SERVICE BRAKES 35A-1 CONTENTS
35A-1
SERVICE BRAKES
CONTENTS
BASIC BRAKE SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35A
ANTI-SKID BRAKING SYSTEM (ABS) <2WD> . . . . . . . . . . . . . . . . . . . . . . 35B
ACTIVE STABILITY CONTOROL (ASC) SYSTEM . . . . . . . . . . . . . . . . . . . 35C
35A-2
BASIC BRAKE SYSTEM – General/On-vehicle Service
GROUP 35A
BASIC BRAKE SYSTEM
GENERAL
OUTLINE OF CHANGES
The proportioning valve has been discontinued due to the introduction of the Electronic Brake-force
Distribution (EBD) function. In addition, the service specification and procedure have been revised.
D FRONT BRAKE DISC RUN-OUT
D FRONT DISC BRAKE DISASSEMBLY AND REASSEMBLY
ON-VEHICLE SERVICE
BRAKE DISC ROTOR CHECK
For the checking procedure, refer to the Basic Manual.
Front Brake Disc Run-out
Limit: 0.03 mm or less
35A-3
BASIC BRAKE SYSTEM – Front Disc Brake
FRONT DISC BRAKE
DISASSEMBLY AND REASSEMBLY
16
37 Nm
13
14
3
1
4
7.9 Nm
6
10
11
15
12
9
8
1
5
37 Nm
16
14
2
7
6
15
Shim set
3
1
4
6
10
11
16
13
9
10
13
5
4
6
7
1
8
2
6
8
7
Brake caliper kit
Disassembly steps
1. Pin bolt
"AA 2. Guide pin
"AA 3. Lock pin
"AA 4. Bushing
5. Caliper support
6. Pin boot
7. Boot ring
AA"
8. Piston boot
6
12
16
Clip set
Pad set
AA"
AB"
9.
10.
11.
12.
13.
14.
15.
16.
Grease
Seal and boots kit
Piston
Piston seal
Caliper body
Pad and wear indicator assembly
Pad assembly
Inner shim
Outer shim
Pad clip
35A-4
BASIC BRAKE SYSTEM – Front Disc Brake
LUBRICATION POINTS
Piston
seal
Grease: Repair kit grease
Caution
The piston seal inside the
seal and boot kit is coated
with special grease, so do
not wipe this grease off.
Brake fluid: DOT3 or DOT4
Grease: Repair kit grease
Grease: Repair kit grease
DISASSEMBLY SERVICE POINTS
AA" PISTON BOOT/PISTON REMOVAL
Use a piece of wood to protect the caliper body outer side,
and then apply compressed air through the brake hose
connection hole to withdraw the piston and piston boot.
Caution
If air is blown into the caliper body suddenly, the piston
will pop out, causing damage to the caliper body. Be
sure to apply compressed air gradually.
BASIC BRAKE SYSTEM – Front Disc Brake
35A-5
AB" PISTON SEAL REMOVAL
1. Remove the piston seal with finger tip.
Caution
Do not use a flat-tipped screwdriver or other tool to
prevent damage to inner cylinder.
2. Clean piston surface and inner bore with trichloroethylene,
alcohol or the specified brake fluid.
Specified brake fluid: DOT3 or DOT4
REASSEMBLY SERVICE POINT
Bushing and
Lock pin
Bleeder
nipple
"AA BUSHING/LOCK PIN/GUIDE PIN INSTALLATION
Install the bushing and lock pin to the bleeder nipple side
at the caliper body, the guide pin to its opposite side,
respectively.
Guide pin
INSPECTION
Refer to the Basic Manual.
35B-1
ABS <2WD> – General/On-vehicle Service
GROUP 35B
ANTI-SKID BRAKING SYSTEM (ABS) <2WD>
GENERAL
OUTLINE OF CHANGES
The Electronic Brake-force Distribution (EBD) has been adopted. The EBD makes it possible to maintain
the maximum amount of braking force for the rear wheels even when the vehicle’s load is unevenly
distributed.
EBD CONTROL
In ABS, electronic control method is used whereby
the rear wheel brake hydraulic pressure during braking is regulated by rear wheel control solenoid
valves in accordance with the vehicle’s rate of deceleration and the front and rear wheel slippage which
are calculated from the signals received from the
various wheel sensors. EBD control is a control
system which provides a high level of control for
both vehicle braking force and vehicle stability. The
system has the following features.
D Because the system provides the optimum rear
wheel braking force regardless of the vehicle
D
D
laden condition and the condition of the road
surface, the system reduces the required pedal
depression force, particularly when the vehicle
is heavily laden or driving on road surfaces
with high frictional coefficients.
Because the duty placed on the front brakes
has been reduced, the increases in pad temperature can be controlled during front brakes applying to improve the wear resistance characteristics of the pad.
Control valves such as the proportioning valve
are no longer required.
NOTE
Only the description below has been changed due to the introduciton of the EBD. The other service
procedures are the same as before. (Refer to the Basic Manual.)
ON-VEHICLE SERVICE
REMEDY FOR A FLAT BATTERY
When booster cables are used to start the engine when the
battery is completely flat and then the vehicle is immediately
driven without waiting for the battery to recharge itself to
some extent, the engine may misfire, and driving might not
be possible.
This happens because ABS consumes a great amount of
current for its self-check function; the remedy is to allow the
battery to recharge sufficiently.
Caution
Do not drive the vehicle while the ABS is disabled (e.g.
the ABS-ECU connector is disconnected), otherwise
vehicle behaviour will become unstable when braking.
35C-1
ACTIVE STABILITY
CONTROL (ASC)
SYSTEM
CONTENTS
GENERAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Outline of Change . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
MASTER CYLINDER AND BRAKE BOOSTER
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Active Stability Control (ASC) System . . . . . . . . . . 2
Master Cylinder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
SERVICE SPECIFICATIONS . . . . . . . . . . . . . . . . . 4
MOTOR RELAY . . . . . . . . . . . . . . . . . . . . . . . . . . 51
SPECIAL TOOLS . . . . . . . . . . . . . . . . . . . . . . . . . . 4
HYDRAULIC UNIT . . . . . . . . . . . . . . . . . . . . . . . . 51
TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . 5
SENSORS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
ON-VEHICLE SERVICE . . . . . . . . . . . . . . . . . . . 46
ASC SWITCH . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
Master Cylinder Pressure Sensor Check . . . . . . 46
ASC-ECU . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
Solenoid Valve Checks . . . . . . . . . . . . . . . . . . . . . . 47
Motor Operation Check . . . . . . . . . . . . . . . . . . . . . . 47
Valve Relay Continuity Check . . . . . . . . . . . . . . . . 48
35C-2
ASC - General
GENERAL
OUTLINE OF CHANGE
The following service procedures have been established to correspond to the addition of an Active Stability
Control (ASC) system as an option. <2500>
ACTIVE STABILITY CONTROL (ASC) SYSTEM
This system is a safety and accident-prevention system which augments the ABS and TCL functions
by controlling the braking force independently for all four wheels; this controls the longitudinal and lateral
forces applied to the vehicle in order to restrict any dangerous vehicle behaviour when driving under
marginal conditions.
CONSTRUCTION DIAGRAM
<L.H. drive vehicles>
11
13
14
5
1
2
12
10
15
6
8
7
3
9
4
9
<R.H. drive vehicles>
6
2
11
4
12
8
3
9
15
10
5
9
14
13
1
7
ASC - General
35C-3
No.
Name of each component
part
Outline of function
1
ASC control unit (ASC-ECU)
Processes the information from the various sensors to calculate factors such
as the demand yaw moment based on the control model, and uses these
calculations to control the brake hydraulic pressure for the four wheels and the
engine output.
Controls the diagnosis functions and fail-safe functions.
2
Engine control unit
(Engine-ECU)
Sends the signals which are required by the ASC for engine control to the
ASC-ECU.
Carries out corrections in response to the engine condition (such as whether
the engine is cold or warm) based on engine torque reduction requests and
ignition timing retard requests, and also controls the ignition timing.
3
Stop lamp
Sends a signal to the ASC-ECU indicating whether the brake pedal is
depressed or not.
4
Master cylinder pressure sensor
Detects the master cylinder output pressure and inputs this to the ASC-ECU.
5
Accumulator pressure sensor
Detects the accumulator hydraulic pressure and inputs this to the ASC-ECU.
6
Lateral G sensor
Detects the acceleration in the lateral vehicle direction and inputs this to the
ASC-ECU.
7
Yaw rate sensor
Detects the angular velocity of the vehicle and inputs this to the ASC-ECU.
8
Steering sensor
Detects the steering wheel angle signal and inputs this to the ASC-ECU.
9
Wheel speed sensors
Detect the DC signals at frequencies which are proportional to the rotation
speeds of the wheels, and input these to the ASC-ECU.
10
Accelerator pedal position
sensor (APS)
Detects the accelerator pedal depression amount and inputs this to the
ASC-ECU.
11
ASC/TCL operation lamp
Switched off when neither the ASC and TCL function is operating, and
illuminates when either function is operating.
ASC-OFF indication lamp
Illuminates when the ASC and TCL systems are cancelled. (the ASC switch
is at OFF).
In addition, the indicator lamp illuminates when the ASC-ECU fail-safe
function cancels the system.
12
ASC switch
Sends a signal for switching the ASC/TCL control modes (ASC/TCL-ON,
ASC/TCL-OFF) to the ASC-ECU. The ASC-ECU turns the entire system on
and via the switch operation.
13
Motor relay
Turns ON to supply power to the motor inside the hydraulic unit when a signal
is received from the ASC-ECU.
14
Valve relay
Turns ON to supply power to the solenoid valve inside the hydraulic unit when
a signal is received from the ASC-ECU.
15
Diagnosis connector
Outputs diagnosis codes.
NOTE
In the case of component parts which from a part of other systems also, only the functions of that part
which relate to the ASC system are mentioned.
35C-4
SERVICE SPECIFICATIONS
Item
Standard value
Master cylinder pressure sensor output voltage V
Resistance between ABS solenoid valve terminals W
Resistance between ASC solenoid valve terminals W
G sensor output voltage V
Yaw rate sensor output voltage V
Hydraulic pressure 0 MPa
0.4 - 0.6
Hydraulic pressure 9.8 MPa
2.4 - 2.6
Front-right side
Front-left side
Rear-right side
Rear-left side
IN
6.3 - 6.9
OUT
3.1 - 3.4
Diagonal accumulator
valves
FR-RL
3.1 - 3.4
FL-RR
3.1 - 3.4
Diagonal cut valves
FR-RL
6.3 - 6.9
FL-RR
6.3 - 6.9
When horizontal
2.4 - 2.6
When label surface is facing
sideways
3.3 - 3.7
When stationary
2.4 - 2.6
SPECIAL TOOLS
Tool
Number
Name
Use
MB991502
MUT-II
sembly
as-
ASC inspection (diagnosis display using
MUT-II)
MB991529
Diagnosis
code
check harness
ASC inspection (diagnosis display using
ASC/TCL operation lamp and ASC-OFF
indication lamp)
MB991348
Test harness set
Sensor inspection
sub
ASC - Troubleshooting
35C-5
TROUBLESHOOTING
BASIC FLOW FOR TROUBLE DIAGNOSIS
’97 GALANT Workshop Manual - Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service
Points.
NOTE
Check that the followings are normal before judging that there is a problem.
D Is the proper steering wheel installed in the correct position to the centre of the steering column
shaft?
D Are the sizes, specifications, air pressures, balance and wear for the tires and wheels normal?
D Is the wheel alignment normal?
D Have any modifications been made to areas such as the engine or suspension which might have
an effect on the ASC system?
ASC/TCL indication lamp
ASC/TCL
operation lamp
DIAGNOSIS FUNCTION
READING DIAGNOSIS CODES
Use the MUT-II or the following lamp to take a reading of
the diagnosis codes.
(’97 GALANT Workshop Manual - Refer to GROUP 00 How to Use Troubleshooting/Inspection Service Points.)
