Mitsubishi Colt Ralliart. Manual - part 625

TROUBLESHOOTING

ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-45

STEP 24. Diagnosis code recheck
Recheck if the diagnosis code is set.
(1) Erase the diagnosis code.
(2) Ignition switch: LOCK (OFF) position
(3) Ignition switch: ON

Q: Is the diagnosis code No. C1225 set?

YES : . 

Intermittent malfunction (Refer to GROUP 

00 

− How to Cope with Intermittent 

Malfunction 

P.00-13

.)

NO : . 

This diagnosis is complete.

Code No. C1226: Control solenoid valve (FR) pressure holding system

 

Code No. C1231: Control solenoid valve (FR) decompressing system

 

Code No. C1236: Control solenoid valve (FL) pressure holding system

 

Code No. C1241: Control solenoid valve (FL) pressure reducing system

 

Code No. C1246: Control solenoid valve (RR) pressure holding system

 

Code No. C1251: Control solenoid valve (RR) pressure reducing system

 

Code No. C1256: Control solenoid valve (RL) pressure holding system

 

Code No. C1261: Control solenoid valve (RL) decompressing system

 

Code No. C1300: Cut valve (FR/RL) <primary> system

 

Code No. C1305: Suction valve (FR/RL) <primary> system

 

Code No. C1310: Cut valve (FL/RR) <secondary> system

 

Code No. C1315: Suction valve (FL/RR) <secondary> system

CAUTION

If there is any problem in the CAN bus lines, an 
incorrect diagnosis code may be set. Prior to this 
diagnosis, always diagnose the CAN bus lines.

OPERATION

• ASC-ECU contains the power supply circuit (ter-

minal No. 44) for the solenoid valve, cut valve, 
and suction valve. The solenoid valve, cut valve, 
and suction valve are energised by the valve 
relay, which is incorporated in ASC-ECU.

• The valve relay, which is incorporated in 

ASC-ECU, is energising the solenoid valve, cut 
valve, ad suction valve unless the initial check is 
in progress when the ignition switch is turned on, 
or the recurrent system check is in progress.

• ASC-ECU activates the solenoid valve by turning 

on its driving transistor.

DIAGNOSIS CODE SET CONDITIONS

Code No. C1226, C1231, C1236, C1241, C1246, 

C1251, C1256 and C1261.

• These codes are set when the ASC-ECU drive 

signal does not match the feed back signal from 
the solenoid valve.

Code No. C1300, C1305, C1310, and C1315

• These codes are set when an abnormality is 

detected in ASC-ECU.

PROBABLE CAUSES

• Damaged wiring harness and connectors

• 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 : 

Replace the ASC-ECU.

NO : 

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

P.54D-13

.) On 

completion, go to Step 2.

STEP 2. Diagnosis code recheck after resetting 
CAN bus lines

Q: Are the diagnosis code C1226, C1231, C1236, 

C1241, C1246, C1251, C1256, C1261, C1300, C1305, 
C1310, and C1315 set?
YES : 

Replace the ASC-ECU.

NO : 

This diagnosis is complete.

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Index

Group

TOC

TROUBLESHOOTING

ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-46

Code No. C1266: Motor relay seizure

 

Code No. C1273: Motor relay stuck OFF

 

Code No. C1274: Motor relay stuck ON

CAUTION

If there is any problem in the CAN bus lines, an 
incorrect diagnosis code may be set. Prior to this 
diagnosis, always diagnose the CAN bus lines.

OPERATION

• ASC-ECU contains the power supply circuit (ter-

minal 45) for the pump motor. The pump motor is 
energised by the motor relay, which is incorpo-
rated in ASC-ECU.

• The motor relay, which is incorporated in 

ASC-ECU, is always off unless the motor sole-
noid valve check is activated when the vehicle is 
started.

• ASC-ECU activates the pump motor by turning 

on the ECU built-in motor relay when ABS or 
ASC is working.

