Mitsubishi Colt Ralliart. Manual - part 241

TROUBLESHOOTING

ANTI-SKID BRAKING SYSTEM (ABS)

35B-56

CAUTION

• If diagnosis code U1073 is set in the 

ABS-ECU, always diagnose the CAN main bus 
line. If there is any fault in the CAN bus lines, 
an incorrect diagnosis code may be set.

• Whenever the ECU is replaced, ensure that 

the communication circuit is normal.

TROUBLE JUDGMENT

This code is stored when the ABS-ECU has ceased 
the CAN communication (bus off). Then, if a penalty 
mode is entered after approximately five minutes, 
regular data transmission will be cancelled.

PROBABLE CAUSES

• Damaged wiring harness or connector

• Malfunction of the hydraulic unit (integrated with 

ABS-ECU)

DIAGNOSIS PROCEDURE

M.U.T.-III CAN bus diagnostics

CAUTION

Before connecting or disconnecting the 
M.U.T.-III, turn the ignition switch to the "LOCK" 
(OFF) position.
(1) Connect M.U.T.-III to the 16-pin diagnosis 

connector.

(2) Turn the ignition switch to the "ON" position.
(3) Diagnose the CAN bus line.
(4) Turn the ignition switch to the "LOCK" (OFF) 

position.

(5) Disconnect M.U.T.-III.

Q: Is the check result normal?

YES : 

The malfunction is intermittent. Refer to 

GROUP 00, How to Use 
Troubleshooting/Inspection Service Points 

− 

How to Cope with Intermittent Malfunction 

P.00-13

.

NO : 

Repair the CAN bus line (Refer to GROUP 
54D 

− Diagnosis 

P.54D-13

).

AC206895

AC

Diagnosis

connector

MB991827

MB991824 

MB991910

Main

Index

Group

TOC

TROUBLESHOOTING

ANTI-SKID BRAKING SYSTEM (ABS)

35B-57

INSPECTION CHART FOR TROUBLE 
SYMPTOMS

M1352011400813

NOTE: If steering movements are made when driv-
ing at high speed, or when driving on road surfaces 
with low frictional resistance, or when passing over 
bumps, the ABS may operate although sudden brak-
ing is not being applied. Because of this, when get-
ting information from the customer, check if the 
problem occurred while driving under such condi-
tions as these.

NOTE: During ABS operation, the brake pedal may 
vibrate a little or may not be able to be pressed. Such 
conditions are due to intermittent changes in hydrau-
lic pressure inside the brake line to prevent the 
wheels from locking. This is normal.

Trouble symptoms

Inspection procedure No. Reference page

Communication between M.U.T.-III and the 
ABS-ECU is not possible.

1

P.35B-58

ABS-ECU power supply system

2

P.35B-60

The ABS warning lamp does not illuminate with the 
ignition switch on.

3

P.35B-65

The ABS warning lamp does not extinguish after the 
engine is started.

4

P.35B-67

The ABS operates too frequently (no diagnosis code 
is set)

5

P.35B-71

Main

Index

Group

TOC

TROUBLESHOOTING

ANTI-SKID BRAKING SYSTEM (ABS)

35B-58

INSPECTION PROCEDURE FOR 
TROUBLE SYMPTOMS

Inspection Procedure 1: Communication between M.U.T.-III and the ABS-ECU is not possible.

FUSIBLE
LINK

ENGINE-CVT-ECU

DIAGNOSIS
CONNECTOR

FRONT SIDE

COMBINATION METER

ABS-ECU

6

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

CAN Communication Circuit

Main

Index

Group

TOC

TROUBLESHOOTING

ANTI-SKID BRAKING SYSTEM (ABS)

35B-59

COMMENTS ON TROUBLE SYMPTOM

If the M.U.T.-III cannot communicate with the ABS 
system, the CAN bus lines may be defective. If the 
ABS system does not work, the ABS-ECU or its 
power supply circuit may be defective. This symptom 
also appears when an incorrect vehicle model is 
selected on the M.U.T.-III.

POSSIBLE CAUSES

• Damaged harness wires and connectors

• The ABS-ECU is defective.

DIAGNOSIS PROCEDURE

M.U.T.-III CAN bus diagnostics

CAUTION

Before connecting or disconnecting the 
M.U.T.-III, turn the ignition switch to the "LOCK" 
(OFF) position.
(1) Connect M.U.T.-III to the 16-pin diagnosis 

connector.

(2) Turn the ignition switch to the "ON" position.
(3) Diagnose the CAN bus line.
(4) Turn the ignition switch to the "LOCK" (OFF) 

position.

(5) Disconnect M.U.T.-III.

Q: Is the check result normal?

YES : 

Replace the hydraulic unit (integrated with 

ABS-ECU) (Refer to 

P.35B-78

).

NO : 

Repair the CAN bus line (Refer to GROUP 
54D, Diagnosis 

P.54D-13

).

AC206895

AC

Diagnosis

connector

MB991827

MB991824 

MB991910

Main

Index

Group

TOC