ABS and ASC diagnosis code: ASC/TCL operation lamp
TCL diagnosis code: ASC-OFF indication lamp
ABS warning lamp
NOTE
(1) Connect the MUT-II to the 16-pin diagnosis connector.
(2) ABS diagnosis codes can be read out by means of the
ABS warning lamp if the valve relay has been removed.
ERASING DIAGNOSIS CODES
’97 GALANT Workshop Manual - Refer to GROUP 00 How to Use Troubleshooting/Inspection Service Points.
35C-6
ASC - Troubleshooting
INSPECTION CHART FOR DIAGNOSIS CODES
Code No.
Diagnosis item
Reference page
11
FR wheel speed sensor (open or short-circuit)
35C-8
12
FL wheel speed sensor (open or short-circuit)
13
RR wheel speed sensor (open or short-circuit)
14
RL wheel speed sensor (open or short-circuit)
15
Wheel speed sensor system (output signal abnormality)
35C-9
16
ECU power supply voltage abnormality
35C-10
17
ASC switch system
35C-11
21
FR wheel speed sensor system
35C-8
22
FL wheel speed sensor system
23
RR wheel speed sensor system
24
RL wheel speed sensor system
25
Rear wheel speed sensor system (open circuit in both left and right sensors)
26
Rear wheel speed sensor system (malfunction in both left and right sensors)
27
Front and rear wheel speed sensor system (open circuit in both front and rear sensors)
31
Ignition switch (IG2) system
35C-12
33
Stop lamp switch system (open circuit or ON problem)
35C-13
35
Steering sensor system (ST-1, 2, N)
35C-14
36
Steering sensor system (ST-N)
35C-15
37
Steering sensor system (ST-1, 2)
35C-15
41
FR solenoid valve system
35C-16
42
FL solenoid valve system
43
RR solenoid valve system
44
RL solenoid valve system
45
FR diagonal cut valve system
46
FL diagonal cut valve system
47
FR diagonal booster valve system
48
FL diagonal booster valve system
51
Valve relay system (ON malfunction)
35C-16
52
Valve relay system (OFF malfunction)
35C-17
53
Motor relay system (OFF malfunction)
35C-17
54
Motor relay system (ON malfunction)
35C-19
35C-12
35C-7
ASC - Troubleshooting
Code No.
Diagnosis item
Reference page
61
Communication system with A/T-ECU
35C-20
63
ECU failure
35C-20
65
APS or TPS system
35C-21
66
TPS or APS system
35C-22
67
APS system
35C-23
71
Lateral G sensor circuit system
35C-24
72
Yaw rate sensor circuit system (open or short-circuit)
35C-24
73
Master cylinder pressure sensor system
35C-25
74
Yaw rate or lateral G sensor system
35C-25
75
Engine-ECU system
35C-26
76
Communication system with engine-ECU
35C-26
77
TCL vacuum or ventilation solenoid valve system
35C-26
78
Accumulator stroke switch system
35C-27
35C-8
ASC - Troubleshooting
INSPECTION PROCEDURE CLASSIFIED BY DIAGNOSIS CODE
Code Nos. 11, 12, 13, 14 Wheel speed sensor system
(open or short-circuit)
Code Nos. 21, 22, 23, 24 Wheel speed sensor system
Probable cause
Code Nos. 11, 12, 13 and 14 are output if an open circuit or short-circuit is
detected in the (+) or (- ) line of one or more of the four wheel speed sensors
because of an open circuit or short-circuit detected by the ASC-ECU hardware
circuit.
D
D
D
Malfunction of wheel speed sensor
Malfunction of harness or connector
Malfunction of ASC-ECU
Code Nos. 21, 22, 23 and 24 are output at the following times.
D If an open circuit cannot be confirmed, but there is no signal input received
from one of the four wheel speed sensors when the vehicle speed is 8 km/h
or higher.
D If a chipped or blocked ABS rotor is detected, or if anti-lock brake control is
continuously engaged because the sensor output drops due to of a sensor
malfunction or a deformed ABS rotor.
D
D
D
D
Malfunction of wheel speed sensor
Malfunction of harness or connector
Malfunction of ABS rotor
Excessive clearance between sensor and ABS
rotor
Malfunction of ASC-ECU
Malfunction of wheel bearing
Check the wheel speed sensor
installation.
OK
Measure at ASC-ECU harness
connector C-180.
D Disconnect the connector and
measure at the harness side.
D Resistance between terminals
32 - 40, 33 - 41, 34 - 42 and
35 - 43.
OK: 1.0 - 1.5 kW
Move the sensor harness and
connector while checking at this
time.
NG
NG
D
D
Repair
Check the wheel speed sensor.
(Refer to GROUP 35B - Wheel
Speed Sensor*.)
NG
Repair
OK
Check the following connectors:
<L.H. drive vehicles>
C-180, C-75, C-115, A-09, C-74,
A-39, C-123, E-11, E-13, E-14, E-12
<R.H. drive vehicles>
C-180, A-41, A-09, C-75, C-115,
A-39, C-121, E-11, E-13, E-14, E-12
OK
NG
Replace
OK
Check the trouble symptoms.
Measure at ASC-ECU harness
connector C-180.
D Disconnect the connector and
measure at the harness side.
D Rotate the tire 1/2 to 1 time per
second.
D Voltage between terminals
32 - 40, 33 - 41, 34 - 42 and
35 - 43.
OK: 42 mV or more (when measured using a multimeter)
120 mV or more (when measured using an oscilloscope)
NG
Check the ABS rotor. (Refer to
GROUP 35B - Wheel Speed
Sensor*.)
OK
Check the wheel bearing.
Refer to GROUP 26 - On-vehicle
Service*.
Refer to GROUP 27 - On-vehicle
Service*.
OK
Check the following connector:
C-180
NG
OK
Repair
Check the trouble symptoms.
NG
Replace the ASC-ECU.
NOTE
*: Refer to ’97 GALANT Workshop Manual.
NG
NG
Check the harness between each
wheel speed sensor and the
ASC-ECU, and repair if necessary.
Replace
35C-9
ASC - Troubleshooting
Code No. 15 Wheel speed sensor system (output signal
abnormality)
Probable cause
This code is output if there is an abnormality (other than an open circuit or
short-circuit) in any of the wheel speed sensor output signals.
D
D
D
D
D
D
Are the tires the same size on all
four wheels?
NO
Incorrect tire sizes for 4 wheels
Incorrect wheel speed sensor installation
Malfunction of wheel speed sensor
Malfunction of ABS rotor
Malfunction of wheel bearing
Malfunction of ASC-ECU
Fit tires of the same size to all four
wheels.
YES
NG
Check the wheel speed sensor
installation.
NG
Check the trouble symptoms.
Repair
OK
Measure at ASC-ECU harness
connector C-180.
D Disconnect the connector and
measure at the harness side.
D Rotate the tire 1/2 to 1 time per
second.
D Voltage between terminals
32 - 40, 33 - 41, 34 - 42 and
35 - 43.
OK: 42 mV or more (when measured using a multimeter)
120 mV or more (when measured using an oscilloscope)
OK
NG
Check the wheel speed sensor.
(Refer to GROUP 35B - Wheel
Speed Sensor*.)
OK
Check the ABS rotor. (Refer to
GROUP 35B - Wheel Speed
Sensor*.)
OK
Check the wheel bearing.
Refer to GROUP 26 - On-vehicle
Service*.
Refer to GROUP 27 - On-vehicle
Service*.
Check the following connector:
C-180
OK
NG
Repair
Check the trouble symptoms.
NG
Replace the ASC-ECU.
NOTE
*: Refer to ’97 GALANT Workshop Manual.
NG
NG
OK
Replace
Replace
Check the harness between each
wheel speed sensor and the
ASC-ECU, and repair if necessary.
35C-10
ASC - Troubleshooting
Code No. 16 ECU power supply voltage abnormality
(when the ABS warning lamp is on)
Probable cause
This code is output if the ASC-ECU power supply voltage or valve relay power
supply voltage drops below or rises above the standard level.
Furthermore, the valve relay power supply voltage is detected from the voltage
at the valve relay monitoring line.
D
D
D
D
Malfunction
Malfunction
Malfunction
Malfunction
of
of
of
of
battery
harness or connector
valve relay
ASC-ECU
Caution
If the battery voltage drops or rises during inspection, this code may be output as a current problem
and correct problem diagnosis may not be possible.
Measure at ASC-ECU connector
C-178.
D Disconnect the connector and
measure at the harness side.
D Start the engine.
D Voltage between terminal 71 and
body earth
OK: System voltage
NG
Check the following connectors:
C-178, C-75, C-66 <L.H. drive
vehicle>, C-134, C-131
OK
Check the trouble symptoms.
NG
NG
Repair
Check the harness between the
ignition switch (IG2) and the
ASC-ECU, and repair if necessary.
OK
Measure at valve relay connector
A-46X.
D Disconnect the connector and
measure at the harness side.
D Ignition switch: ON
(1) Voltage between terminal 1 and
body earth
OK: System voltage
(2) Voltage between terminal 4 and
body earth
OK: System voltage
(1) NG
Check the following connector:
A-46X
OK
Check the trouble symptoms.
(2) NG
Check the following connectors:
<L.H. drive vehicles>
A-46X, C-12, C-113
<R.H. drive vehicles>
A-46X, A-40
OK
OK
Check the trouble symptoms.
Check the valve relay.
(Refer to P.35C-48.)
NG
NG
NG
NG
NG
Repair
Check the harness between the
ignition switch (IG2) and the valve
relay, and repair if necessary.
Repair
Check the harness between fusible
link No. 5 and the valve relay, and
repair if necessary.
Replace
OK
Measure at ASC-ECU connectors
C-178 and C-179.
D Connector connected
D Ignition switch: ON
(1) Voltage between terminal 54 and
body earth
OK: System voltage
(2) Voltage between terminal 73 and
body earth
OK: System voltage
(1) NG
Check the following connectors:
C-179, A-46X
OK
Check the trouble symptoms.
NG
NG
Repair
Check the harness between the
valve relay and the ASC-ECU.
OK
(2) NG
Check the following connectors:
C-178, A-46X
OK
NG
Repair
Replace the ASC-ECU.
OK
Check the trouble symptoms.
NG
Replace the ASC-ECU.
OK
Check the harness between the
valve relay and the ASC-ECU.
OK
Check for a short-circuit in the
harness between the valve relay and
the hydraulic unit and between the
valve relay and the diode C-158.
NG
NG
NG
Repair
Repair
Repair
35C-11
ASC - Troubleshooting
Code No. 16 ECU power supply voltage abnormality (when
the ABS warming lamp is off)
Probable cause
This diagnosis code is output if the ASC-ECU power supply voltage (engine control
relay supply voltage) is lower than the specified value.
If the voltage returns to the specified value or greater, the diagnosis code is erased.
D
D
D
Measure the voltage at ASC-ECU connector C-180.
D Engine: idling
D Disconnect the ASC-ECU connector and measure at the
harness side.
D Between terminal 38 and body earth
OK: 10 V or more
OK
Check the following connector:
C-180
OK
Check trouble symptom.
NG
NG
Check the following connectors:
C-48, C-51, C-180
Malfunction of control relay
Malfunction of harness or connector
Malfunction of ASC-ECU
Replace the ASC-ECU.
NG
Repair
OK
Check trouble symptom.
NG
Inspect the harness between the control relay and the ASC-ECU.
NG
Repair
OK
Engine control relay inspection (Refer to GROUP 13A - On-vehicle
Service.)*
Code No. 17 ASC switch circuit system
Probable cause
This diagnosis code is output if signals are input simultaneously from both the ASC-OFF
and ASC-ON positions because of a short circuit in the ASC switch circuit.
D
D
D
Measure the continuity at ASC switch connector C-98.
D Disconnect the connector and measure at the switch side.
D Between terminals 2 - 3 and 6 - 3
OK: No continuity
NG
Replace the ASC switch.
OK
Check the following connectors:
C-98, C-75, C-178
NG
Repair
OK
Check trouble symptom.
NG
Inspect the harness between the ASC switch and the ASC-ECU.
