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.

Main

Index

Group

TOC

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.

Main

Index

Group

TOC

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.

Main

Index

Group

TOC

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

Main

Index

Group

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