Mitsubishi Colt Ralliart. Manual - part 636

TROUBLESHOOTING

ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-89

Inspection Procedure 3: The ABS warning lamp and the ASC indicator lamp don't illuminate when the 
ignition switch is turned ON.

COMMENTS ON TROUBLE SYMPTOM

• Drive signal of the ABS warning lamp and the 

ASC indicator lamp (including bulb check) is sent 
from the ASC-ECU to the combination meter 
through the CAN communication lines.

• If the combination meter detects a ASC time-out 

due to a failure in abnormal CAN communication, 
the combination meter illuminates the lamp.

• The ABS warning lamp and the ASC indicator 

lamp are non-replaceable LED. If the lamp is 
blown, replace the combination meter.

• Perform the actuator test to illuminate the lamps 

in the combination meter. If the lamp does not 
illuminate, replace the combination meter assem-
bly. If the lamp illuminates, replace the ASC-ECU.

PROBABLE CAUSES

• Damaged wiring harness and connectors

• Combination meter assembly malfunction

• ASC-ECU malfunction

DIAGNOSTIC PROCEDURE

STEP 1. M.U.T.-III actuator test for other systems
(1) Ignition switch: ON 
(2) Execute combination meter actuator test.

• Item A0: Indicator lamp and warning lamp

OK: Illuminates

Q: Is the check result normal?

YES : 

Go to Step 2.

NO : 

Replace the combination meter assembly.

STEP 2. M.U.T.-III diagnosis code for other 
systems
Check if the combination meter-related diagnosis 
code is set.

Q: Is the diagnosis code set?

YES : 

Troubleshoot the combination meter. (Refer 

to GROUP 54A 

− Troubleshooting 

P.54A-31

)

NO : 

Replace the ASC-ECU, and then go to Step 
3.

STEP 3. Retest the system.

Q: Do the ABS warning lamp and the ASC indicator 

lamp illuminate when the ignition switch is turned 
ON?
YES : 

This diagnosis is complete.

NO : 

Replace the combination meter assembly.

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TROUBLESHOOTING

ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-90

Inspection Procedure 4: ABS warning lamp and ASC indicator lamp do not extinguish after the engine 
is started.

COMMENTS ON TROUBLE SYMPTOM

• Drive signal of the ABS warning lamp and the 

ASC indicator lamp (including bulb check) is sent 
from the ASC-ECU to the combination meter 
through the CAN communication lines.

• If the combination meter detects a ASC time-out 

due to a failure in abnormal CAN communication, 
the combination meter illuminates the lamp.

• When malfunction occurs in the ASC-ECU power 

supply (i.e. excessively high resistance in the 
power supply or earth lines), this trouble symp-
tom will appear, but the diagnosis code will not be 
set. If the vehicle is run at 15 km/h or more after 
that, the ASC-ECU set the diagnosis code No. 
C1861.

• Perform the actuator test to extinguish the lamp 

in the combination meter. If the lamp does not 
extinguish, replace the combination meter ASSY. 
If the lamp extinguishes, replace the ASC-ECU.

• The ABS warning lamp and the ASC indicator 

lamp are non-replaceable LED. If the lamp is 
blown, replace the combination meter.

• When malfunction occurs in the steering wheel 

sensor or the ASC-ECU power supply system 
and earth system, the ABS warning lamp may 
illuminate when the ignition system is turned ON 
even after returning to the normal condition. In 
this case, the ABS warning lamp goes out when 
the ASC-ECU finishes self-check operation of the 
following items.

• Steering wheel sensor: Self-check operation 

is finished at approximately 10km/h.

• ASC-ECU: Self-check operation is finished at 

approximately 15 km/h.

PROBABLE CAUSES

• Damaged wiring harness and connectors

• Combination meter assembly malfunction

• ASC-ECU malfunction

DIAGNOSTIC PROCEDURE

STEP 1. M.U.T.-III CAN bus diagnostics
Use the M.U.T.-III to diagnose the CAN bus lines.

Q: Is the check result normal?

YES : 

Go to Step 3.

NO : 

Repair the CAN bus lines. (Refer to GROUP 
54D 

− Troubleshooting 

P.54D-13

.) On 

completion, go to Step 2.

STEP 2. M.U.T.-III diagnosis code

Q: Is the diagnosis code No. C1861 set?

