Mitsubishi Colt Ralliart. Manual - part 238

TROUBLESHOOTING

ANTI-SKID BRAKING SYSTEM (ABS)

35B-44

Code No.C1276: Valve relay system

OPERATION

• The ABS-ECU contains the power supply circuit 

(terminal No.24) for the solenoid valve. The sole-
noid valve is energised by the valve relay, which 
is incorporated in the ABS-ECU.

• The valve relay, which is incorporated in the 

ABS-ECU, is always energising the solenoid 
valve unless the initial check is in progress when 
the ignition switch is turned on, or the recurrent 
system check is in progress.

DIAGNOSIS CODE SET CONDITIONS

These diagnosis codes will be set under the cases 
below.

• The ABS-ECU monitors the power supply voltage 

to the solenoid valve. If the voltage is lower than 
the predetermined value, the ECU sets this diag-
nosis code as a failure in the valve relay circuit.

PROBABLE CAUSES

The most likely causes for these diagnosis codes to 
set are:

• Damaged wiring harness or connector

• Malfunction of the hydraulic unit (integrated with 

ABS-ECU)

ABS-ECU

SOLENOID
VALVE POWER
SOURCE

MOTOR POWER SOURCE

MOTOR

SOLENOID VALVE

HYDRAULIC UNIT

FUSIBLE
LINK

FUSIBLE
LINK

CHARGING
SYSTEM

3

5

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

Hydraulic Unit (Motor and Solenoid Valve) Circuit

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TROUBLESHOOTING

ANTI-SKID BRAKING SYSTEM (ABS)

35B-45

DIAGNOSIS PROCEDURE

M.U.T.-III diagnosis code

CAUTION

Before connecting or disconnecting the 
M.U.T.-III, turn the ignition switch to the "LOCK" 
(OFF) position.
(1) Turn the ignition switch to the "ON" position.

(2) Check if the diagnosis code is set.
(3) Turn the ignition switch to the "LOCK" (OFF) 

position.

(4) Disconnect M.U.T.-III.

Q: Is code No.C1278 also set?

YES : 

Carry out the troubleshooting for diagnosis 

code No.C1278 (Refer to 

P.35B-46

).

NO : 

Replace the hydraulic unit (integrated with 
ABS-ECU) (Refer to 

P.35B-78

).

AC206895

AC

Diagnosis

connector

MB991827

MB991824 

MB991910

Main

Index

Group

TOC

TROUBLESHOOTING

ANTI-SKID BRAKING SYSTEM (ABS)

35B-46

Code No.C1278: Valve relay system stuck off

OPERATION

• The ABS-ECU contains the power supply circuit 

(terminal No.24) for the solenoid valve. The sole-
noid valve is energised by the valve relay, which 
is incorporated in the ABS-ECU.

• The valve relay, which is incorporated in the 

ABS-ECU, is always energising the solenoid 
valve unless the initial check is in progress when 
the ignition switch is turned on, or the recurrent 
system check is in progress.

DIAGNOSIS CODE SET CONDITIONS

• The ABS-ECU monitors the power supply voltage 

to the solenoid valve. If the voltage is lower than 
the predetermined value, the ECU sets this diag-
nosis code as a failure in the valve relay circuit.

PROBABLE CAUSES

The most likely causes for these diagnosis codes to 
set are:

• Damaged wiring harness or connector

• Malfunction of the hydraulic unit (integrated with 

ABS-ECU)

ABS-ECU

SOLENOID
VALVE POWER
SOURCE

MOTOR POWER SOURCE

MOTOR

SOLENOID VALVE

HYDRAULIC UNIT

FUSIBLE
LINK

FUSIBLE
LINK

CHARGING
SYSTEM

3

5

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

Hydraulic Unit (Motor and Solenoid Valve) Circuit

Main

Index

Group

TOC

TROUBLESHOOTING

ANTI-SKID BRAKING SYSTEM (ABS)

35B-47

DIAGNOSIS PROCEDURE

STEP 1. Check ABS-ECU connector A-05 for 
loose, corroded or damaged terminals, or 
terminals pushed back in the connector.

Q: Is the check result normal?

YES : 

Go to Step 2.

NO : 

Repair or replace the damaged 
component(s). Refer to GROUP 00, How to 
Use Troubleshooting/Inspection Service 
Points 

− Connector Inspection Service 

Points 

P.00-11

. 

STEP 2. Resistance measurement at ABS-ECU 
connector A-05.

(1) Disconnect the connector A-05, and connect 

special tool ABS Check Harness (MB991951) to 
the wiring harness-side connector.
NOTE: Do not connect special tool ABS Check 
Harness (MB991951) to the ABS-ECU.

(2) Measure the resistance between terminal 24 and 

battery terminal.

OK: 10 

Ω or less

AC313863AB

Connector: A-05

Harness side

A-05(B)

AC313863AB

Connector: A-05

Harness side

A-05(B)

AC314249AB

ABS-ECU

MB991951

Check connector

A-05 Harness connector

AC313972 BG

Check connector 
 (Harness side)

Main

Index

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