OK
Replace the ASC-ECU.
NOTE
*:
Refer to ’97 GALANT Workshop Manual.
NG
Malfunction of the ASC switch
Malfunction of harness or connector
Malfunction of ASC-ECU
Repair
35C-12
ASC - Troubleshooting
Code No. 25 Rear wheel speed sensor circuit system
(open circuit in both left and right rear wheel speed
sensors)
Probable cause
Code No. 26 Rear wheel speed sensor circuit system
(malfunction in both rear wheel speed sensors)
Code No. 27 Front and rear wheel speed sensor system
(malfunction in both front and rear wheel speed sensors)
Diagnosis code No. 25 is output if the pulse signal from a rear wheel sensor is
momentarily interrupted (0.02 sec.) because of a transient open circuit in a rear wheel
speed sensor.
Diagnosis code No. 26 is output if a rear wheel speed sensor abnormality is judged
when the turning speed of both rear wheels is 0 km/h for 20 seconds or more while
TCL is operating.
Code No. 27 is displayed if a condition occurs continually where the difference in
the average wheel speed between the front and rear wheels is 20 km/h or more
for 10 seconds.
D
D
D
Malfunction of wheel speed sensor
Malfunction of harness or connector
Malfunction of ASC-ECU
NOTE
(1) If the front wheels only are turning while the rear wheels are stationary (wheel slip), the ASC-OFF
indicator will start flashing after 20 seconds, and the system will be isolated.
(2) When these diagnosis codes are output, erase the diagnosis code memory after carrying out repairs,
and then carry out a road test at 20 km/h or more and check to be sure that the diagnosis codes
are not output again.
Is a diagnosis code output from the wheel speed sensor?
NO
MUT-II Data list
01, 02, 03, 04 Wheel speed sensor
Accelerate from a stationary position.
OK: Vehicle speeds displayed on the speedometer and MUT-II
are identical.
YES
OK
Carry out the troubleshooting regarding the wheel speed sensor
(Refer to P. 35C-8.)
Replace the ASC-ECU.
NG
Check the following connectors:
C-180, C-75, C-115, C-74 <L.H. drive vehicles>, A-41 <R.H. drive
vehicles>, C-123 <L.H. drive vehicles>, C-121 <R.H. drive vehicles>
E-11, E-13
OK
NG
NG
Check trouble symptom.
Repair
Check the harness connectors between the wheel speed sensor
and the ASC-ECU, and repair if necessary.
Code No. 31 Ignition switch (IG2) circuit system
Probable cause
This diagnosis code is output if the IG2 power supply is not distributed, even though
the engine speed is 450 r/min or more.
D
D
Measure the voltage at ASC-ECU connector C-178.
D Ignition switch: ON
D Disconnect the ASC-ECU connector and measure at the
harness side.
D Between terminal 71 and body earth
OK: System voltage
NG
Malfunction of harness or connector
Malfunction of ASC-ECU
Check the following
connecter:
C-178
OK
NG
Replace the ASC-ECU.
OK
Check trouble symptom.
NG
Check the harness between the ignition switch and the ASC-ECU,
and repair if necessary.
Repair
Check trouble symptom.
NG
Check the following connectors:
C-178, C-75, C-66, C-134, C-131
NG
NG
Repair
35C-13
ASC - Troubleshooting
Code No. 33 Stop lamp switch system (open circuit or
ON problem)
Probable cause
This code is output if there is a stop lamp switch ON malfunction (the stop lamp
switch remains ON continuously for 15 minutes or more).
D
D
D
Does the stop lamp switch turn on
and off normally?
NO
Check the stop lamp switch
installation.
OK
YES
Check the stop lamp switch.
(Refer to GROUP 35A - On-vehicle
Service*.)
OK
Malfunction of stop lamp switch
Malfunction of harness or connector
Malfunction of ASC-ECU
NG
NG
Repair
Replace
Check the harness between the
junction block (multipurpose fuse No.
3) and the ASC-ECU, and repair if
necessary.
Measure at ASC-ECU harness
connector C-180.
D Disconnect the connector and
measure at the harness side.
D Stop lamp switch: ON
D Voltage between terminal 31 and
body earth
OK: System voltage
NG
Check the following connectors:
C-180, C-75, C-65, C-02
OK
Check the trouble symptoms.
OK
Check the following connector:
C-180
NG
Repair
OK
Check the trouble symptoms.
NG
Replace the ASC-ECU.
NOTE
*: Refer to ’97 GALANT Workshop Manual.
NG
NG
Repair
Check the harness between the stop
lamp switch and the ASC-ECU, and
repair if necessary.
35C-14
ASC - Troubleshooting
Code No. 35 Steering sensor system (ST-1, 2, N)
Probable cause
This code is output if it is detected that there is an open circuit or short-circuit
in any one of the steering sensor ST-1, ST-2 or ST-N output circuits, or if there
is an open circuit in the steering sensor earth circuit, or if the output from any
one of the ST-1, ST-2 or ST-N terminals is lower than approximately 1 V or
higher than approximately 4.5 V.
D
D
D
Measure at ASC-ECU harness
connector C-180.
D Disconnect the connector and
measure at the harness side.
D Ignition switch: ON
D Voltage between terminals 36, 37
and 44 and body earth
OK: Changes between approx. 3.5
V and 1.5 V when steering
wheel is turned.
NG: Stays at
approx. 1.5 V or
lower without
changing
Is the voltage less than 1 V at only
some terminals?
OK
Malfunction of harness or connector
Malfunction of steering sensor
Malfunction of ASC-ECU
Check the following connector:
C-180
NG:
Changes between approx.
4.5 V or higher and
approx. 1.5 V when
steering wheel is turned;
or stays at approx. 4.5 V
or higher without changing
YES
NG
Repair
OK
Check the trouble symptoms.
NG
Replace the ASC-ECU.
Replace the steering sensor.
Check the following connectors:
C-180, C-75, C-106
NG
Repair
OK
NO
Check the trouble symptoms.
NG
Check the harness between the
steering sensor and the ASC-ECU.
NG
Repair
OK
Replace the steering sensor.
Measure at steering sensor
connector C-106.
D Disconnect the connector and
measure at the harness side.
D Ignition switch: ON
D Voltage between terminal 3 and
body earth
OK: Battery voltage
NG
Check the following connectors:
C-106, C-61, C-132, C-131
OK
NG
Check the harness between the
ignition switch (IG1) and the steering
sensor, and repair if necessary.
NG
Check the following connectors:
C-106, C-62 <L.H. drive vehicles>,
C-64 <R.H. drive vehicles>
OK
Check the trouble symptoms.
NG
OK
Check the following connectors:
C-106, C-75, C-180
NG
Repair
OK
Check the trouble symptoms.
NG
Check the harness between the
steering sensor and the ASC-ECU.
OK
Replace the steering sensor.
Repair
Check the trouble symptoms.
OK
Measure at steering sensor
connector C-106.
D Disconnect the connector and
measure at the harness side.
D Continuity between terminal 2
and body earth
OK: Continuity
NG
NG
Repair
Check the harness between the
steering sensor and body earth, and
repair if necessary.
NG
Repair
35C-15
ASC - Troubleshooting
ASC - Troubleshooting
Code No. 36 Steering sensor system (ST-N)
Probable cause
This code is output if the neutral position is still detected when the steering
wheel is turned 20_ or more in either direction due to a cause such as a
short-circuit in the steering sensor (ST-N).
D
D
D
Measure at ASC-ECU harness
connector C-180.
D Disconnect the connector and
measure at the harness side.
D Ignition switch: ON
D Continuity between terminal 44
and body earth
OK: Changes between approx.
3.5 V and 1.5 V when steering
wheel is turned
OK
Malfunction of steering sensor
Malfunction of harness or connector
Malfunction of ASC-ECU
NG
Check the following connector:
C-180
Repair
OK
Check the trouble symptoms.
NG
Replace the ASC-ECU.
NG
Check the following connectors:
C-180, C-75, C-106
NG
Repair
OK
NG
Check the trouble symptoms.
Check the harness between the
steering sensor and the ASC-ECU.
NG
Repair
OK
Replace the steering sensor.
Code No. 37 Steering sensor system (ST-1, ST-2)
Probable cause
This code is output if there is a short-circuit in the steering sensor (ST-1) or the
steering sensor (ST-2) and no steering angle signal is input when the average
speed detected by the left and right rear wheel speed sensors is 15 km/h or
more.
D
D
D
Measure at ASC-ECU harness connector C-180.
D Disconnect the connector and measure at the harness side.
D Ignition switch: ON
D Continuity between terminals 36 and 37 and body earth
OK: Changes between approx. 3.5 V and 1.5 V when steering
wheel is turned
OK
Malfunction of steering sensor
Malfunction of harness or connector
Malfunction of ASC-ECU
Check the following connector: C-180
OK
Repair
Check the trouble symptoms.
NG
NG
Check the following connectors: C-180, C-75, C-106
NG
OK
Repair
Check the trouble symptoms.
NG
Check the harness between the steering sensor and the ASC-ECU.
OK
NG
Repair
Replace the steering sensor.
NG
Replace the ASC-ECU.
35C-16
ASC - Troubleshooting
Code Nos. 41, 42, 43, 44, 45, 46, 47, 48 Solenoid valve
system
Probable cause
The ASC-ECU continually monitors the solenoid valve drive circuits. These
codes are output if the ASC-ECU judges that there is an open circuit or
short-circuit in a solenoid coil or an open circuit or short-circuit in a harness
because current is not flowing even though the solenoid valve is ON, or current
is flowing even though the solenoid valve is OFF.
D
D
D
Check the solenoid valves. (Refer to P.35C-47.)
NG
Malfunction of hydraulic unit
Malfunction of harness or connector
Malfunction of ASC-ECU
Replace the hydraulic unit.
OK
Measure at hydraulic unit connectors A-51 and valve relay connector
A-46X.
D Disconnect the connectors and measure at the harness side.
D Continuity between the following terminals.
At hydraulic unit
At valve relay
21
5
22
5
OK: Continuity
NG
OK
NG
Repair
Check the trouble symptoms.
NG
OK
Check the following connectors:
A-50, C-178, C-181
Check the following connectors: A-51, A-46X
Check the harness between the hydraulic unit and the valve relay,
and repair if necessary.
OK
Check the trouble symptoms.
NG
NG
Check the harness between the hydraulic unit (solenoid valve)
and the ASC-ECU.
Repair
OK
NG
Repair
Replace the ASC-ECU.
Code No. 51 Valve relay system (ON malfunction)
Probable cause
This code is output if the ASC-ECU judges that a relay contact is fused or that
there is a short-circuit in the valve relay drive circuit because the valve relay is
OFF but power is being supplied to the solenoid valves during the initial check
when the ignition switch is turned to ON.
D
D
D
Check the valve relay. (Refer to P.35C-48.)
OK
Check the following connectors: A-46X, C-179
OK
Check the trouble symptoms.
NG
Replace the ASC-ECU.
NG
NG
Replace
Repair
Malfunction of ABS valve relay
Malfunction of harness or connector
Malfunction of ASC-ECU
35C-17
ASC - Troubleshooting
Code No. 52 Valve relay system (OFF malfunction)
Probable cause
This code is output it the ASC-ECU judges that there is a valve relay OFF
malfunction because no voltage is being supplied to the solenoid valves when
the ignition switch is at ON and the valve relay is on.
D Malfunction of ABS valve relay
D Malfunction of harness or connector
D Malfunction of ASC-ECU
Check the valve relay.
(Refer to P.35C-48.)
NG
Replace
OK
(1) NG
Measure at valve relay connector
A-46X.
D Disconnect the connector and
measure at the harness side.
D Ignition switch: ON
(1) Voltage between terminal 1 and
body earth
OK: System voltage
(2) Voltage between terminal 4 and (2) NG
body earth
OK: System voltage
OK
Check the following connector:
A-46X
OK
NG
Check the trouble symptoms.