YES : 

Carry out the diagnosis for the diagnosis 

code.(Refer to 

P.35C-72

.)

NO : 

Go to Step 3.

STEP 3. M.U.T.-III actuator test for other systems
(1) Ignition switch: ON 
(2) Execute combination meter actuator test.

• Item A1: Indicator lamp and warning lamp

OK: OFF

Q: Is the check result normal?

YES : 

Replace the ASC-ECU, and then go to Step 

4.

NO : 

Replace the combination meter assembly.

STEP 4. Retest the system.

Q: Do the ABS warning lamp and the ASC indicator 

lamp illuminate when the ignition switch is turned 
ON?
YES : 

This diagnosis is complete.

NO : 

Replace the combination meter assembly.

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TROUBLESHOOTING

ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-91

Inspection Procedure 5: Brake warning lamp does not illuminate at all.

COMMENTS ON TROUBLE SYMPTOM

• When EBD is abnormal and the brake fluid level 

is low, the ASC-ECU sends the brake warning 
lamp drive signal to the combination meter 
through the CAN communication lines.

• The ASC-ECU sends the lamp drive signal to the 

combination meter during a bulb check (for three 
seconds after the ignition switch is turned on) 
through the CAN communication lines, and then 
the combination meter activates the lamp.

• If the combination meter detects a ASC time-out 

due to a failure in abnormal CAN communication, 
the combination meter illuminates the lamp.

PROBABLE CAUSES

• Damaged wiring harness and connectors

• Combination meter assembly malfunction

DIAGNOSTIC PROCEDURE

STEP 1. M.U.T.-III actuator test for other systems
(1) Ignition switch: ON 
(2) Execute combination meter actuator test.

• Item A0: Indicator lamp and warning lamp

OK: Illuminates

Q: Is the check result normal?

YES : . 

Go to Step 2.

NO : . 

Replace the combination meter assembly.

STEP 2. M.U.T.-III diagnosis code for other 
systems
Check if the combination meter-related diagnosis 
code is set.

Q: Is the diagnosis code set?

YES : 

Troubleshoot the combination meter. (Refer 

to GROUP 54A 

− Troubleshooting 

P.54A-31

)

NO : 

Replace the ASC-ECU, and then go to Step 
3.

STEP 3. Retest the system.

Q: Do the ABS warning lamp and the ASC indicator 

lamp illuminate when the ignition switch is turned 
ON?
YES : 

This diagnosis is complete.

NO : 

Replace the combination meter assembly.

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TROUBLESHOOTING

ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-92

Inspection Procedure 6: Brake warning lamp does not illuminate when the parking brake is operated. 
(Illuminates when the bulb check is operated.)

COMMENTS ON TROUBLE SYMPTOM

• When the parking brake is operated, the 

ASC-ECU sends the brake warning lamp drive 
signal to the combination meter through the CAN 
communication lines.

• The ASC-ECU sends the lamp drive signal to the 

combination meter during a bulb check (for three 
seconds after the ignition switch is turned on) 
through the CAN communication lines, and then 
the combination meter activates the lamp.

• If the combination meter detects a ASC time-out 

due to a failure in abnormal CAN communication, 
the combination meter illuminates the lamp.

PROBABLE CAUSES

• Damaged wiring harness and connectors

• Parking brake switch malfunction

• Combination meter assembly malfunction

• ASC-ECU malfunction

DIAGNOSTIC PROCEDURE

STEP 1. M.U.T.-III data list
Using the data list, check that the parking brake input 
signal is normal. (Refer to 

P.35C-109

.)

• Item No.28: side brake switch

Q: Is the check result normal?

YES : 

Go to Step 6.

NO : 

Go to Step 2.

STEP 2. Check A-05 ASC-ECU connector and 
C-44 parking brake switch connector.

Q: Is the check result normal?

YES : 

Go to Step 3.

NO : 

Repair.

Parking Brake Switch Circuit

Wire colour code
B : Black     LG : Light green
G : Green     L : Blue      
W : White     Y : Yellow
SB : Sky blue     BR : Brown 
O : Orange     GR : Grey  
R : Red     P : Pink     
V : Violet     PU : Purple

ASC-ECU

PARKING 
BRAKE 
SWITCH

AC601083

Connector: A-05

AB

A-05(Black)

Harness side

AC601093

Connector: C-44

AD

C-44(Black)

Harness side

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