readiness Monitor Status to Confirm a Repair
The I/M Readiness Monitor Status function can be used (after repair of
a fault has been performed) to confirm that the repair has been performed correctly, and/or to check for Monitor Run Status. Use the following procedure to determine I/M Readiness Monitor Status:
1. Using retrieved Diagnostic Trouble Codes (DTCs) and code definitions as a guide, and following manufacturer's repair procedures,
repair the fault or faults as instructed.
2. After the fault or faults have been repaired, connect the Code
Reader to the vehicle's DLC and erase the code or codes from the
vehicle's computer memory.
■
See page 25 for procedures to erase DTCs from the vehicle's onboard computer.
■
Write the codes down on a piece of paper for reference before
erasing.
3. After the erase procedure is performed, most of the Monitor icons
on the Code Reader’s LCD display will be flashing. Leave the Code
Reader connected to the vehicle, and perform a Trip Drive Cycle for
each "flashing" Monitor:
Misfire, Fuel and Comprehensive Component Monitors run
continuously and their icons will always be on solid, even
after the erase function is performed.
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Using the Code Reader
I/M READINESS TESTING
■
Each DTC is associated with a specific Monitor. Consult the vehicle's service manual to identify the Monitor (or Monitors) associated with the faults that were repaired. Follow the manufacturer's
procedures to perform a Trip Drive Cycle for the appropriate
Monitors.
■
While observing the Monitor icons on the Code Reader’s LCD
display, perform a Trip Drive Cycle for the appropriate Monitor or
Monitors.
If the vehicle needs to be driven in order to perform a Trip
Drive Cycle, ALWAYS have a second person help you.
One person should drive the vehicle while the other person observes the Monitor icons on the Code Reader for
Monitor RUN status. Trying to drive and observe the
Code Reader at the same time is dangerous, and could
cause a serious traffic accident.
4. When a Monitor's Trip Drive Cycle is performed properly, the
Monitor icon on the Code Reader’s LCD display changes from
"flashing" to "solid,” indicating that the Monitor has run and finished
its diagnostic testing.
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■
If, after the Monitor has run, the MIL on the vehicle's dash is not
lit, and no stored or pending codes associated with that particular Monitor are present in the vehicle's computer, the repair was
successful.
■
If, after the Monitor has run, the MIL on the vehicle's dash lights
and/or a DTC associated with that Monitor is present in the vehicle's computer, the repair was unsuccessful. Refer to the vehicle's service manual and recheck repair procedures.
OBD2
Onboard Diagnostics
COMPUTER ENGINE CONTROLS
COMPUTER ENGINE CONTROLS
The Introduction of Electronic Engine Controls
Electronic Computer Control Systems make it possible
for vehicle manufacturers to comply with the tougher emissions and fuel efficiency standards mandated by
State and Federal Governments.
As a result of increased air pollution (smog) in large
cities, such as Los Angeles, the California Air Resources
Board (CARB) and the Environmental Protection Agency
(EPA) set new regulations and air pollution standards to
deal with the problem. To further complicate matters, the
energy crisis of the early 1970s caused a sharp increase in
fuel prices over a short period. As a result, vehicle manufacturers were not only required to comply with the new emissions standards, they also had to make their vehicles more fuelefficient. Most vehicles were required to meet a miles-per-gallon
(MPG) standard set by the U.S. Federal Government.
Precise fuel delivery and spark timing are needed to reduce vehicle
emissions. Mechanical engine controls in use at the time (such as ignition points, mechanical spark advance and the carburetor) responded
too slowly to driving conditions to properly control fuel delivery and
spark timing. This made it difficult for vehicle manufacturers to meet
the new standards.
A new Engine Control System had to be designed and integrated with
the engine controls to meet the stricter standards. The new system had
to:
■
Respond instantly to supply the proper mixture of air and fuel for
any driving condition (idle, cruising, low-speed driving, high-speed
driving, etc.).
■
Calculate instantly the best time to “ignite” the air/fuel mixture for
maximum engine efficiency.
■
Perform both these tasks without affecting vehicle performance or
fuel economy.
Vehicle Computer Control Systems can perform millions of calculations each second. This makes them an ideal substitute for the slower
mechanical engine controls. By switching from mechanical to electronic engine controls, vehicle manufacturers are able to control fuel
delivery and spark timing more precisely. Some newer Computer
Control Systems also provide control over other vehicle functions,
such as transmission, brakes, charging, body, and suspension systems.
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Onboard Diagnostics
COMPUTER ENGINE CONTROLS
The Basic Engine Computer Control System
The Computer Control System consists of an on-board
computer and several related control devices (sensors,
switches, and actuators).
The on-board computer is the heart of the Computer
Control System. The computer contains several programs
with preset reference values for air/fuel ratio, spark or ignition timing, injector pulse width, engine speed, etc.
Separate values are provided for various driving conditions,
such as idle, low speed driving, high-speed driving, low load,
or high load. The preset reference values represent the ideal
air/fuel mixture, spark timing, transmission gear selection,
etc., for any driving condition. These values are programmed by the
vehicle manufacturer, and are specific to each vehicle model.
