Mitsubishi Colt Ralliart. Manual - part 237

TROUBLESHOOTING

ANTI-SKID BRAKING SYSTEM (ABS)

35B-40

Q: Is the result normal?

YES : 

Go to Step 3.

NO : 

Repair the wiring harness between the 
ABS-ECU and fusible link No.3.

STEP 3. Check whether the diagnosis code is 
reset.

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) Erase the diagnosis code.
(3) Turn the ignition switch to the "LOCK" (OFF) 

position.

(4) Turn the ignition switch to the "ON" position.
(5) Check if the diagnosis code is set.
(6) Turn the ignition switch to the "LOCK" (OFF) 

position.

(7) Disconnect M.U.T.-III.

Q: Is code No.C1273 set?

YES : 

Replace the hydraulic unit(integrated with 

ABS-ECU) (Refer to 

P.35B-78

).

NO : 

The malfunction is intermittent. Refer to 
GROUP 00, How to Use 
Troubleshooting/Inspection Service Points 

− 

How to Cope with Intermittent Malfunction 

P.00-13

.

AC206895

AC

Diagnosis

connector

MB991827

MB991824 

MB991910

Main

Index

Group

TOC

TROUBLESHOOTING

ANTI-SKID BRAKING SYSTEM (ABS)

35B-41

Code No.C1274: Motor relay stuck on

OPERATION

• The ABS-ECU contains the power supply circuit 

(terminal No.25) for the motor pump. The motor 
pump is energised by the pump relay, which is 
incorporated in the ABS-ECU.

• The pump relay, which is incorporated in the 

ABS-ECU, is always energising the motor pump 
unless the initial check is in progress when the 
ignition switch is turned on, or the recurrent sys-
tem check is in progress.

DIAGNOSIS CODE SET CONDITIONS

These diagnosis codes will be set under the cases 
below.

• 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

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)

IGNITION
SWITCH (IG1)

ELECTRIC
POWER
STEERING
SYSTEM

ABS-ECU

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

Power Supply Circuit

Main

Index

Group

TOC

TROUBLESHOOTING

ANTI-SKID BRAKING SYSTEM (ABS)

35B-42

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 26 and 

earth.

OK: 5 

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

AC313972BB

1

2

3

4

5

7

8

9

10

11

18

19

20

21

22

13

14

15

16

17

6

12

23

24

25

26

Check connector
 (Harness side)

Main

Index

Group

TOC

TROUBLESHOOTING

ANTI-SKID BRAKING SYSTEM (ABS)

35B-43

Q: Is the result normal?

YES : 

Go to Step 3.

NO : 

Repair the wiring harness between the 
ABS-ECU and the battery.

STEP 3. Check whether the diagnosis code is 
reset.

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) Erase the diagnosis code.
(3) Turn the ignition switch to the "LOCK" (OFF) 

position.

(4) Turn the ignition switch to the "ON" position.
(5) Check if the diagnosis code is set.
(6) Turn the ignition switch to the "LOCK" (OFF) 

position.

(7) Disconnect M.U.T.-III.

Q: Is code No.C1274 set?

YES : 

Replace the hydraulic unit (integrated with 

ABS-ECU) (Refer to 

P.35B-78

).

NO : 

The malfunction is intermittent. Refer to 
GROUP 00, How to Use 
Troubleshooting/Inspection Service Points 

− 

How to Cope with Intermittent Malfunction 

P.00-13

.

AC206895

AC

Diagnosis

connector

MB991827

MB991824 

MB991910

Main

Index

Group

TOC