Check the following connectors:
<L.H. drive vehicles>
A-46X, C-12, C-113
<R.H. drive vehicles>
A-46X, A-40
OK
NG
Check the following connectors:
A-46X, C-178, C-179
OK
Check the trouble symptoms.
NG
NG
Check the trouble symptoms.
Measure at valve relay connector
A-46X and ASC-ECU connectors
C-178 and C-179.
D Disconnect the connector and
measure at the harness side.
D Continuity between the following
terminals.
OK: Continuity
At valve relay
At ASC-ECU
3
73
5
54
NG
NG
NG
Repair
Check the harness between the
ignition switch (IG2) and the valve
relay, and repair if necessary.
Repair
Check the harness between fusible
link No. 5 and the valve relay, and
repair if necessary.
Repair
Check the harness between the
valve relay and the ASC-ECU, and
repair if necessary.
OK
Check the trouble symptoms.
NG
Replace the ASC-ECU.
Code No. 53 Motor relay system (OFF malfunction)
Probable cause
This code is output if motor monitoring is off (for example, when the motor is
not operating) when the ASC-ECU gives a pump motor ON command.
D Malfunction of harness or connector
D Malfunction of motor relay
D Malfunction of ASC-ECU
Caution
Because driving the motor during actuator testing will drain the battery, start the engine and let
it run for a while after testing is finished.
35C-18
ASC - Troubleshooting
MUT-II Actuator Test
Can the motor operating sound be heard?
YES
Check the following connector: C-179
NG
OK
NO
Repair
Check the trouble symptoms.
NG
Check the harness between the motor relay and ASC-ECU motor
monitoring terminal 53.
NG
OK
Measure at ASC-ECU connector C-178.
D Disconnect the connector and measure at the harness
side.
D Connect terminal 72 to earth
OK: Motor operates
NG
Measure at motor relay connector A-53X.
D Disconnect the connector and measure at the harness side.
D Voltage between terminal 5 and body earth.
OK: System voltage
OK
NG
Repair
Replace the ASC-ECU.
Check the following connectors: <L.H. drive vehicles> A-53X,
C-12, C-113, <R.H. drive vehicles> A-53X, A-40
NG
OK
Repair
OK
Check the trouble symptoms.
NG
Check the harness between fusible link No. 5 and the motor relay,
and repair if necessary.
Measure at motor relay connector A-53X.
D Disconnect the connector and measure at the harness side.
D Continuity between terminal 1 and body earth.
OK: Continuity
NG
Check the following connector: A-53X
OK
NG
Repair
OK
Check the trouble symptoms.
NG
Check the harness between the motor relay and body earth, and
repair if necessary.
Measure at motor relay connector A-53X.
D Disconnect the connector and measure at the harness side.
D Continuity between terminal 2 and body earth.
OK: Continuity
NG
Check the following connectors: A-53X, C-179
OK
NG
Repair
OK
Check the trouble symptoms.
NG
Check the harness between the motor relay and the ASC-ECU.
NG
OK
Repair
Replace the motor relay.
Measure at hydraulic unit connector A-51.
D Disconnect the connector and measure at the harness side.
D Continuity between terminal 23 and body earth.
OK: Continuity
OK
NG
OK
Check the trouble symptoms.
NG
NG
Check the harness between the hydraulic unit and body earth,
and repair if necessary.
Replace the hydraulic unit.
Check the following connectors: A-51, A-53X
OK
Check the trouble symptoms.
NG
Repair
Check motor operation. (Refer to P.35C-47.)
OK
Check the following connector: A-51
NG
NG
Repair
Check the harness between the motor relay and the hydraulic
unit, and repair if necessary.
ASC - Troubleshooting
Code No. 54 Motor relay system (ON malfunction)
Probable cause
This code is output if the ASC-ECU judges that there is a motor relay ON
malfunction when motor monitoring is on when the ASC-ECU gives a pump
motor OFF command.
D
D
D
35C-19
Malfunction of harness or connector
Malfunction of motor relay
Malfunction of ASC-ECU
Caution
(1) If a motor relay ON malfunction occurs, the motor will continue operating even when the ignition
switch is turned to OFF. If this happens, fusible link No. 5 (60 A) should be removed or hydraulic
unit connector A-51 should be disconnected immediately. Excessive running of the motor will
drain the battery.
(2) The motor relay may become hot while the motor is running or immediately after it has been
running, so take care when handling the motor relay.
Does the motor stop running when the ignition switch is
turned to OFF?
YES
Replace the ASC-ECU.
NO
Check the harness between the motor relay and the hydraulic
unit, and between the motor relay and the ASC-ECU.
OK
Replace the motor relay.
NG
Repair
35C-20
ASC - Troubleshooting
Code No. 61 Communication system between the A/T-ECU
and the ASC-ECU
Probable cause
This diagnosis code is output if an error is detected in the communication because
of an open or short circuit in the serial communication circuit between the ASC-ECU
and the A/T-ECU, a internal malfunction of the ECU or a improper shield wire.
This code is also output when diagnosis code No.76 is output. Diagnosis code No.76
indicates that the communication with the A/T-ECU is suspended due to an error
in the communication line between the ASC-ECU and the engine-ECU.
D
D
D
D
YES
MUT-II Self-Diag code
Is diagnosis code No. 76 output?
Malfunction
Malfunction
Malfunction
Malfunction
of
of
of
of
harness or connector
ASC-ECU
A/T-ECU
engine-ECU
Code No. 76 Communication system with engine-ECU (Refer
to P.35C-26.)
NO
NG
Check the following connectors:
C-30, C-51, C-181
Repair
OK
Check trouble symptom.
NG
Check the harness wire between the ASC-ECU and the A/T-ECU.
NG
Repair
OK
Check the ASC-ECU power supply circuit.
[Refer to the troubleshooting procedure for code No. 16 (Refer
to P.35C-10.)]
NG
Repair
OK
Replace the ASC-ECU.
NG
Check trouble symptom.
Replace the A/T-ECU.
Code No. 63 ECU failure
Probable cause
This code is output if a malfunction occurs in the CPU inside the ASC-ECU.
D
Replace the ASC-ECU.
Malfunction of ASC-ECU
35C-21
ASC - Troubleshooting
Code No. 65 APS or TPS circuit system
Probable cause
This diagnosis code is output if the APS opening angle is 20_ or greater than the
TPS opening angle because of a short in the APS, an open circuit in the TPS or
sticking of the vacuum actuator. As this detection condition can be applicable during
throttle control, trouble diagnosis is invalid at this time.
D
D
D
D
D
D
MUT-II Data list
65 TPS output open and close
the throttle lever.
OK: Changes smoothly between 300 mV - 5,500
mV
NG
Check the APS.
(Refer to GROUP13A - Onvehicle Service.)*
OK
Malfunction
Malfunction
Malfunction
Malfunction
Malfunction
Malfunction
NG
NG
NG
Check the harness between
the APS and the ASC-ECU,
and repair if necessary.
Repair
NG
Repair
OK
Replace the ASC-ECU.
Check the following con- NG
nectors:
B-07, C-167
Check the TPS.
NG
(Refer to GROUP 13A - Onvehicle Service.)*
Repair
OK
Check trouble symptom.
OK
NG
Check the harness between NG
the TPS and theNG
engine-ECU,
and repair if necessary.
OK
Repair
Replace the engine-ECU.
OK
NG
Check the following con- NG
nector:
B-07, C-166
OK
Check trouble symptom.
OK
NG
Repair
OK
Check trouble symptom.
Repair
Check trouble symptom.
Repair
Measure the voltage at TPS
connector B-07.
D Ignition switch: ON
the
TPS NG
D Disconnect
connector and measure at
the harness side.
D Between terminal 4 and
body earth
OK: 4.8 - 5.2 V
Check the following connector:
C-166
NG
OK
OK
Measure the voltage at engine-ECU connector C-166.
D Ignition switch: ON
D Connect the engine-ECU
connector.
D Between terminal 78 and
body earth.
Move the accelerator lever
OK: 0.3- 1.0 V (Set to idle
position)
4.5- 5.5 V (Fully open)
APS
TPS
ASC-ECU
engine-ECU
harness or connector
vacuum actuator
Check the following connectors:
B-41, C-51, C-180
NG
Vacuum actuator operation
inspection (Refer to
GROUP13A - On-vehicle
Service.)*
of
of
of
of
of
of
NG
Replace the engine-ECU.
NOTE
*:
Refer to ’97 GALANT Workshop Manual.
NG
Repair
Check the harness between
the TPS and the engine-ECU,
and repair if necessary.
Repair
35C-22
ASC - Troubleshooting
Code No. 66 TPS or APS circuit system
Probable cause
This diagnosis code is output if the TPS opening angle is 20_ or greater than the
APS opening angle because of a short in the TPS or an open circuit in the APS.
If there is an open circuit in the APS, diagnosis code No. 67 is output at the same
time. Accordingly, if only diagnosis code No. 67 is output, the cause is probably an
abnormality in the TPS circuit system.
D
D
D
D
MUT-II Self-Diag code
Is diagnosis code No. 67 output?
YES
Malfunction
Malfunction
Malfunction
Malfunction
of
of
of
of
APS
TPS
harness or connector
engine-ECU
Code No. 67 APS circuit system
(Refer to P.35C-7.)
NO
Check the TPS.
(Refer to GROUP 13A - On-vehicle Service.)*
NG
Repair
OK
Measure the voltage at engine-ECU connector C-166.
D Ignition switch: ON
D Connect the engine-ECU connector.
D Between terminals 78 and body earth
D Move the accelerator lever.
OK: 0.3 - 1.0 V (Set to idle position)
4.5 - 5.5 V (Fully open)
NG
NG
Check the following connectors:
B-07, C-166
OK
Check trouble symptom.
NG
OK
Check the harness between the TPS and the engineECU, and repair if necessary.
Check the following connector:
C-166
OK
Check trouble symptom.
NG
NG
Repair
NOTE
*:
Refer to ’97 GALANT Workshop Manual.
Replace the engine-ECU.
Repair
35C-23
ASC - Troubleshooting
Code No. 67 APS circuit system
Probable cause
This diagnosis code is output if the APS output voltage is less than 0.2 V due to
an open circuit or other malfunction in the APS circuit. The APS power supply and
earth are supplied from the engine-ECU, and the output signal is used by the A/T-ECU
and auto-cruise control-ECU as well as by the ASC-ECU.
D
D
D
D
MUT-II Data list
67 APS output Open and
close the throttle lever.
OK: Changes smoothly between 300 mV - 5,500
mV
NG
OK
Check the following connector:
C-180
OK
Check trouble symptom.
NG
Measure the voltage at APS
connector B-41.
D Ignition switch: ON
the APS
D Disconnect
connector and measure at
the harness side.
D Measure at the harness
side.
D Between terminal 1 and
body earth
OK: 4.8 - 5.2 V
NG
of
of
of
of
APS
ASC-ECU
engine-ECU
harness or connector
Check the following connectors:
B-41, C-167
NG
Repair
OK
Check trouble symptom.
NG
Check the harness between
the TPS and the engine-ECU,
and repair if necessary.
OK
NG
Repair
OK
Repair
Replace the engine-ECU.
Check the APS.
(Refer to GROUP 13A - Onvehicle Service.)*
NG
Repair
OK
NG
Replace the ASC-ECU.
Malfunction
Malfunction
Malfunction
Malfunction
Measure the voltage at ASCECU connector C-180.
D Ignition switch: ON
D Disconnect the ASC-ECU
connector and measure at
the harness side.
D Between terminal 39 and
body earth
OK: 0.3 V or more
NG
OK
Check trouble symptom.
NG
Check the harness between
the APS and the ASC-ECU,
and repair if necessary.
OK
Check the following connector:
C-180
OK
Check trouble symptom.
NG
Replace the ASC-ECU.
Check the following connectors:
B-41, C-51, C-180
NG
Repair
NG
Repair
35C-24
ASC - Troubleshooting
Code No. 71 Lateral G sensor circuit system
Probable cause
This code is output at the following times.
D If the G sensor output is less than 0.5 V or more than 4.5 V.
D If there is an open circuit or short-circuit in a G sensor system harness.
