Mitsubishi Colt Ralliart. Manual - part 444

TROUBLESHOOTING

POWER STEERING

37-43

STEP 3. Check whether the diagnosis code is 
reset.

AC206895

AC

Diagnosis

connector

MB991827

MB991824 

MB991910

CAUTION

Before connecting or disconnecting the 
M.U.T.-III, turn the ignition switch to the "LOCK" 
(OFF) position.
Check again if the diagnosis code is set.
(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) Start the engine and move the steering wheel to 

the right and left.

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

position.

(8) Disconnect M.U.T.-III.

Q: Is diagnosis code C1534 set?

YES : 

Replace the electric power steering-ECU 

(Refer to 

P.37-102

).

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

.

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Index

Group

TOC

TROUBLESHOOTING

POWER STEERING

37-44

Code No.C1542 Fail-safe relay stuck off

CAUTION

• If the electric power steering-ECU sets diagnosis code No.C1542, diagnose the CAN bus lines. If 

there is any fault in the CAN bus lines, an incorrect diagnosis code may be set.

•

ELECTRIC POWER STEERING-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

Motor Circuit

Whenever the ECU is replaced, ensure that the communication circuit is normal.

DIAGNOSIS CODE SET CONDITIONS

• Although the fail-safe relay (power relay) is 

turned on, the system is not energised and the 
microcomputer determines that the relay contact 
is open.

• The fail-safe relay (power relay) is not turned on 

and the microcomputer determines that the relay 
contact is open.

Criteria for judging malfunction

• Power supply voltage is less than 8 V and the 

difference between the ignition voltage and 
the power supply voltage is more than 2.5 V 
when the fail-safe relay is off.

PROBABLE CAUSES

• Defective wire(s) or connector(s) in the power 

supply circuit to the electric power steering-ECU

• Malfunction of the electric power steering-ECU

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Index

Group

TOC

TROUBLESHOOTING

POWER STEERING

37-45

DIAGNOSTIC PROCEDURE

STEP 1. M.U.T.-III diagnosis code

AC206895

AC

Diagnosis

connector

MB991827

MB991824 

MB991910

CAUTION

Before connecting or disconnecting the 
M.U.T.-III, turn the ignition switch to the "LOCK" 
(OFF) position.
Check again if the diagnosis code is set.
(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) Start the engine, and check the diagnosis code.
(6) Turn the ignition switch to the "LOCK" (OFF) 

position.

Q: Are diagnosis codes C1542 and C1531 set 

simultaneously?
YES : 

Go to Step 2.

NO : 

Go to Step 4.

STEP 2. Check the motor wires of the steering 
gear and linkage assembly wiring harness for 
short to earth.

AC314189AC

Connector: B-38-1

Harness side

Disconnect electric power steering-ECU connector 
B-38-1 and measure the resistance.

•

AC313972BV

Harness side
connector B-38-1
(Rear view)

Measure the resistance between electric power 

steering-ECU connector B-38-1 terminal 31 and 
body earth.

• Measure the resistance between electric power 

steering-ECU connector B-38-1 terminal 32 and 
body earth.

OK: Open circuit or more than 300 

Ω

Q: Is the check result normal?

YES : 

Go to Step 3.

NO : 

Replace the steering gear and linkage 
assembly (Refer to 

P.37-96

).

Main

Index

Group

TOC

TROUBLESHOOTING

POWER STEERING

37-46

STEP 3. Check whether the diagnosis code is 
reset.

AC206895

AC

Diagnosis

connector

MB991827

MB991824 

MB991910

CAUTION

Before connecting or disconnecting the 
M.U.T.-III, turn the ignition switch to the "LOCK" 
(OFF) position.
Check again if the diagnosis code is set.
(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) Start the engine, and check the diagnosis code.
(6) Turn the ignition switch to the "LOCK" (OFF) 

position.

Q: Are diagnosis codes C1542 and C1531 set?

YES : . 

Replace the electric power steering-ECU 

(Refer to 

P.37-102

). 

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

.

STEP 4. Check the motor wires of the steering 
gear and linkage assembly wiring harness for 
open circuit.

AC314189AC

Connector: B-38-1

Harness side

Disconnect electric power steering-ECU connector 
B-38-1 and measure the resistance.

•

AC400133AB

Harness side
connector B-38-1
 (Rear view)

Measure the resistance between electric power 

steering-ECU connector B-38-1 terminals 31 and 
32

OK: Continuity exists (2 

Ω or less)

Q: Is the check result normal?

YES : 

Go to Step 5.

NO : 

Repair the harness wire and connector, or 
replace the steering gear box and linkage 
assembly (Refer to 

P.37-96

).

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