Most on-board computers are located inside the vehicle behind the
dashboard, under the passenger’s or driver’s seat, or behind the right
kick panel. However, some manufacturers may still position it in the
engine compartment.
Vehicle sensors, switches, and actuators are located throughout the
engine, and are connected by electrical wiring to the on-board
computer. These devices include oxygen sensors, coolant temperature sensors, throttle position sensors, fuel injectors, etc. Sensors and
switches are input devices. They provide signals representing current
engine operating conditions to the computer. Actuators are output
devices. They perform actions in response to commands received
from the computer.
The on-board computer receives information inputs from sensors and
switches located throughout the engine. These devices monitor critical
engine conditions such as coolant temperature, engine speed, engine
load, throttle position, air/fuel ratio etc.
TYPICAL COMPUTER
CONTROL SYSTEM
OUTPUT DEVICES
Fuel Injectors
Idle Air Control
EGR Valve
Ignition Module
On-Board
Computer
INPUT DEVICES
Coolant Temperature Sensor
Throttle Position Sensor
Fuel Injectors
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INPUT DEVICES
Oxygen Sensors
OBD2
Onboard Diagnostics
COMPUTER ENGINE CONTROLS
The computer compares the values received from these sensors with
its preset reference values, and makes corrective actions as needed
so that the sensor values always match the preset reference values for
the current driving condition. The computer makes adjustments by
commanding other devices such as the fuel injectors, idle air control,
EGR valve or Ignition Module to perform these actions.
Vehicle operating conditions are constantly changing. The computer
continuously makes adjustments or corrections (especially to the
air/fuel mixture and spark timing) to keep all the engine systems operating within the preset reference values.
On-Board Diagnostics - First Generation (OBD 1)
With the exception of some 1994 and 1995 vehicles,
most vehicles from 1982 to 1995 are equipped with
some type of first generation On-Board Diagnostics.
Beginning in 1988, California’s Air Resources Board
(CARB), and later the Environmental Protection Agency
(EPA) required vehicle manufacturers to include a selfdiagnostic program in their on-board computers. The program would be capable of identifying emissions-related faults
in a system. The first generation of Onboard Diagnostics
came to be known as OBD 1.
OBD 1 is a set of self-testing and diagnostic instructions programmed into the vehicle’s on-board computer. The programs are
specifically designed to detect failures in the sensors, actuators,
switches and wiring of the various vehicle emissions-related systems.
If the computer detects a failure in any of these components or systems, it lights an indicator on the dashboard to alert the driver. The indicator lights only when an emissions-related problem is detected.
The computer also assigns a numeric code for each specific problem
that it detects, and stores these codes in its memory for later retrieval.
These codes can be retrieved from the computer’s memory with the
use of a “Code Reader” or a “Scan Tool.”
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Onboard Diagnostics
COMPUTER ENGINE CONTROLS
On-Board Diagnostics - Second Generation (OBD 2)
In addition to performing all the functions of the OBD 1 System, the OBD 2
The OBD 2 System is
System has been enhanced with new
an enhancement of the
Diagnostic Programs. These programs
OBD 1 System.
closely monitor the functions of various emissions-related components
and systems (as well as other systems) and make this information readily available (with
the proper equipment) to the technician for evaluation.
The California Air Resources Board (CARB) conducted
studies on OBD 1 equipped vehicles. The information that
was gathered from these studies showed the following:
■
A large number of vehicles had deteriorating or degraded
emissions-related components. These components were
causing an increase in emissions.
■
Because OBD 1 systems only detect failed components, the
degraded components were not setting codes.
■
Some emissions problems related to degraded components only
occur when the vehicle is being driven under a load. The emission
checks being conducted at the time were not performed under simulated driving conditions. As a result, a significant number of vehicles with degraded components were passing Emissions Tests.
■
Codes, code definitions, diagnostic connectors, communication
protocols and emissions terminology were different for each manufacturer. This caused confusion for the technicians working on different make and model vehicles.
To address the problems made evident by this study, CARB and the EPA
passed new laws and standardization requirements. These laws required
that vehicle manufacturers to equip their new vehicles with devices capable of meeting all of the new emissions standards and regulations. It was
also decided that an enhanced on-board diagnostic system, capable of
addressing all of these problems, was needed. This new system is known
as “On-Board Diagnostics Generation Two (OBD 2).” The primary
objective of the OBD 2 system is to comply with the latest regulations and
emissions standards established by CARB and the EPA.
The Main Objectives of the OBD 2 System are:
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■
To detect degraded and/or failed emissions-related components or
systems that could cause tailpipe emissions to exceed by 1.5 times
the Federal Test Procedure (FTP) standard.
■
To expand emissions-related system monitoring. This includes a set
of computer run diagnostics called Monitors. Monitors perform diagnostics and testing to verify that all emissions-related components
and/or systems are operating correctly and within the manufacturer’s specifications.
OBD2
Onboard Diagnostics
COMPUTER ENGINE CONTROLS
■
To use a standardized Diagnostic Link Connector (DLC) in all vehicles. (Before OBD 2, DLCs were of different shapes and sizes.)