D Malfunction of G sensor
D Malfunction of harness or connector
D Malfunction of ASC-ECU
Check the lateral G sensor.
(Refer to P.35C-53.)
NG
Replace
OK
Measure at ASC-ECU connector
C-181.
D Connector connected
D Ignition switch: ON
D Between terminal 8 and body
earth
OK: 2.4 - 2.6 V
NG
Check the following connectors:
C-181, C-51, C-170
OK
NG
NG
Check the trouble symptoms.
Repair
Check the harness between the
lateral G sensor and the ASC-ECU,
and repair if necessary.
OK
Check the following connector:
C-181
NG
Repair
OK
Check the trouble symptoms.
NG
Replace the ASC-ECU.
Code No. 72 Yaw rate sensor circuit system (open or
short-circuit)
Probable cause
This code is output at the following times.
D If the yaw rate sensor output is less than 0.3 V or more than 4.7 V.
D If there is an open circuit or short-circuit in a yaw rate sensor system
harness.
D Malfunction of yaw rate sensor
D Malfunction of harness or connector
D Malfunction of ASC-ECU
Check the yaw rate sensor.
(Refer to P.35C-53.)
NG
Replace
OK
Measure at ASC-ECU connector
C-181.
D Connector connected
D Ignition switch: ON
D Voltage between terminal 10 and
body earth
OK: 2.4 - 2.6 V
NG
Check the following connectors:
C-181, C-51, C-169
OK
Check the trouble symptoms.
OK
Check the following connector:
C-181
NG
Repair
OK
Check the trouble symptoms.
NG
Replace the ASC-ECU.
NG
NG
Repair
Check the harness between the
yaw rate sensor and the ASC-ECU,
and repair if necessary.
35C-25
ASC - Troubleshooting
Code No. 73 Master cylinder pressure sensor system
Probable cause
This code is output at the following times.
D If there is an open circuit or short-circuit in a master cylinder pressure
sensor system harness and the sensor output is less than 0.3 V or more
than 4.7 V.
D If the master cylinder pressure sensor and the stop lamp switch conditions
are not identical.
D Malfunction of master cylinder pressure sensor
D Malfunction of harness or connector
D Malfunction of ASC-ECU
Check the stop lamp switch.
(Refer to GROUP 35A - On-vehicle
Service*.)
NG
Replace
OK
Check the master cylinder pressure
sensor. (Refer to P.35C-46.)
NG
Replace
OK
Measure at ASC-ECU connector
C-181.
D Connector connected
D Ignition switch: ON
D Voltage between terminal 24 and
body earth
OK: 0.4 - 4.5 V
NG
Check the following connectors:
C-181, C-75, C-115
<L.H. drive vehicles>, C-113
<R.H. drive vehicles>, A-47
OK
Check the trouble symptoms.
NG
NG
OK
Check the following connector:
C-181
NG
Repair
Check the harness between the
master cylinder sensor and the
ASC-ECU, and repair if necessary.
Repair
OK
NG
Check the trouble symptoms.
Replace the ASC-ECU.
NOTE
*: Refer to ’97 GALANT Workshop Manual.
Code No. 74 Yaw rate sensor or lateral G sensor system
Probable cause
This code is output if an open circuit cannot be confirmed, but the difference
between the actual yaw rate value and the target yaw rate (the value calculated
from the lateral G sensor value and the vehicle speed) is 5_ or more when the
vehicle speed is 40 km/h or higher.
D Malfunction of yaw rate sensor
D Malfunction of lateral G sensor
D Malfunction of ASC-ECU
Is MUT-II diagnosis code No. 71 being output?
YES
NO
Check the yaw rate sensor. (Refer to P.35C-53.)
NG
Code No. 71 Lateral G sensor circuit system.
(Refer to P.35C-24.)
Replace
OK
Check the following connectors: C-181, C-51, C-169
NG
Repair
OK
Check the trouble symptoms.
NG
Replace the ASC-ECU.
35C-26
ASC - Troubleshooting
Probable cause
Code No. 75 Engine-ECU system
Code No. 77 TCL vacuum or ventilation solenoid valve
system
These codes are output when the engine-ECU detects a system abnormality. (MPI
system abnormalities are transmitted from the engine-ECU to the ASC-ECU by serial
communication.)
D
Malfunction of MPI system
Carry out MPI system troubleshooting. (Refer to GROUP 13A Troubleshooting.)*
NOTE
*:
Refer to ’97 GALANT Workshop Manual.
Code No. 76 Communication system with engine-ECU
Probable cause
This diagnosis code is output if an error is detected in the communication contents
because of an open or short circuit in the serial communication circuit between the
ASC-ECU and the engine-ECU, a malfunction of ECU and a defective shielding of
the shied wire.
D
D
D
NG
Check the following connectors:
C-181, C-51, C-166
Malfunction of harness or connector
Malfunction of ASC-ECU
Malfunction of engine-ECU
Repair
OK
Check trouble symptom.
NG
Inspect the harness between the ASC-ECU and the engine-ECU.
NG
Repair
OK
Check the ASC-ECU power supply circuit.
[Refer to the troubleshooting procedure for code No.16 (P.35C-10.)]
NG
Repair
OK
Replace the ASC-ECU.
Check trouble symptom.
NG
Replace the engine-ECU.
35C-27
ASC - Troubleshooting
Code No. 78 Accumulator stroke switch system
Probable cause
This code is output at the following times.
D If the accumulator signal being is output continuously (open circuit or
short-circuit in accumulator stroke switch circuit or incorrect accumulator
pressure)
D If the accumulator stroke switch does not turn from on to off during the initial
check even though the diagonal accumulator valve is on (incorrect pressure
reduction)
D If the accumulator stroke switch turns from on to off within 1 minute after
pressure accumulation is complete (fluid leak)
D
D
D
D
MUT-II Actuator Test
(1) 17 Accumulator pressure
reduction
OK: Accumulator stroke switch
changes from on to off
(2) 16 Accumulator pressure hold
OK: Accumulator stroke switch
changes from off to on
OK
MUT-II Data list
D Carry out 1 minute after actuator
test No. 16 is completed.
D No. 77, 78 Accumulator stroke
switch
OK: ON is displayed
NG
Check the following connectors:
A-49, C-181
OK
Check the trouble symptoms.
NG
NG
NG
Replace the hydraulic unit.
NG
Repair
Check the harness between the
accumulator stroke switch and the
ASC-ECU.
OK
Repair
NG
Repair
OK
Check the trouble symptoms.
accumulator stroke switch
harness or connector
hydraulic unit
ASC-ECU
Replace the ASC-ECU.
NG
OK
Check the following connectors:
A-49, C-178
of
of
of
of
OK
NG
Measure at hydraulic unit connector
A-49.
D Ignition switch: ON
D Voltage between terminal 33 and
body earth
OK: 4.5 - 5.5 V
Malfunction
Malfunction
Malfunction
Malfunction
Replace the ASC-ECU.
Check the harness between the
accumulator stroke switch and the
ASC-ECU.
OK
Replace the hydraulic unit.
NG
Repair
35C-28
ASC - Troubleshooting
INSPECTION CHART FOR TROUBLE SYMPTOMS
Trouble symptom
Communication is not possible between the MUT-II and all other
systems.
Communication is not possible between the MUT-II and the ASC-ECU.
The ASC/TCL operation lamp does not turn
The ASC/TCL operaon when the ignition switch is turned to ON.
tion lamp display does
not operate correctly.
The ASC/TCL operation lamp stays on after
the engine has been started.
The ASC-OFF indication lamp does not turn
The ASC-OFF indicaon when the ignition switch is turned to ON.
tion lamp display does
not operate correctly.
The ASC-OFF indication lamp stays on
after the engine has been started.
The ASC-OFF indication lamp does not turn
on even if the ASC switch is continuously
pressed to the OFF side while the engine is
idling.
The ABS warning lamp does not turn on
The ABS warning lamp
when the ignition switch is turned to ON.
display does not operate correctly.
The ABS warning lamp stays on after the
engine has been started.
The ABS warning lamp does not turn on
when the ignition switch is turned to START.
The brakes do not operate correctly.
Malfunction of TCL
ASC/TCL operation lamp illuminates in the
operation
TCL operation range, but torque is not
reduced.
Poor starting
Engine output is reduced in the TCL
non-operation range (ASC/TCL operation
Poor acceleration
lamp does not illuminate) and starting and
acceleration performance is poor.
Inspection procedure No.
1
Reference page
2
3
35C-30
35C-31
4
35C-31
5
35C-32
6
35C-32
7
35C-33
8
35C-34
9
35C-35
10
35C-35
11
12
35C-36
35C-36
35C-29
Caution
(1) The brake operation feeling changes (kickback conditions) during ASC operation in the same
way as it changes during ABS operation. This happens because hydraulic pressure for certain
wheels is being forced to increase or decrease, causing intermittent changes in the brake
line pressure, and is not a sign of a problem.
(2) The ASC system does not operate while the brake warning lights are on (such as if the brake
fluid level is low or the parking brake has been applied).
35C-29
ASC - Troubleshooting
INSPECTION PROCEDURE FOR TROUBLE SYMPTOMS
Inspection procedure 1
Communication is not possible between the MUT-II and
all other systems.
Probable cause
The cause is probably a malfunction of the power supply circuit or earth circuit
for the diagnosis connector.
D Malfunction of diagnosis connector
D Malfunction of harness or connector
Measure at diagnosis connector
C-20.
D Voltage between terminal 16 and
body earth
OK: System voltage
NG
Check the following connectors:
<L.H. drive vehicles>
C-20, C-66, C-63, C-132, C-141
<R.H. drive vehicles>
C-20, C-66, C-62, C-14
OK
OK
Check the trouble symptoms.
Measure at diagnosis connector
C-20.
D Continuity between terminals 4
and 5 and body earth
OK: Continuity
OK
Check the trouble symptoms.
NG
Replace the MUT-II.
NG
Check the following connector:
C-20
OK
Check the trouble symptoms.
NG
NG
NG
NG
Repair
Check the harness between the
power supply and the diagnosis
connector, and repair if necessary.
Repair
Check the harness between the
diagnosis connector and earth, and
repair if necessary.
35C-30
ASC - Troubleshooting
Inspection procedure 2
Communication is not possible between the MUT-II and
the ASC-ECU.
Probable cause
The cause is probably an open circuit in the ASC-ECU power supply circuit or
an open circuit in the diagnosis output circuit.
D Blown fuse
D Malfunction of harness or connector
D Malfunction of ABS-ECU
Measure at diagnosis connector C-20
and ASC-ECU connector C-179.
D Disconnect the connectors and
measure at the harness side.
D Continuity between the following
terminals.
At diagnosis
connector
At ASC-ECU
1
58
7
52
OK: Continuity
NG
Check the following connectors:
C-20, C-66, C-83, C-49, C-51, C-179
OK
Check the trouble symptoms.
NG
NG
Repair
Check the harness between the
ASC-ECU and the diagnosis
connector, and repair if necessary.
OK
Measure at ASC-ECU connector
C-178.
D Disconnect the connector and
measure at the harness side.
D Ignition switch: ON
D Voltage between terminal 71 and
body earth
OK: System voltage
NG
Check the following connectors:
C-178, C-75, C-66 <L.H. drive
vehicles>, C-134, C-131
OK
Check the trouble symptoms.
NG
NG
Repair
Check the harness between the
ignition switch (IG2) and the
ASC-ECU, and repair if necessary.
OK
Measure at ASC-ECU connectors
C-178 and C-181.
D Disconnect the connectors and
measure at the harness side.
D Continuity between terminals 13,
25, 26 and 82 and body earth
OK: Continuity
NG
Check the following connectors:
C-178, C-181
OK
Check the trouble symptoms.
NG
NG
Repair
Check the harness between the
ASC-ECU and earth, and repair if
necessary.
OK
Check the following connectors:
C-178, C-181
NG
Repair
OK
Check the trouble symptoms.
NG
Replace the ASC-ECU.
