Mitsubishi Lancer (4A9 engine). Manual - part 258

TROUBLESHOOTING

CONTROLLER AREA NETWORK (CAN)

54C-56

STEP 17. M.U.T.-III CAN bus diagnostics 
(checking the AS&G-ECU for internal short to 
earth)

CAUTION

Strictly observe the specified wiring harness 
repair procedure. For details refer to .
Disconnect C-64 AS&G-ECU connector, and diag-
nose the CAN bus line.

ACB01921AB

M.U.T.

JC

JC

SAS

KOS/
WCM

SRS

A/C

AUDIO

METER

AT/

CVT

EPS

ENGINE

ETACS

ABS/

ASC

MMCS

: Red section on screen

AS&G

Levelling

Cor ner

JC

OK: The display of the M.U.T.-III is as shown 
in the figure.

Q: Does M.U.T.-III screen correspond to the 

illustration?
YES : 

Repair the wiring harness between C-64 

AS&G-ECU connector and C-124 joint 
connector (CAN3).

NO : 

Check the transmission assembly 
connector, and repair if necessary. If the 
AS&G-ECU connector is in good condition, 
replace the AS&G-ECU.

STEP 18. M.U.T.-III CAN bus diagnostics 
(checking the engine-ECU for internal short to 
earth)

CAUTION

Strictly observe the specified wiring harness 
repair procedure. For details refer to .
Disconnect B-09 <Petrol> or B-40 <Diesel> engine-
ECU connector, and diagnose the CAN bus line.

ACB01921AB

M.U.T.

JC

JC

SAS

KOS/
WCM

SRS

A/C

AUDIO

METER

AT/

CVT

EPS

ENGINE

ETACS

ABS/

ASC

MMCS

: Red section on screen

AS&G

Levelling

Cor ner

JC

OK: The display of the M.U.T.-III is as shown 
in the figure.

Q: Does M.U.T.-III screen correspond to the 

illustration?
YES : 

Repair the wiring harness between B-09 

<Petrol> or B-40 <Diesel> engine-ECU 
connector and C-124 joint connector 
(CAN3).

NO  : 

Check the engine-ECU connector, and 
repair if necessary. If the engine-ECU 
connector is in good condition, replace the 
engine-ECU.

TROUBLESHOOTING

CONTROLLER AREA NETWORK (CAN)

54C-57

Diagnosis Item 6: Diagnose when the M.U.T.-III cannot receive the data sent by steering wheel sensor 
<vehicles with ASC or AFS>

CAUTION

When servicing a CAN bus line, earth yourself by touching a metal object such as an unpainted water 
pipe. If you fail to do, a component connected to the CAN bus line may be broken.

CAN-C Communication Circuit <Except for RALLIART>

ETACS-ECU

INTERFACE 
CIRCUIT

CAN DRIVE 
CIRCUIT

ASC-ECU

A/T-ECU

ABS-ECU

CVT-ECU

STEERING 
WHEEL SENSOR 
<AFS, ASC>

ENGINE-ECU

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     SI : Silver

CORNER SENSOR/
BACK SENSOR-ECU

DIESEL

:

PETROL

:

1800-PETROL, 2000

:

NOTE

PETROL (EXCEPT SOHC)

:

VEHICLES WITHOUT ASC

:

VEHICLES WITH ASC

:

HEADLAMP 
AUTOMATIC 
LEVELLING-ECU

AS&G-ECU

TROUBLESHOOTING

CONTROLLER AREA NETWORK (CAN)

54C-58

AC709893

AM

Connector: C-03 <LHD>

AC701121BP

Connector: C-03 <RHD>

AC612708 AW

Connector: C-211 <LHD>

AC612716 AX

Connectors: C-211 <RHD>

TROUBLESHOOTING

CONTROLLER AREA NETWORK (CAN)

54C-59

FUNCTION
If the M.U.T.-III cannot communicate with the steer-
ing wheel sensor, this diagnosis result will be set.

TROUBLE JUDGEMENT CONDITIONS
If a communication flag is not set for the steering 
wheel sensor, the ETACS-ECU determines that there 
is a failure.

TROUBLESHOOTING HINTS

• Malfunction of the connector [joint connector 

(CAN2) or steering wheel sensor connector 
improperly connected]

• Malfunction of the wiring harness [open circuit 

between the steering wheel sensor and the joint 
connector (CAN2), power supply circuit to the 
steering wheel sensor]

• Faulty steering wheel sensor

DIAGNOSIS PROCEDURE

STEP 1. Connector check: C-03 joint connector 
(CAN2) and C-211 steering wheel sensor 
connector

CAUTION

The strand end of the twist wire should be within 
10 cm from the connector. For details refer to .

Q: Is the check result normal?

YES : 

Go to Step 2.

NO : 

Repair the defective connector.

STEP 2. Check the wiring harness between C-211 
steering wheel sensor connector and C-03 joint 
connector (CAN2)

CAUTION

Strictly observe the specified wiring harness 
repair procedure. For details refer to .
Disconnect steering wheel sensor connector and 
joint connector (CAN2), and check the following wir-
ing harness for open circuit.
(1) The wiring harness between C-211 steering 

wheel sensor connector terminal No.3 and C-03 
joint connector (CAN2) terminal No.9 <CAN_H>

OK: Continuity exists (2 

Ω or less)

(2) The wiring harness between C-211 steering 

wheel sensor connector terminal No.4 and C-03 
joint connector (CAN2) terminal No.20 <CAN_L>

OK: Continuity exists (2 

Ω or less)

Q: Is the check result normal?

YES : 

Check the power supply circuit of the 

steering wheel sensor. Refer to GROUP 
35C 

− Troubleshooting .

NO : 

Repair the wiring harness.