■
To standardize the code numbers, code definitions and language
used to describe faults. (Before OBD 2, each vehicle manufacturer
used their own code numbers, code definitions and language to
describe the same faults.)
■
To expand the operation of the Malfunction Indicator Lamp (MIL).
■
To standardize communication procedures and protocols between
the diagnostic equipment (Scan Tools, Code Readers, etc.) and the
vehicle’s on-board computer.
OBD 2 Terminology
The following terms and their definitions are related to OBD 2 systems.
Read and reference this list as needed to aid in the understanding of
OBD 2 systems.
■
Powertrain Control Module (PCM) - The PCM is the OBD 2
accepted term for the vehicle’s “on-board computer.” In addition to
controlling the engine management and emissions systems, the
PCM also participates in controlling the powertrain (transmission)
operation. Most PCMs also have the ability to communicate with
other computers on the vehicle (ABS, ride control, body, etc.).
■
Monitor - Monitors are “diagnostic routines” programmed into the
PCM. The PCM utilizes these programs to run diagnostic tests, and
to monitor operation of the vehicle’s emissions-related components
or systems to ensure they are operating correctly and within the
vehicle’s manufacturer specifications. Currently, up to eleven
Monitors are used in OBD 2 systems. Additional Monitors will be
added as the OBD 2 system is further developed.
Not all vehicles support all eleven Monitors.
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■
Enabling Criteria - Each Monitor is designed to test and monitor
the operation of a specific part of the vehicle’s emissions system
(EGR system, oxygen sensor, catalytic converter, etc.). A specific
set of “conditions” or “driving procedures” must be met before the
computer can command a Monitor to run tests on its related system. These “conditions” are known as “Enabling Criteria.” The
requirements and procedures vary for each Monitor. Some Monitors
only require the ignition key to be turned “On” for them to run and
complete their diagnostic testing. Others may require a set of complex procedures, such as, starting the vehicle when cold, bringing it
to operating temperature, and driving the vehicle under specific
conditions before the Monitor can run and complete its diagnostic
testing.
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Onboard Diagnostics
COMPUTER ENGINE CONTROLS
■
Monitor Has/Has Not Run - The terms “Monitor has run” or
“Monitor has not run” are used throughout this manual. “Monitor
has run,” means the PCM has commanded a particular Monitor to
perform the required diagnostic testing on a system to ensure the
system is operating correctly (within factory specifications). The
term “Monitor has not run” means the PCM has not yet commanded a particular Monitor to perform diagnostic testing on its
associated part of the emissions system.
■
Trip - A Trip for a particular Monitor requires that the vehicle is being
driven in such a way that all the required “Enabling Criteria” for the
Monitor to run and complete its diagnostic testing are met. The “Trip
Drive Cycle” for a particular Monitor begins when the ignition key is
turned “On.” It is successfully completed when all the “Enabling
Criteria” for the Monitor to run and complete its diagnostic testing
are met by the time the ignition key is turned “Off.” Since each of
the eleven monitors is designed to run diagnostics and testing on a
different part of the engine or emissions system, the “Trip Drive
Cycle” needed for each individual Monitor to run and complete
varies.
■
OBD 2 Drive Cycle - An OBD 2 Drive Cycle is an extended set of
driving procedures that takes into consideration the various types of
driving conditions encountered in real life. These conditions may
include starting the vehicle when it is cold, driving the vehicle at a
steady speed (cruising), accelerating, etc. An OBD 2 Drive Cycle
begins when the ignition key is turned “On” (when cold) and ends
when the vehicle has been driven in such a way as to have all the
“Enabling Criteria” met for all its applicable Monitors. Only those
trips that provide the Enabling Criteria for all Monitors applicable to
the vehicle to run and complete their individual diagnostic tests
qualify as an OBD 2 Drive Cycle. OBD 2 Drive Cycle requirements
vary from one model of vehicle to another. Vehicle manufacturers
set these procedures. Consult your vehicle’s service manual for
OBD 2 Drive Cycle procedures.
Do not confuse a “Trip” Drive Cycle with an OBD 2 Drive
Cycle. A “Trip” Drive Cycle provides the “Enabling Criteria” for
one specific Monitor to run and complete its diagnostic testing. An OBD 2 Drive Cycle must meet the “Enabling Criteria”
for all Monitors on a particular vehicle to run and complete
their diagnostic testing.
■ Warm-up Cycle - Vehicle operation after an engine off period
where engine temperature rises at least 40°F (22°C) from its temperature before starting, and reaches at least 160°F (70°C). The
PCM uses warm-up cycles as a counter to automatically erase a
specific code and related data from its memory. When no faults
related to the original problem are detected within a specified number of warm-up cycles, the code is erased automatically.
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OBD2
Onboard Diagnostics
DIAGNOSTIC TROUBLE CODES (DTCs)
DIAGNOSTIC TROUBLE CODES (DTCs)
Diagnostic Trouble Codes (DTCs) are
meant to guide you to the proper service procedure in the vehicle’s service
manual. DO NOT replace parts based
only on DTCs without first consulting
the vehicle’s service manual for proper testing procedures for that particular
system, circuit or component.