Hydraulic unit (Motor and Solenoid Valve) 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

FUSIBLE 
LINK

FUSIBLE 
LINK

3

5

ASC-ECU

HYDRAULIC UNIT

SOLENOID
VALVE 
POWER 
SOURCE

ABS SOLENOID VALVE 

MOTOR

MOTOR 
POWER 
SOURCE

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TROUBLESHOOTING

ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-47

DIAGNOSIS CODE SET CONDITIONS

These diagnostic trouble codes will be set under the 
cases below.

Code No. C1266: Motor relay seizure

• The ABS-ECU monitors the voltage, which is cre-

ated by the pump motor coasting, after the motor 
relay is turned off. If the voltage continues only for 
too short period, the ECU determines that the 
pump motor is not running smoothly (i.e. motor 
seizure), and sets this diagnosis code.

Code No. C1273: Motor relay stuck OFF

• If the voltage, which is created by the pump 

motor, is abnormal after the motor relay is turned 
on, the ECU determines that the motor relay is 
stuck off, and sets this diagnosis code.

Code No. C1274: Motor relay stuck ON

• If the voltage, which is created by the pump 

motor, is abnormal after the motor relay is turned 
off, the ECU determines that the motor relay is 
stuck on, and sets this diagnosis code.

PROBABLE CAUSES

Current trouble

• Damaged wiring harness and connectors

• ASC-ECU malfunction

Past trouble

• Carry out diagnosis with particular emphasis on 

connector(s) or wiring harness between the 
power supply circuit (terminal 45) to the 
ASC-ECU motor or earth circuit (terminal 46). For 
diagnosis procedures, refer to How to treat past 
trouble (GROUP 00 

− How to Use Troubleshoot-

ing/Inspection Service Points 

P.00-13

).

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. Diagnosis code recheck after resetting 
CAN bus lines

Q: Has diagnosis code C1266, C1273 or C1274 been 

set?
YES : 

Go to Step 3.

NO : 

This diagnosis is complete.

STEP 3. Voltage measurement: A-05 ASC-ECU 
connector

(1) Disconnect the connector, connect the ABS 

check harness (Special tool: MB991984) to the 
harness-side connector, and measure the voltage 
at the special tool connector side.
NOTE: Do not connect the special tool to 
ASC-ECU.

(2) Ignition switch: ON
(3) Measure the voltage between the terminal No. 45 

and the body earth.

OK: Battery voltage

Q: Is the check result normal?

YES : 

Go to Step 5.

NO : 

Go to Step 4.

AC601083

Connector: A-05

AB

A-05(Black)

Harness side

AC601085AD

MB991984

ASC-ECU

Check connector

ASC-ECU harness connector

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TROUBLESHOOTING

ACTIVE STABILITY CONTROL SYSTEM (ASC)

35C-48

STEP 4. Connector check: A-05 ASC-ECU 
connector

Q: Is the check result normal?

YES : 

The open or short circuit may be present in 

the power supply circuit to the motor. Repair 
the harness wire between the ASC-ECU 
connector terminal No. 45 and the fusible 
link No. 3. Then go to Step 8.

NO : 

Repair the connector, and then go to Step 8.

STEP 5. Measure the resistance at A-05 ASC-ECU 
connector.

(1) Disconnect the connector, connect the ABS 

check harness (Special tool: MB991984) to the 
harness-side connector, and measure the voltage 
at the special tool connector side.
NOTE: Do not connect the special tool to 
ASC-ECU.

(2) Measure the resistance between terminal No. 46 

and the body earth.

OK: Continuity exists (2 

Ω or less)

Q: Is the check result normal?

YES : 

Go to Step 7.

NO : 

Go to Step 6.

AC601083

Connector: A-05

AB

A-05(Black)

Harness side

AC601083

Connector: A-05

AB

A-05(Black)

Harness side

AC601085AE

MB991984

ASC-ECU

Check connector

ASC-ECU harness connector

Main

Index

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TOC