35C-31
ASC - Troubleshooting
Inspection procedure 3
The ASC/TCL operation lamp does not turn on when the
ignition switch is turned to ON.
Probable cause
The cause is usually an open circuit in the indicator circuit because of
something such as a blown bulb.
D Malfunction of harness or connector
D Malfunction of ASC-ECU
D Malfunction of indicator bulb
Do other indicator lamps illuminate
when the ignition switch is turned to
ON?
NG
Check the following connectors:
C-131, C-135, D-03
OK
OK
NG
NG
Check the trouble symptoms.
Check the following connectors:
D-03, C-50, C-179
NG
OK
Repair
Check the harness between the
ignition switch (IG1) and the
combination meter, and repair if
necessary.
Repair
Check the trouble symptoms.
NG
Check the harness between the
combination meter and the
ASC-ECU.
NG
Repair
OK
Check for a blown bulb.
NG
OK
Replace the ABS/TCL operation lamp
bulb.
Replace the ASC-ECU.
Inspection procedure 4
The ASC/TCL operation lamp stays on after the engine
has been started.
Probable cause
The cause is probably a short-circuit in the ASC/TCL operation lamp illumination
circuit.
D Malfunction of harness or connector
D Malfunction of ASC-ECU
Dose the ASC/TCL operation lamp
switch off when ASC-ECU connector
C-179 is disconnected?
YES
Replace the ASC-ECU.
NO
Check the following connectors:
D-01, C-50, C-179
NG
Repair
OK
Check the trouble symptoms.
Check the harness between the
combination meter and the
ASC-ECU, and repair if necessary.
35C-32
ASC - Troubleshooting
Inspection Procedure 5
The ASC-OFF indication lamp does not turn on when the
ignition switch is turned to ON.
Probable cause
The main cause is an open circuit in the indicator circuit because of a burnt-out
indicator lamp bulb.
D
D
D
Do other warning lamps illuminate when
the ignition switch is at ON position?
NO
Check the following connectors:
C-131, C-135, D-03
Malfunction of harness or connector
Malfunction of ASC-ECU
Malfunction of indicator lamp bulb
OK
NG
NG
YES
Check the harness between the combination meter and the junction block,
and repair if necessary.
Repair
Check the following connectors:
D-03, C-50, C-179
NG
Check trouble symptom.
Repair
OK
Check trouble symptom.
NG
Inspect the harness between the combination meter and the ASC-ECU.
OK
Check if a ASC-OFF indicator lamp bulb
is burnt out.
NG
NG
Repair
Replace the lamp bulb.
OK
Replace the ASC-ECU.
Inspection Procedure 6
ASC-OFF indicator lamp stays on after the engine has
been started.
Probable cause
The ASC-OFF indication lamp also serve as a system warning lamp. This indication
lamp illuminates when threre is a problem with the system.
D
D
Is communication with the MUT-II possible?
YES
Are the diagnosis codes normal?
NO
NO
YES
Does the ASC-OFF indicator lamp
switch off when ASC-ECU connector
C-179 is disconnected?
NO
Check the following connectors:
D-01, C-50, C-179
NG
Repair
YES
OK
Other system related to the ASC
Malfunction of harness or connector
Inspection procedures for each trouble
symptom (Refer to P.35C-28.)
Chart classified by diagnosis codes
(Refer to P.35C-6.)
Replace the ASC-ECU.
Check trouble symptom.
NG
Check the harness between the combination meter and the ASC-ECU, and
repair if necessary.
35C-33
ASC - Troubleshooting
Inspection Procedure 7
The ASC-OFF indication lamp does not turn on even if the
ASC switch is continuously pressed to the OFF side while
the engine is idling.
Probable cause
If the indicator lamp does not illuminate when the switch is operated, there is a
malfunction in the switch, switch circuit or in the ASC-ECU.
D
D
D
MUT-II Data list
D 44 ASC OFF switch
D Press the ASC switch continuously
to the OFF side while the engine
is idling.
OK: ON is displayed
OK
Malfunction of harness or connector
Malfunction of ASC switch
Malfunction of ASC-ECU
Replace the ASC-ECU.
NG
Check the following connectors:
C-178, C-75, C-98, C-62 <L.H. drive
vehicles>, C-64 <R.H. drive vehicles>
NG
Repair
OK
Check trouble symptom
NG
Inspect the harnesses between the
ASC-ECU and the ASC switch, and between the ASC switch and the body
earth.
OK
ASC switch component inspection (Refer to P.35C-54.)
OK
Repair
35C-34
ASC - Troubleshooting
Inspection procedure 8
The ABS warning lamp does not turn on when the
ignition switch is turned to ON (engine stopped).
Probable cause
When power is being supplied to the ASC power supply, the valve relay
changes from OFF to ON, OFF and ON again as part of the initial check.
Because of this, the ABS warning lamp illuminates twice when the valve relay is
off, even if there is a problem in the circuit between the ABS warning lamp and
the ASC-ECU.
Accordingly, if the lamp does not illuminate, the cause may be an open circuit
in the lamp power supply circuit, a blown lamp bulb, or an open circuit in the
circuits between the ABS warning lamp and the ASC-ECU or between the ABS
warning lamp and the valve relay.
D Blown fuse
D Blown ABS warning lamp bulb
D Malfunction of harness or connector
Check the following fuse:
Multipurpose fuse No. 13
NG
OK
Measure at connector D-03.
D Disconnect the connector and
measure at the harness side.
D Ignition switch: ON
D Voltage between terminal 4 and
body earth
OK: System voltage
NG
Refer to GROUP 00 - Inspection
Procedures when there is a Blown
Fuse*.
Check the following connectors:
D-03, C-135, C-131
OK
Check the trouble symptoms.
NG
NG
OK
Measure at connector D-01.
D Disconnect the connector and
measure at the combination
meter side.
D Ignition switch: ON
D Warning lamp when terminal 44
is shorted to body earth
OK: Illuminates
NG
Check the following connectors:
D-01, D-03
OK
Check the trouble symptoms.
NG
Repair
OK
Check the trouble symptoms.
NG
OK
OK
Check the following connectors
and diode:
D-01, C-50, C-179, C-158, A-46X
Check for a blown bulb.
NG
Check the harness between the ABS
warning lamp and the ASC-ECU,
and between the ABS warning lamp
and the valve relay, and repair if
necessary.
NOTE
*: Refer to ’97 GALANT Workshop Manual.
NG
NG
Repair
Check the harness between the
ignition switch (IG1) and the ABS
warning lamp, and repair if
necessary.
Replace the ABS warning lamp
bulb.
Repair
Replace the combination meter.
35C-35
ASC - Troubleshooting
Inspection procedure 9
The ABS warning lamp stays on after the engine has
been started.
Probable cause
The cause is probably a short-circuit in the ABS warning lamp illumination circuit.
D Malfunction of combination meter
D Malfunction of ASC-ECU
D Malfunction of harness (short-circuit)
NOTE
This trouble symptom is limited to cases where communication with the MUT-II is possible (ASC-ECU power
supply is normal) and a normal diagnosis code is output.
Does the ABS warning lamp remain illuminated when
combination meter connector D-01 is disconnected and the
ignition switch is at ON?
YES
Replace the combination meter.
NO
D
D
D
D
YES
Disconnect ASC-ECU connector C-179.
Disconnect valve relay connector A-46X.
Ignition switch: ON
Does the ABS warning lamp switch off?
Replace the ASC-ECU.
NO
Check the harness between the ABS warning lamp and the ASCECU, and between the ABS warning lamp and the valve relay,
and repair if necessary.
Inspection procedure 10
The ABS warning lamp does not turn on when the
ignition switch is turned to START.
Probable cause
The ASC-ECU uses the IG2 power supply which is turned off when the ignition
switch is at the START position. The ABS warning lamp uses the IG1 power
supply which is not turned off when the ignition switch is at the START position.
Thus the problem is with the lamp illumination circuit at the valve relay side.
D Malfunction of valve relay
D Malfunction of harness or connector
Check the valve relay.
(Refer to P.35C-48.)
NG
Replace the valve relay.
OK
Measure at valve relay connector
A-46X.
D Disconnect the connector and
measure at the harness side.
D Disconnect ASC-ECU connector
C-179.
D Ignition switch: ON
D Measure at the harness side of
valve relay connector A-46X.
OK: System voltage
NG
Check the following connector and
diode:
A-46X, C-158
OK
Check the trouble symptoms.
OK
Check the following connector:
A-46X
NG
Repair
OK
Check the trouble symptoms.
NG
Check the harness between the
valve relay and earth, and repair if
necessary.
NG
NG
Repair
Check the harness between the
combination meter and the valve
relay, and repair if necessary.
35C-36
ASC - Troubleshooting
Inspection procedure 11
The brakes do not operate correctly.
Probable cause
The brake operating feel can change according to the driving conditions and
road surface conditions, so it is difficult to judge that there is a problem, but if
there is no diagnosis code output, carry out the following inspection.
D
D
D
D
D
D
D
Check the hydraulic unit.
(Refer to GROUP 35B - On-vehicle Service*.)
OK
Incorrect speed sensor installation
Malfunction of harness or connector
Malfunction of ABS rotor
Foreign material sticking to speed sensor
Malfunction of wheel bearing
Malfunction of hydraulic unit
Malfunction of ASC-ECU
Check the speed sensor circuit system. [Refer to inspection
procedures for diagnosis code No. 11 - 14 output (P.35C-8).]
NG
Repair
NOTE
*: Refer to ’97 GALANT Workshop Manual.
Inspection Procedure 12
ASC/TCL operation lamp illuminates in the TCL operation
range, but torque is not reduced.
Engine output is reduced in the TCL non-operation range
(ASC/TCL operation lamp does not illuminate) and
starting and acceleration performance is poor.
Probable cause
In cases such as the above, the electrical system is normal, and the cause is probably
an abnormality in the mechanical system (vacuum actuator).
D
D
D
D
D
D
D
Malfunction of vacuum solenoid valve
Malfunction of ventilation solenoid valve
Malfunction of vacuum actuator
Incorrect vacuum hose connector
Malfunction of throttle link
Malfunction of vacuum tank
Blocked air cleaner element
As the cause is probably a malfunction of the vacuum actuator system, carry out inspection of the following items
in order.
D Vacuum solenoid valve operation inspection (Refer to GROUP 13A - On-vehicle Service.)*
D Ventilation solenoid valve operation inspection (Refer to GROUP 13A - On-vehicle Service.)*
D Disconnected or mis-connected vacuum hose inspection (Refer to GROUP 13A - On-vehicle Service.)*
D Throttle link operation inspection (Refer to GROUP 13A - On-vehicle Service.)*
D Vacuum tank inspection (Refer to GROUP 13A - On-vehicle Service.)*
D Air cleaner element blockage inspection
NOTE
*: Refer to ’97 GALANT Workshop Manual.
35C-37
ASC - Troubleshooting
DATA LIST REFERENCE TABLE
The following ECU input data can be read by the MUT-II.
No.
Inspection item
Inspection contents
Normal condition
11
FR wheel speed
Actual driving
12
FL wheel speed
Speedometer display and
MUT-II display are the
same
13
RR wheel speed
14
RL wheel speed
17
Engine speed
Engine: Idling
Tachometer display and
MUT-II display are the
same
18
ASC-ECU power supply
and voltage
Ignition switch: ON
9 - 16 V
20
Lateral G sensor
Vehicle stopped
2.4 - 2.6 V
Actual driving
Display value increases
and decreases around
2.5 V
Vehicle stopped
2.4 - 2.6 V
21
Yaw rate sensor
Actual driving
22
24
Steering angle
Steering wheel position
Turning to the right
2.4 - 4.7 V
Turning to the left
0.3 - 2.6 V
Turned 90_ to the right
+90_
Turned 90_ to the left
- 90_
Fully closed
Approx. 0.5 V
Depressed
Increases to max. 4.5 V
from the above value
Master cylinder pressure
sensor
Brake pedal position
28
Engine type
Ignition switch: ON
6A13
29
Engine specification 3
Ignition switch: ON
Normal
30
Engine specification 2
Ignition switch: ON
N/A
31
Engine specification 1
Ignition switch: ON
SOHC
32
Destination
Ignition switch: ON
EC
36
Stop lamp switch
Brake pedal position
41
Steering sensor (ST-N)
Steering wheel position
Engine started
Depressed
ON
Released
OFF
Neutral position
Turned 90_ from neutral
position
ON
OFF
42
Steering sensor (ST-1)
Steering wheel position: Turned slowly to the left
Display alternates
tween OFF and ON
be-
43
Steering sensor (ST-2)
Steering wheel position: Turned slowly to the right
Display alternates
tween OFF and ON
be-
35C-38
ASC - Troubleshooting
No.