Diagnostic Trouble
Codes (DTCs) are
codes that identify a
specific problem area.
DTCs are alphanumeric codes that are used to identify a
problem that is present in any of the systems that are monitored by the on-board computer (PCM). Each trouble code
has an assigned message that identifies the circuit, component or system area where the problem was found.
OBD 2 diagnostic trouble codes are made up of five characters:
■
The 1st character is a letter. It identifies the “main system” where
the fault occurred (Body, Chassis, Powertrain, or Network).
■
The 2nd character is a numeric digit. It identifies the “type” of code
(Generic or Manufacturer-Specific).
Generic DTCs are codes that are used by all vehicle manufacturers. The standards for generic DTCs, as well as their
definitions, are set by the Society of Automotive Engineers
(SAE).
Manufacturer-Specific DTCs are codes that are controlled
by the vehicle manufacturers. The Federal Government does
not require vehicle manufacturers to go beyond the standardized generic DTCs in order to comply with the new
OBD2 emissions standards. However, manufacturers are free
to expand beyond the standardized codes to make their systems easier to diagnose.
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■
The 3rd character is a numeric digit. It identifies the specific system or sub-system where the problem is located.
■
The 4th and 5th characters are numeric digits. They identify the
section of the system that is malfunctioning.
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Onboard Diagnostics
DIAGNOSTIC TROUBLE CODES (DTCs)
OBD 2 DTC EXAMPLE
P0201 - Injector Circuit Malfunction, Cylinder 1
B
C
P
U
-
Body
Chassis
Powertrain
Network
0
1
2
3
-
Generic
Manufacturer Specific
Generic
Includes both Generic and Manufacturer
Specific Codes
P0201
Identifies the system where the
problem is located:
1 - Fuel and Air Metering
2 - Fuel and Air Metering (injector circuit
malfunction only)
3 - Ignition System or Misfire
4 - Auxiliary Emission Control System
5 - Vehicle Speed Control and Idle Control
System
6 - Computer Output Circuits
7 - Transmission
8 - Transmission
Identifies what section of the system
is malfunctioning
DTCs and MIL Status
When the vehicle’s on-board computer detects
a failure in an emissions-related component
or system, the computer’s internal diagnostic
program assigns a diagnostic trouble code
(DTC) that points to the system (and subsystem) where the fault was found. The diagnostic program saves the code in the computer’s memory. It records a “Freeze Frame” of
conditions present when the fault was found, and lights the Malfunction
Indicator Lamp (MIL). Some faults require detection for two trips in a
row before the MIL is turned on.
The “Malfunction Indicator Lamp” (MIL) is the accepted term
used to describe the lamp on the dashboard that lights to
warn the driver that an emissions-related fault has been
found. Some manufacturers may still call this lamp a “Check
Engine” or “Service Engine Soon” light.
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Onboard Diagnostics
DIAGNOSTIC TROUBLE CODES (DTCs)
There are two types of DTCs used for emissions-related faults: Type
“A” and Type “B.” Type “A” codes are “One-Trip” codes; Type “B” DTCs
are usually Two-Trip DTCs.
When a Type “A” DTC is found on the First Trip, the following events
take place:
■
The computer commands the MIL “On” when the failure is first
found.
■
If the failure causes a severe misfire that may cause damage to the
catalytic converter, the MIL “flashes” once per second. The MIL
continues to flash as long as the condition exists. If the condition
that caused the MIL to flash is no longer present, the MIL will light
“steady” On.
■
A DTC is saved in the computer’s memory for later retrieval.
■
A “Freeze Frame” of the conditions present in the engine or emissions system when the MIL was ordered “On” is saved in the computer’s memory for later retrieval. This information shows fuel system status (closed loop or open loop), engine load, coolant temperature, fuel trim value, MAP vacuum, engine RPM and DTC priority.
When a Type “B” DTC is found on the First Trip, the following events
take place:
■
The computer sets a Pending DTC, but the MIL is not ordered “On.”
“Freeze Frame” data may or may not be saved at this time depending on manufacturer. The Pending DTC is saved in the computer’s
memory for later retrieval.
■
If the failure is found on the second consecutive trip, the MIL is
ordered “On.” “Freeze Frame” data is saved in the computer’s memory.
■
If the failure is not found on the second Trip, the Pending DTC is
erased from the computer’s memory.
The MIL will stay lit for both Type “A” and Type “B” codes until one of
the following conditions occurs:
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■
If the conditions that caused the MIL to light are no longer present
for the next three trips in a row, the computer automatically turns the
MIL “Off” if no other emissions-related faults are present. However,
the DTCs remain in the computer’s memory as a history code for 40
warm-up cycles (80 warm-up cycles for fuel and misfire faults). The
DTCs are automatically erased if the fault that caused them to be
set is not detected again during that period.
