Mitsubishi Colt Ralliart. Manual — part 453

Power Supply and Earth Circuit

FUSIBLE
LINK

IGNITION
SWITCH (IG1)

4

ABS

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 : Grey R : Red P : Pink V : Violet PU : Purple

TROUBLESHOOTING

POWER STEERING

37-79

COMMENTS ON TROUBLE SYMPTOM

Intermittent failure may be present in the power sup-
ply system. Check the power supply and earth to the
ECU, ignition signal, the battery and the alternator to
confirm that normal direct current flows.

PROBABLE CAUSES

• Defective harness wire(s) or connector(s)

• Malfunction of the charging system

• Malfunction of the electric power steering-ECU

Main

Index

Group

TOC

TROUBLESHOOTING

POWER STEERING

37-80

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III CAN bus diagnostics

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.
(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.

Q: Is the check result normal?

YES : .

Go to Step 2.

NO : .

Repair the CAN bus line (Refer to GROUP

54D, Diagnosis

P.54D-13

).

STEP 2. Check the connectors and terminals.

•

AC314189AE

Connector: B-37, B-38

B-37

B-38

Harness side

B-37

21
22

B-38

Electric power steering-ECU connectors B-37 and

B-38

Check the connectors above for improper engage-
ment, terminal damage or terminal drawn in the con-
nector case.

Q: Are the connectors and terminals in good

condition?
YES :

Go to Step 3.

NO :

Repair the harness connector.

Main

Index

Group

TOC

TROUBLESHOOTING

POWER STEERING

37-81

STEP 3. Voltage measurement at electric power
steering-ECU connector B-37.

•

AC314189AF

Connector: B-37

Harness side

Disconnect the connector, and measure at the wiring

harness side.

• Ignition switch: ON

•

AC313972 BW

Harness side

B-37

Measure the voltage between electric power steer-

ing-ECU connector B-37 terminal No.5 and body
earth

OK: system voltage

Q: Is the check result normal?

YES :

Go to Step 4.

NO :

Go to Step 6.

STEP 4. Voltage measurement at electric power
steering-ECU connector B-38.

•

AC314189

AC314189

AC314189AG

Connector: B-38

Harness side

Disconnect the connector, and measure at the wiring

harness side.

•

AC313972 BX

Harness side
connector B-38
(Rear view)

Measure the voltage between electric power steer-

ing-ECU connector B-38 terminal No.22 and
body earth

OK: system voltage

Q: Is the check result normal?

YES :

Go to Step 5.

NO :

Go to Step 7.

Main

Index

Group

TOC

TROUBLESHOOTING

POWER STEERING

37-82

STEP 5. Resistance measurement at electric
power steering-ECU connector B-38.

•

AC314189

AC314189

AC314189AG

Connector: B-38

Harness side

Disconnect the connector, and measure at the wiring

harness side.

•

AC313972 BY

Harness side
connector B-38
(Rear view)

Measure the resistance between electric power

steering-ECU connector B-38 terminal No.21 and
body earth

OK: Continuity exists (2

Ω or less)

Q: Is the check result normal?

YES :

Go to Step 9.

NO :

Go to Step 8.

STEP 6. Check the harness wires.
NOTE:

AC313870AI

Connector: B-110

Junction Block (Front view)

Junction block side

12

5

9

8

1 2

1011

3 4

14

13

6 7

AC313872AJ

Connector: B-129

Junction Block (Rear view)

Junction block side

Prior to this harness wire check, check junction block
connectors B-110 and B-129, and repair if necessary.

•

AC314189AF

Connector: B-37

Harness side

AC313874AC

Connector: B-141

Harness side

The harness wire between electric power steer-

ing-ECU connector B-37 and ignition switch (IG1)
B-141

Check the harness wire above for damage or other
problem.

Q: Is the harness wire in good condition?

YES :

Go to Step 11.

NO :

Repair the harness wire.

Main

Index

Group

TOC