Inspection item
Inspection contents
44
ASC-OFF switch
ASC-OFF switch operation
Pressed
ON
Released
OFF
ASC-ON switch operation
Pressed
ON
Released
OFF
ASC switch: ON
Driving on low i road
ASC/TCL
lamp ON
operation
ON
ASC/TCL
lamp OFF
operation
OFF
45
46
65
67
74
75
76
77
78
ASC-ON switch
Slip control
TPS system
APS system
Trace control
Idle switch
Ignition switch
Normal condition
Accelerator pedal position
Ignition switch: ON
Selector lever position:
P
Fully closed
300 - 1000 mV
Depressed
Gradually increases from
above value
Fully open
4500 - 5500 mV
Accelerator pedal position
Ignition switch: ON
Selector lever position:
P
Fully closed
300 - 1000 mV
Depressed
Gradually increases from
above value
Fully open
4500 - 5500 mV
ASC switch: ON
Driving on low i road
ASC/TCL
lamp ON
operation
ON
ASC/TCL
lamp OFF
operation
OFF
Accelerator pedal position
Fully closed
ON
Fully open
OFF
Ignition switch position
ON
ON
OFF
OFF
Accumulator stroke switch
(FR - RL)
Accumulator pressure (FR - RL) Held
ON
Accumulator pressure (FR - RL) Released
OFF
Accumulator stroke switch
(FL - RR)
Accumulator pressure (FL - RR) Held
ON
Accumulator pressure (FL - RR) Released
OFF
NOTE
The pressure inside the accumulators can be held and released by carrying out actuator tests. (Refer
to P.35C-39.)
35C-39
ASC - Troubleshooting
ACTUATOR TEST REFERENCE TABLE
The MUT-II can be used to force-drive components in order to carry out the following actuator tests.
Item Nos. 01 - 04 (ABS solenoid valves)
Drive pattern
ON
Pump OFF
motor Pressure
increase
ABS
solenoid
valve
Pressure
hold
Pressure
decrease
1s
2s
Item Nos. 05 - 08 (ASC solenoid valves)
Drive pattern
ON
Pump
OFF
motor
ASC
ON
solenoid
OFF
valve
ABS sole- ON
noid valve
OFF
(IN)
(Brake pressure
for applicable
wheel)
1s
Actuator test specifications
Item
No.
Inspection item
01
ABS solenoid valve
(front-right) control
02
ABS solenoid valve
(front-left) control
03
ABS solenoid valve
(rear-right) control
04
ABS solenoid valve
(rear-left) control
05
ASC solenoid valve
(front-right) control
*4
06
ASC solenoid valve
(front-left) control *4
07
ASC solenoid valve
(rear-right) control
*4
08
ASC solenoid valve
(rear-left) control *4
09
TCL throttle
2s
(Pressure (Pressure increase)
hold)
Details
*1
Drives the ABS solenoid
valves and pump motor for
each channel in the hydraulic unit.
*2
Drives the ASC solenoid
valves, ABS solenoid valves
and the pump motor.
The wheel which is diagonally opposite the wheel
being driven (example: the
rear-left wheel when the
front-right wheel is being
driven) is set to holding
mode.
*3
A torque request 0 signal
and a fully-close instruction
are sent to the engine-ECU
for 3 seconds. Furthermore,
service data item No. 65
APS and No. 67 TPS are
displayed at the same time.
35C-40
ASC - Troubleshooting
Item No. 16 (Accumulator pressure
holding) Drive pattern
Pump
motor
ASC diagonal cut
solenoid
valve
ABS
solenoid
valve (IN)
ON
OFF
ON
OFF
Item
No.
Inspection Item
12
Pump motor
*1
The pump motor is driven for
approximately 2 seconds.
16
Accumulator pressure holding
*2
The ASC solenoid valves
(diagonal cut valves) and the
pump motor are driven to
that pressure builds up in the
accumulator.
Furthermore, service data
Nos. 77 and 78 (accumulator stroke switches) are
displayed at the same time.
17
Accumulator pressure reduction
ON
OFF
ON
Accumu- OFF
lator
stroke
ON
switch (2
systems) OFF
T1
Item No. 17 (Accumulator pressure
reduction) Drive pattern
ASC
ON
diagonal
accumula- OFF
tor valve ON
Accumula- OFF
tor stroke
switch (2 ON
systems) OFF
T2
Details
The ASC solenoid valves
(diagonal booster valves)
and the pump motor are
driven to that pressure is
reduced in the accumulator.
Furthermore, service data
Nos. 77 and 78 (accumulator stroke switches) are
displayed at the same time.
NOTE
*1: Actuator testing cannot be carried out if the ABS is in
fail-safe mode, or if the speed of the fast of the four
wheels is 10 km/h or more. In addition, the ABS warning
lamp will flash and all control operations will be stopped
during actuator testing.
*2: Actuator testing cannot be carried out if the ASC is in
fail-safe mode, or if the speed of the fast of the four
wheels is 10 km/h or more. In addition, the ASC/TCL
operation lamp will flash and all control operations will
be stopped during actuator testing.
*3: Actuator testing cannot be carried out if the TCL is in
fail-safe mode, or if the speed of the fast of the four
wheels is 10 km/h or more. In addition, the ASC/TCL
operation lamp will flash and all control operations will
be stopped during actuator testing.
*4: The ASC solenoid valves indicate the diagonal cut valves
and diagonal accumulator valves. Only the valves for
the applicable wheel are driven during actuator testing.
T1: Driven until the two accumulator stroke switch systems
both turn on. (Driven for a maximum of 10 seconds if
the systems do not turn on.)
T2: Driven until the two accumulator stroke switch systems
both turn off. (Driven for a maximum of 10 seconds if
the systems do no turn off.)
35C-41
ASC - Troubleshooting
CHECK AT ASC-ECU
TERMINAL VOLTAGE CHECK CHART
(1) Voltage measurements are taken between each terminal and earth.
(2) The terminal layout is shown in the diagram below.
Terminal
No.
Check item
Check condition
Normal condition
1
ABS solenoid valve OUT
(FL)
Ignition switch: ON (when initial check is
complete)
System voltage
2
ABS solenoid valve OUT
(RR)
Ignition switch: ON (when initial check is
complete)
System voltage
3
Diagonal booster valve
(FL - RR)
Ignition switch: ON (when initial check is
complete)
System voltage
5
A/T-ECU data transmission
Engine: Idling
Other than 0 V
6
Engine-ECU data transmission
Engine: Idling
Other than 0 V
8
Lateral G sensor input
Ignition switch: ON
2.4 - 2.6 V
(when horizontal)
10
Yaw rate sensor
Ignition switch: ON
2.4 - 2.6 V
(when stopped)
11
Yaw rate sensor earth
At all times
0.5 V or less
12
Master cylinder pressure sensor and accumulator stroke switch
power supply
Ignition switch: ON
4.8 - 5.2 V
13
ECU earth
At all times
1 V or less
14
ABS solenoid valve IN
(FR)
Ignition switch: ON (when initial check is
complete)
System voltage
15
ABS solenoid valve IN
(RL)
Ignition switch: ON (when initial check is
complete)
System voltage
16
Diagonal booster valve
(FL - RR)
Ignition switch: ON (when initial check is
complete)
System voltage
18
A/T-ECU data transmission
Engine: Idling
Other than 0 V
19
Engine-ECU data transmission
Engine: Idling
Other than 0 V
21
Lateral G sensor earth
At all times
0.5 V or less
23
Master cylinder pressure sensor earth
At all times
0.5 V or less
35C-42
ASC - Troubleshooting
Terminal
No.
Check item
Check condition
Normal condition
24
Master cylinder pressure sensor input
Ignition switch: ON
Brake pedal depressed
0.4 - 4.5 V
25
ECU earth
At all times
1 V or less
26
ECU earth
At all times
1 V or less
31
Stop lamp switch
Ignition switch: ON
Stop lamp switch: ON
System voltage
Stop lamp switch: OFF
1 V or less
36
Steering sensor (ST-1)
Engine: Idling Steering wheel turned slowly
Flashing
approx. 1.5
approx. 3.5 V
between
V and
37
Steering sensor (ST-2)
Engine: Idling Steering wheel turned slowly
Flashing
approx. 1.5
approx. 3.5 V
between
V and
38
ASC-ECU power supply
Ignition switch: ON
System voltage
39
APS
Ignition switch: ON
44
Steering sensor (ST-N)
Engine: Idling
Accelerator pedal: Fully closed
0.3 - 1.0 V
Accelerator pedal: Fully open
4.5 - 5.5 V
Steering wheel: Neutral position
1.3 - 2.0 V
Steering wheel: Turned
90_ from neutral position
3.0 - 4.1 V
51
ECU backup power supply
At all times
System voltage
52
Diagnosis data input/
output
When MUT-II is connected
Serial
communication
with MUT-II
When MUT-II is not connected
1 V or less
Ignition switch: ON
When motor is on
System voltage
When motor is on
1 V or less
53
Motor monitoring input
54
Valve relay monitoring
input
Ignition switch: ON
55
ABS warning lamp
Ignition switch: ON
56
58
ASC-OFF indicator
Diagnosis selection input
Ignition switch: ON
System voltage
When lamp is off
System voltage
When lamp is on
1 V or less
When lamp is off
System voltage
When lamp is on
1 V or less
When MUT-II is connected
1 V or less
When MUT-II is not connected
System voltage
35C-43
ASC - Troubleshooting
Terminal
No.
Check item
62
ASC/TCL
lamp
71
72
73
74
Check condition
operation
ASC-ECU power supply
Motor relay output
Valve relay output
Ignition switch: ON
Normal condition
When lamp is off
System voltage
When lamp is on
1 V or less
Ignition switch: ON
System voltage
Ignition switch: START
0V
Ignition switch: ON
Ignition switch: ON
When motor is on
1 V or less
When motor is off
System voltage
When relay turns on
approx. 1 second after
engine starts
1 V or less
When system problem
detection relay is OFF
System voltage
Shift lever: Reverse
System voltage
Shift lever: Other than
above
1 V or less
Backup lamp switch input <M/T>
Ignition switch: ON
78
Diagonal cut valve
(FR - RL)
Ignition switch: ON (when initial check is
complete)
System voltage
79
Diagonal cut valve
(FL - RR)
Ignition switch: ON (when initial check is
complete)
System voltage
80
ABS solenoid valve OUT
(RL)
Ignition switch: ON (when initial check is
complete)
System voltage
81
ABS solenoid valve OUT
(FR)
Ignition switch: ON (when initial check is
complete)
System voltage
82
ECU earth
At all times
1 V or less
83
ASC-OFF switch
Ignition switch: ON
85
M/T identification input
At all times
86
ASC-ON switch
Ignition switch: ON
88
89
Brake warning lamp
Accumulator stroke
switch (FR - RL)
Ignition switch: ON
Ignition switch: ON
ASC switch: Pressed
to ON
1 V or less
ASC switch: Released
System voltage
1 V or less
ASC switch: Pressed
to ON
1 V or less
ASC switch: Released
System voltage
When lamp is off
System voltage
When lamp is on
1 V or less
Accumulator
sure*: Held
pres-
Accumulator
pressure*: Released
4.5 - 5.5 V
0V
35C-44
ASC - Troubleshooting
Terminal
No.