■
Misfire and fuel system faults require three trips with “similar conditions” before the MIL is turned “Off.” These are trips where the
engine load, RPM and temperature are similar to the conditions
present when the fault was first found.
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Onboard Diagnostics
OBD 2 MONITORS
After the MIL has been turned off, DTCs, Freeze Frame data,
and manufacturer-specific enhanced data stay in the computer’s memory. Most of the enhanced data can only be
retrieved with special equipment such as a Scan Tool.
■
Erasing the DTCs from the computer’s memory can also turn off the
MIL. See ERASING DIAGNOSTIC TROUBLE CODES (DTCs) on
page 25, before erasing codes from the computer’s memory. If a
Code Reader or Scan Tool is used to erase the codes, Freeze
Frame data as well as other manufacturer-specific enhanced data
will also be erased.
OBD 2 MONITORS
To ensure the correct operation of the various emissions-related components and systems, a diagnostic program was developed and
installed in the vehicle’s on-board computer. The program has several
procedures and diagnostic strategies. Each procedure or diagnostic
strategy is made to monitor the operation of, and run diagnostic tests
on, a specific emissions-related component or system. These tests
ensure the system is running correctly and is within the manufacturer’s
specifications. On OBD 2 systems, these procedures and diagnostic
strategies are called “Monitors.”
Currently, a maximum of eleven Monitors are used in OBD 2 systems.
Additional monitors may be added as a result of Government regulations as the OBD 2 system grows and matures. Not all vehicles support all eleven Monitors.
Monitor operation is either “Continuous” or “Non-Continuous,”
depending on the specific monitor.
Continuous Monitors
Three of these Monitors are designed to constantly monitor their associated components and/or systems for proper operation. Continuous
Monitors run constantly when the engine is running. The Continuous
Monitors are:
Comprehensive Component Monitor (CCM)
Misfire Monitor
Fuel System Monitor
Non-Continuous Monitors
The other eight Monitors are “non-continuous” Monitors. “Non-continuous” Monitors perform and complete their testing once per trip. The
“non-continuous” Monitors are:
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OBD 2 MONITORS
Oxygen Sensor Monitor
Oxygen Sensor Heater Monitor
Catalyst Monitor
Heated Catalyst Monitor
EGR System Monitor
EVAP System Monitor
Secondary Air System Monitor
Air Conditioning (A/C) Monitor
The following provides a brief explanation of the function of each
Monitor:
Comprehensive Component Monitor (CCM) - This Monitor
continuously checks all inputs and outputs from sensors, actuators, switches and other devices that provide a signal to the computer. The Monitor checks for shorts, opens, out of range value, functionality and “rationality.”
Rationality: Each input signal is compared against all other
inputs and against information in the computer’s memory to
see if it makes sense under the current operating conditions.
Example: The signal from the throttle position sensor indicates the vehicle is in a wide-open throttle condition, but the
vehicle is really at idle, and the idle condition is confirmed by
the signals from all other sensors. Based on the input data,
the computer determines that the signal from the throttle
position sensor is not rational (does not make sense when
compared to the other inputs). In this case, the signal would
fail the rationality test.
The CCM may be either a “One-Trip” or a “Two-Trip” Monitor, depending on the component.
Fuel System Monitor - This Monitor uses a Fuel System Correction program, called Fuel Trim, inside the on-board computer. Fuel Trim is a set of positive and negative values that represent
adding or subtracting fuel from the engine. This program is used to correct for a lean (too much air/not enough fuel) or rich (too much fuel/not
enough air) air-fuel mixture. The program is designed to add or subtract fuel, as needed, up to a certain percent. If the correction needed
is too large and exceeds the time and percent allowed by the program,
a fault is indicated by the computer.
The Fuel System Monitor may be a “One-Trip” or “Two-Trip” Monitor,
depending on the severity of the problem.
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Onboard Diagnostics
OBD 2 MONITORS
Misfire Monitor - This Monitor continuously checks for engine
misfires. A misfire occurs when the air-fuel mixture in the cylinder does not ignite. The misfire Monitor uses changes in crankshaft
speed to sense an engine misfire. When a cylinder misfires, it no
longer contributes to the speed of the engine, and engine speed
decreases each time the affected cylinder(s) misfire. The misfire
Monitor is designed to sense engine speed fluctuations and determine
from which cylinder(s) the misfire is coming, as well as how bad the
misfire is. There are three types of engine misfires, Types 1, 2, and 3.
- Type 1 and Type 3 misfires are two-trip monitor faults. If a fault is
sensed on the first trip, the computer temporarily saves the fault in
its memory as a Pending Code. The MIL is not commanded on at
this time. If the fault is found again on the second trip, under similar
conditions of engine speed, load and temperature, the computer
commands the MIL “On,” and the code is saved in its long term memory.
- Type 2 misfires are the most severe type of misfire. When a Type 2
misfire is sensed on the first trip, the computer commands the MIL
to light when the misfire is sensed. If the computer determines that
a Type 2 misfire is severe , and may cause catalytic converter damage, it commands the MIL to “flash” once per second as soon as the
misfire is sensed. When the misfire is no longer present, the MIL
reverts to steady “On” condition.
Catalyst Monitor - The catalytic converter is a device that is
installed downstream of the exhaust manifold. It helps to oxidize
(burn) the unburned fuel (hydrocarbons) and partially burned fuel (carbon monoxide) left over from the combustion process. To accomplish
this, heat and catalyst materials inside the converter react with the
exhaust gases to burn the remaining fuel. Some materials inside the
catalytic converter also have the ability to store oxygen, and release it
as needed to oxidize hydrocarbons and carbon monoxide. In the
process, it reduces vehicle emissions by converting the polluting
gases into carbon dioxide and water.
The computer checks the efficiency of the catalytic converter by monitoring the oxygen sensors used by the system. One sensor is located
before (upstream of) the converter; the other is located after (downstream of) the converter. If the catalytic converter loses its ability to
store oxygen, the downstream sensor signal voltage becomes almost
the same as the upstream sensor signal. In this case, the monitor fails
the test.
The Catalyst Monitor is a “Two-Trip” Monitor. If a fault is found on the
first trip, the computer temporarily saves the fault in its memory as a
Pending Code. The computer does not command the MIL on at this
time. If the fault is sensed again on the second trip, the computer commands the MIL “On” and saves the code in its long-term memory.
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OBD 2 MONITORS
Heated Catalyst Monitor - Operation of the “heated” catalytic
converter is similar to the catalytic converter. The main difference is that a heater is added to bring the catalytic converter to its
operating temperature more quickly. This helps reduce emissions by
reducing the converter’s down time when the engine is cold. The
Heated Catalyst Monitor performs the same diagnostic tests as the
catalyst Monitor, and also tests the catalytic converter’s heater for
proper operation. This Monitor is also a “Two-Trip” Monitor.
Exhaust Gas Recirculation (EGR) Monitor - The Exhaust
Gas Recirculation (EGR) system helps reduce the formation of
Oxides of Nitrogen during combustion. Temperatures above 2500°F
cause nitrogen and oxygen to combine and form Oxides of Nitrogen in
the combustion chamber. To reduce the formation of Oxides of
Nitrogen, combustion temperatures must be kept below 2500°F. The
EGR system recirculates small amounts of exhaust gas back into the
intake manifold, where it is mixed with the incoming air/fuel mixture.
This reduces combustion temperatures by up to 500°F. The computer
determines when, for how long, and how much exhaust gas is recirculated back to the intake manifold. The EGR Monitor performs EGR system function tests at preset times during vehicle operation.
The EGR Monitor is a “Two-Trip” Monitor. If a fault is found on the first
trip, the computer temporarily saves the fault in its memory as a
Pending Code. The computer does not command the MIL on at this
time. If the fault is sensed again on the second trip, the computer commands the MIL “On,” and saves the code in its long-term memory.
Evaporative System (EVAP) Monitor - OBD 2 vehicles are
equipped with a fuel Evaporative system (EVAP) that helps prevent fuel vapors from evaporating into the air. The EVAP system carries fumes from the fuel tank to the engine where they are burned during combustion. The EVAP system may consist of a charcoal canister,
fuel tank cap, purge solenoid, vent solenoid, flow monitor, leak detector and connecting tubes, lines and hoses.
Fumes are carried from the fuel tank to the charcoal canister by hoses
or tubes. The fumes are stored in the charcoal canister. The computer
controls the flow of fuel vapors from the charcoal canister to the engine
via a purge solenoid. The computer energizes or de-energizes the
purge solenoid (depending on solenoid design). The purge solenoid
opens a valve to allow engine vacuum to draw the fuel vapors from the
canister into the engine where the vapors are burned. The EVAP
Monitor checks for proper fuel vapor flow to the engine, and pressurizes the system to test for leaks. The computer runs this Monitor once
per trip.
The EVAP Monitor is a “Two-Trip” Monitor. If a fault is found on the first
trip, the computer temporarily saves the fault in its memory as a
Pending Code. The computer does not command the MIL on at this
time. If the fault is sensed again on the second trip, the PCM commands the MIL “On,” and saves the code in its long-term memory.
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Onboard Diagnostics
OBD 2 MONITORS
Air Conditioning (A/C) Monitor - The A/C Monitor senses
leaks in air conditioning systems that utilize R-12 refrigerant.
Vehicle manufacturers have been given two options:
1. Use R-12 refrigerant in their A/C systems, and integrate an A/C
Monitor in the OBD 2 systems of these vehicles to detect for refrigerant leaks; or
2. Use R-134 refrigerant instead of R12. The A/C Monitor is not
required on these vehicles.
To date, all vehicle manufacturers have opted to use R-134 in their A/C
systems. As a result, this Monitor has not yet been implemented.
Oxygen Sensor Heater Monitor - The Oxygen Sensor Heater
Monitor tests the operation of the oxygen sensor’s heater. There
are two modes of operation on a computer-controlled vehicle: “openloop” and “closed-loop.” The vehicle operates in open-loop when the
engine is cold, before it reaches normal operating temperature. The
vehicle also goes to open-loop mode at other times, such as heavy
load and full throttle conditions. When the vehicle is running in openloop, the oxygen sensor signal is ignored by the computer for air/fuel
mixture corrections. Engine efficiency during open-loop operation is
very low, and results in the production of more vehicle emissions.