Check item
Check condition
90
Accumulator
stroke
switch (Fl - RR)
Ignition switch: ON
Normal condition
Accumulator
sure*: Held
pres-
Accumulator
pressure*: Released
4.5 - 5.5 V
0V
91
ABS solenoid valve IN
(RL)
Ignition switch: ON (when initial check is
complete)
System voltage
92
ABS solenoid valve IN
(FR)
Ignition switch: ON (when initial check is
complete)
System voltage
NOTE
*: The pressure inside the accumulators can be held and released by carrying out actuator tests. (Refer
to P.35C-39.)
35C-45
ASC - Troubleshooting
RESISTANCE AND CONTINUITY BETWEEN HARNESS-SIDE CONNECTOR TERMINALS CHART
(1) Resistance measurements and continuity checks should be carried out with the ignition switch at
OFF and the ASC-ECU connector disconnected.
(2) Resistance measurements and continuity checks should be made between the terminals indicated
below.
(3) The square terminal layout is shown in the diagram below.
Terminal No.
Signal name
Normal condition
1 - Body earth
ABS OUT solenoid valve (FL)
3.1 - 3.4 W
2 - Body earth
ABS OUT solenoid valve (RR)
3.1 - 3.4 W
3 - Body earth
Diagonal booster valve (FR - RL)
6.3 - 6.9 W
13 - Body earth
ECU earth
Continuity
14 - Body earth
ABS IN solenoid valve (FL)
6.3 - 6.9 W
15 - Body earth
ABS IN solenoid valve (RR)
6.3 - 6.9 W
16 - Body earth
Diagonal booster valve (FL - RR)
6.3 - 6.9 W
25 - Body earth
ECU earth
Continuity
32 - 40
Wheel speed sensor (RL)
1.0 - 1.5 kW
33 - 41
Wheel speed sensor (FR)
1.0 - 1.5 kW
34 - 42
Wheel speed sensor (RR)
1.0 - 1.5 kW
35 - 43
Wheel speed sensor (FL)
1.0 - 1.5 kW
53 - Body earth
Motor monitoring
Continuity
54 - Body earth
Valve relay monitoring
Continuity
78 - Body earth
Diagonal cut valve (FR - RL)
6.3 - 6.9 W
79 - Body earth
Diagonal cut valve (FL - RR)
6.3 - 6.9 W
80 - Body earth
ABS OUT solenoid valve (RL)
3.1 - 3.4 W
81 - Body earth
ABS OUT solenoid valve (FR)
3.1 - 3.4 W
85 - Body earth
M/T identification input
Continuity
82 - Body earth
ECU earth
Continuity
91 - Body earth
ABS IN solenoid valve (RL)
6.3 - 6.9 W
92 - Body earth
ABS IN solenoid valve (FR)
6.3 - 6.9 W
26 - Body earth
35C-46
ASC - On-vehicle Service
ON-VEHICLE SERVICE
Pressure gauge
Master cylinder
pressure sensor
MB991348
MASTER CYLINDER PRESSURE SENSOR
CHECK
1. Connect a pressure gauge to the output side of the
pressure sensor’s fluid line.
2. Bleed the air from the pressure sensor and the brake
line.
3. Disconnect the pressure sensor connector and connect
the special tool in between the connectors.
4. Start the engine and check that the output voltage between
terminal (2) and earth is within the standard value range
for the following hydraulic pressures when the brake pedal
is depressed.
Standard values:
Hydraulic pressure MPa
Output voltage
0
0.4 - 0.6
9.8
2.4 - 2.6
5. If the output voltages are outside the standard value
ranges, check that there are no problems in the power
supply line and earth, and then replace the sensor.
35C-47
ASC - On-vehicle Service
SOLENOID VALVE CHECKS
ABS SOLENOID VALVES
1. Measure the resistances between the terminals and check
that they are within the standard value ranges.
Standard values:
Item
Hydraulic unit
Check terminals
Resistance between terminals
Front-right
side
IN
11 - 22
6.3 - 6.9 W
OUT
5 - 22
3.1 - 3.4 W
Front-left
side
IN
12 - 21
6.3 - 6.9 W
OUT
6 - 21
3.1 - 3.4 W
Rear-right
side
IN
9 - 21
6.3 - 6.9 W
OUT
3 - 21
3.1 - 3.4 W
Rear-left
side
IN
10 - 22
6.3 - 6.9 W
OUT
4 - 22
3.1 - 3.4 W
2. If the resistances between the terminals are higher than
the standard values, replace the hydraulic unit.
ASC solenoid valves
1. Measure the resistance between the terminals and check
that they are within the standard value ranges.
Standard values:
Item
Check terminals
Resistance
between terminals
Diagonal accumulator
valve
FR - RL
2 - 21
3.1 - 3.4 W
FL - RR
8 - 22
3.1 - 3.4 W
Diagonal cut
valves
FR - RL
1 - 21
6.3 - 6.9 W
FL - RR
7 - 22
6.3 - 6.9 W
2. If the resistances between the terminals are higher than
the standard values, replace the hydraulic unit.
MOTOR OPERATION CHECK
Connect the battery (+) terminal to terminal (24) and the ( - )
terminal to terminal (23), and then check that the sound of
the hydraulic unit motor operating can be heard.
Caution
The battery power should not be applied for any more
than 1 second.
35C-48
<L.H. drive vehicles>
ASC - On-vehicle Service
VALVE RELAY CONTINUITY CHECK
Item
Terminal No.
1
When power is not
supplied
When power is supplied
<R.H. drive vehicles>
2
3
4
5
35C-49
ASC - Master Cylinder and Brake Booster
MASTER CYLINDER AND BRAKE BOOSTER
REMOVAL AND INSTALLATION
Pre-removal Operation
Brake Fluid Draining
Post-installation Operation
D Brake Fluid Supplying
D Brake Line Bleeding
D Brake Pedal Adjustment
5
4
2
11
1 23 Nm
23 Nm
8
1
1
22 Nm
10 Nm
9
1
23 Nm
14 Nm
7
10
3
<L.H. drive vehicles>
<R.H. drive vehicles>
5
6 15 Nm 5
7
6
15 Nm
Removal steps
1. Brake pipe connection
2. Brake fluid level sensor connector
3. Master cylinder pressure sensor
4. Master cylinder assembly
"BA D Push rod protruding length check and
adjustment
"AA 5. Vacuum hose
(with built-in check valve)
6. Fitting
Sealant: 3M ATD Part No.
8661 or equivalent
7.
8.
9.
10.
11.
Snap pin
Pin assembly
Clevis
Brake booster
Sealer
NOTE
Refer to GROUP 35A of the ’97 GALANT Workshop
Manual for installation service points.
35C-50
ASC - Master Cylinder and Brake Booster
MASTER CYLINDER
DISASSEMBLY AND REASSEMBLY
1
7
2
3
11
12
4
13
5
Master cylinder kit
8
9
14
11
12
7
13
10
13
14
12
Brake fluid: DOT3 or DOT4
Disassembly steps
1. Reservoir cap assembly
2. Reservoir cap
3. Diaphragm
4. Filter
5. Brake fluid level indicator assembly
6. Float
7. Spring pin
AA"
8.
9.
10.
11.
12.
13.
14.
Reservoir tank
Reservoir seal
Pin
Piston stopper ring
Primary piston assembly
Secondary piston assembly
Master cylinder body
DISASSEMBLY SERVICE POINT
AA" PISTON STOPPER RING REMOVAL
Remove the piston stopper ring while depressing the piston.
INSPECTION
D
D
D
Check the inner surface of master cylinder body for rust
or pitting.
Check the primary and secondary pistons for rust, scoring,
wear, damage or wear.
Check the diaphragm for cracks and wear.
ASC - Motor Relay/Hydraulic Unit
35C-51
MOTOR RELAY
<L.H. drive vehicles>
Motor relay
REMOVAL SERVICE POINT
Caution
The motor relay may become hot immediately after
driving, so take care when handling the motor relay.
<R.H. drive vehicles>
Motor relay
HYDRAULIC UNIT
REMOVAL AND INSTALLATION
Refer to GROUP 35B of ’97 GALANT Workshop Manual.
1
2 3 4
5
INSTALLATION SERVICE POINT
6
BRAKE PIPE INSTALLATION
Install the brake pipes to the hydraulic unit as shown in the
illustration.
1. From master cylinder (primary)
2. To front brake (L.H.)
3. To proportioning valve (rear R.H. brake)
4. To proportioning valve (rear L.H. brake)
5. To front brake (R.H.)
6. From master cylinder (secondary)
35C-52
ASC - Sensors
SENSORS
REMOVAL AND INSTALLATION
Caution
(1) SRS: Before removal of air bag module and clock spring, refer to ’97 GALANT Workshop Manual
GROUP 52B - Service Precautions and Air Bag Module and Clock Spring.
(2) Do not drop the sensors or subject them to shocks.
4
5 Nm
1
5
2
14 Nm
3
G sensor and yaw rate sensor
removal steps
D Floor console
1. Yaw rate sensor
2. Lateral G sensor
3. G sensor bracket
AA"
Steering wheel sensor removal steps
D Steering wheel and column cover
(Refer to ’97 GALANT Workshop
Manual - GROUP 37A - Steering
Wheel and Shaft.)
4. Steering wheel sensor
Pressure sensor removal steps
5. Master cylinder pressure sensor
(Refer to P. 35C-49.)
NOTE
Refer to GROUP 35B of the ’97 GALANT Workshop Manual for the wheel speed sensors.
ASC - Sensors
35C-53
REMOVAL SERVICE POINT
Slit plate
AA" STEERING WHEEL SENSOR REMOVAL
Steering
wheel sensor
Caution
1. Do not adhere any dust or grease, etc. to the steering
wheel sensor, which has a photo coupler in it.
2. Do not bend the slit plate of the column switch nor
adhere any grease etc. to it.
CHECKS
Label
LATERAL G SENSOR CHECK
1. Disconnect the G sensor connector and connect the
special tool in between the connectors.
2. Turn the ignition switch to ON and take a reading of
the output voltage between terminal No. 2 and body earth.
Standard value: 2.4 - 2.6 V
MB991348
Label
3. With the special tool connected, hold the sensor so that
the label is facing sideways as shown in the illustration,
and take a reading of the output voltage between terminal
No. 2 and body earth.
Standard value: 3.3 - 3.7 V
4. If the voltage is outside the standard value, check that
there are no problems in the power supply line and earth,
and then replace the sensor.
YAW RATE SENSOR CHECK
1. Disconnect the yaw rate sensor connector and connect
the special tool in between the connectors.
2. Turn the ignition switch to ON and take a reading of
the output voltage between terminal No. 3 and body earth.
Standard value: 2.4 - 2.6 V
MB991348
3. With the special tool connected, remove the yaw rate
sensor from the G sensor bracket and take a reading
of the output voltage between terminal No. 3 and body
earth while turning the sensor to the left and right.
<Turned to the left> Voltage drops
<Turned to the right> Voltage rises
4. If the voltage does not drop when the sensor is turned
to the left and rise when it is turned to the right, check
that there are no problems in the power supply line and
earth, and then replace the sensor.
35C-54
ASC - ASC Switch
ASC SWITCH
REMOVAL AND INSTALLATION
2
1
Removal steps
1. Switch bezel
2. ASC switch
INSPECTION
ASC SWITCH CONTINUITY CHECK
ON
Neutral
OFF
Switch position
Terminal No.
1
ON
Neutral
OFF
2
3
6
4
-
5
35C-55
ASC - ASC-ECU
ASC-ECU
REMOVAL AND INSTALLATION
Pre-removal and Post-installation Operations
Glove box, glove box frame, side cover and corner panel removal and installation
3
5 Nm
5 Nm
2
Grounding bolt
1
AA"
Removal steps
1. Instrument panel lower passengerside bracket
2. ASC-ECU
3. Lower bracket
REMOVAL SERVICE POINT
AA" ASC-ECU REMOVAL
Loosen the dash harness mounting nut, lower the dash
harness until the ASC-ECU can be removed, and then remove
the ASC-ECU.
Dash harness
CHECKS
Refer to P.35C-41.
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