Closed-loop operation is the best condition for both vehicle emissions
and vehicle operation. When the vehicle is operating in closed-loop,
the computer uses the oxygen sensor signal for air/fuel mixture corrections.
In order for the computer to enter closed-loop operation, the oxygen
sensor must reach a temperature of at least 600°F. The oxygen sensor
heater helps the oxygen sensor reach and maintain its minimum operating temperature (600°F) more quickly, to bring the vehicle into
closed-loop operation as soon as possible.
The Oxygen Sensor Heater Monitor is a “Two-Trip” Monitor. If a fault is
found on the first trip, the computer temporarily saves the fault in its
memory as a Pending Code. The computer does not command the
MIL on at this time. If the fault is sensed again on the second trip, the
computer commands the MIL “On,” and saves the code in its long-term
memory.
Oxygen Sensor Monitor - The Oxygen Sensor monitors how
much oxygen is in the vehicle’s exhaust. It generates a varying
voltage of up to one volt, based on how much oxygen is in the exhaust
gas, and sends the signal to the computer. The computer uses this signal to make corrections to the air/fuel mixture. If the exhaust gas has
a large amount of oxygen (a lean air/fuel mixture), the oxygen sensor
generates a “low” voltage signal. If the exhaust gas has very little oxygen (a rich mixture condition), the oxygen sensor generates a “high”
voltage signal. A 450mV signal indicates the most efficient, and least
polluting, air/fuel ratio of 14.7 parts of air to one part of fuel.
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OBD 2 MONITORS
The oxygen sensor must reach a temperature of at least 600-650°F,
and the engine must reach normal operating temperature, for the computer to enter into closed-loop operation. The oxygen sensor only functions when the computer is in closed-loop. A properly operating oxygen
sensor reacts quickly to any change in oxygen content in the exhaust
stream. A faulty oxygen sensor reacts slowly, or its voltage signal is
weak or missing.
The oxygen sensor is a “Two-Trip” monitor. If a fault is found on the first
trip, the computer temporarily saves the fault in its memory as a
Pending Code. The computer does not command the MIL on at this
time. If the fault is sensed again on the second trip, the computer commands the MIL “On,” and saves the code in its long-term memory.
Secondary Air System Monitor - When a cold engine is first
started, it runs in open-loop mode. During open-loop operation,
the engine usually runs rich. A vehicle running rich wastes fuel and
creates increased emissions, such as carbon monoxide and some
hydrocarbons. A Secondary Air System injects air into the exhaust
stream to aid catalytic converter operation:
1. It supplies the catalytic converter with the oxygen it needs to oxidize
the carbon monoxide and hydrocarbons left over from the combustion process during engine warm-up.
2. The extra oxygen injected into the exhaust stream also helps the
catalytic converter reach operating temperature more quickly during warm-up periods. The catalytic converter must heat to operating temperature to work properly.
The Secondary Air System Monitor checks for component integrity and
system operation, and tests for faults in the system. The computer runs
this Monitor once per trip.
The Secondary Air System Monitor is a “Two-Trip” monitor. If a fault is
found on the first trip, the computer temporarily saves this fault in its
memory as a Pending Code. The computer does not command the
MIL on at this time. If the fault is sensed again on the second trip, the
computer commands the MIL “On,” and saves the code in its long-term
memory.
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OBD 2 MONITORS
OBD 2 Reference Table
The table below lists current OBD 2 Monitors, and indicates the following for each Monitor:
A. Monitor Type (how often does the Monitor run; Continuous or Once
per trip)
B. Number of trips needed, with a fault present, to set a pending DTC
C. Number of consecutive trips needed, with a fault present, to command the MIL “On” and store a DTC
D. Number of trips needed, with no faults present, to erase a Pending
DTC
E. Number and type of trips or drive cycles needed, with no faults
present, to turn off the MIL
F. Number of warm-up periods needed to erase the DTC from the
computer’s memory after the MIL is turned off
Name of
Monitor
B
C
D
E
F
Comprehensive
Continuous
Component Monitor
1
2
1
3
40
Misfire Monitor
(Type 1 and 3)
Continuous
1
2
1
3 - similar
conditions
80
Misfire Monitor
(Type 2)
Continuous
3 - similar
conditions
80
Fuel System
Monitor
Continuous
1
1 or 2
1
3 - similar
conditions
80
Catalytic Converter
Monitor
Once per
trip
1
2
1
3 trips
40
Oxygen Sensor
Monitor
Once per
trip
1
2
1
3 trips
40
Oxygen Sensor
Heater Monitor
Once per
trip
1
2
1
3 trips
40
Exhaust Gas
Recirculation (EGR)
Monitor
Once per
trip
1
2
1
3 trips
40
Evaporative
Emissions Controls
Monitor
Once per
trip
1
2
1
3 trips
40
Secondary Air
System (AIR)
Monitor
Once per
trip
1
2
1
3 trips
40
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OBD2
Glossary
GLOSSARY OF TERMS AND ABBREVIATIONS
GLOSSARY OF TERMS AND ABBREVIATIONS
CARB – California Air Resources Board
CCM – Continuous Component Monitor
Computer Control System – An electronic control system, consisting
of an on-board computer and related sensors, switches and actuators,
used to ensure peak performance and fuel efficiency while reducing
pollutants in the vehicle’s emissions.
DIY – Do-It-Yourself
DLC – Data Link Connector
Drive Cycle – An extended set of driving procedures that takes into
consideration the various types of driving conditions encountered in
real life.
Driving Condition – A specific environmental or operation condition
under which a vehicle is operated; such as starting the vehicle when
cold, driving at steady speed (cruising), accelerating, etc.
DTC(s) – Diagnostic Trouble Code(s)
EGR – Exhaust Gas Recirculation
EPA – Environmental Protection Agency
EVAP – Evaporative Emissions System
Fault Code – See DTCs
Freeze Frame – A digital representation of engine and/or emissions
system conditions present when a fault code was recorded.
FTP – Fuel Tank Pressure
Generic Code – A DTC that applies to all OBD 2 compliant vehicles.
I/M Readiness – An indication of whether or not a vehicle’s emissionsrelated system are operating properly and are ready for Inspection and
Maintenance testing.
I/M Test / Emissions Test / Smog Check – A functional test of a vehicle to determine if tailpipe emissions are within Federal/State/Local
requirements.
LCD – Liquid Crystal Display
LED – Light Emitting Diode
LTFT – Long Term Fuel Trim, is a program in the vehicle’s computer
designed to add or subtract fuel from the vehicle to compensate for
operating conditions that vary from the ideal A/F ratio (long term).
Manufacturer Specific Code – A DTC that applies only to OBD 2
compliant vehicles made by a specific manufacturer.
MIL – Malfunction Indicator Lamp (also referred to as “Check Engine”
light
OBD2
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49
Glossary
GLOSSARY OF TERMS AND ABBREVIATIONS
OBD 1 – On-Board Diagnostics Version 1 (also referred to as “OBD I”)
OBD 2 – On-Board Diagnostics Version 2 (also referred to as “OBD II”)
On-Board Computer – The central processing unit in the vehicle’s
computer control system.
PCM – Powertrain Control Module
Pending Code – A code recorded on the “first trip” for a “two-trip”
code. If the fault that caused the code to be set is not detected on the
second trip, the code is automatically erased.
STFT – Short Term Fuel Trim, is a program in the vehicle’s computer
designed to add or subtract fuel from the vehicle to compensate for
operating conditions that vary from the ideal A/F ratio. The vehicle uses
this program to make minor fuel adjustments (fine tune) on a shortterm basis.
Trip Drive Cycle – Vehicle operation that provides the necessary driving condition to enable a vehicle Monitor to run and complete its diagnostic testing.
VECI – Vehicle Emission Control Information Decal
50
E
OBD2
Warranty and Servicing
LIMITED ONE YEAR WARRANTY
The Manufacturer warrants to the original purchaser that this unit is
free of defects in materials and workmanship under normal use and
maintenance for a period of one (1) year from the date of original purchase.
If the unit fails within the one (1) year period, it will be repaired or
replaced, at the Manufacturer’s option, at no charge, when returned
prepaid to the Service Center with Proof of Purchase. The sales
receipt may be used for this purpose. Installation labor is not covered
under this warranty. All replacement parts, whether new or remanufactured, assume as their warranty period only the remaining time of this
warranty.
This warranty does not apply to damage caused by improper use, accident, abuse, improper voltage, service, fire, flood, lightning, or other
acts of God, or if the product was altered or repaired by anyone other
than the Manufacturer’s Service Center.
The Manufacturer, under no circumstances shall be liable for any consequential damages for breach of any written warranty of this unit. This
warranty gives you specific legal rights, and you may also have rights,
which vary from state to state. This manual is copyrighted with all rights
reserved. No portion of this document may be copied or reproduced by
any means without the express written permission of the Manufacturer.
THIS WARRANTY IS NOT TRANSFERABLE. For service, send via
U.P.S. (if possible) prepaid to Manufacturer. Allow 3-4 weeks for service/repair.
SERVICE PROCEDURES
If you have any questions, require technical support or information on
UPDATES and OPTIONAL ACCESSORIES, please contact your local
store, distributor or the Service Center.
USA & Canada:
(800) 544-4124 (6AM-6PM, GD\VDZHHN PST)
All others:
(714) 241-6802 (6AM-6PM, 7 days a week, PST)
FAX: (714) 432-3979 (24 hr.)
Web: www.innova.com
OBD2
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51
www.innova.com
®
Innova Electronics Corp.
PRODUCT DESIGN & COPYRIGHT
17352 Von Karman Ave.
Irvine, CA 92614
Printed in Taiwan
Instruction MRP #93-0093 Rev. A
E
© 2012
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