Mitsubishi Lancer (4A9 engine). Manual - part 261

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-68

ACA00830AC

Connector: C-14 <LHD>

C-14

ACB02647

AF

C-124 (GR)

C-14

Connectors: C-14, C-124 <RHD>

ACB02645

AH

Connector: C-124 <LHD>

C-124 (GR)

TROUBLESHOOTING

CONTROLLER AREA NETWORK (CAN)

54C-69

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 con-
nected to the CAN bus line may be broken.
FUNCTION
If the M.U.T.-III cannot communicate with the head-
lamp automatic levelling-ECU, this diagnosis result 
will be set.

TROUBLE JUDGEMENT CONDITIONS
If a communication flag is not set for the headlamp 
automatic levelling-ECU, the ETACS-ECU deter-
mines that there is a failure.

TROUBLESHOOTING HINTS

• Malfunction of the connector [joint connector 

(CAN3) or headlamp automatic levelling-ECU 
improperly connected]

• Malfunction of the wiring harness [open circuit 

between the headlamp automatic levelling-ECU 
and the joint connector (CAN3), power supply cir-
cuit to the headlamp automatic levelling-ECU]

• Malfunction of the headlamp automatic levelling-

ECU

DIAGNOSIS PROCEDURE

STEP 1. Connector check: C-14 headlamp 
automatic levelling-ECU connector and C-124 
joint connector (CAN3)

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-14 
headlamp automatic levelling-ECU connector 
and C-124 joint connector (CAN3)

CAUTION

Strictly observe the specified wiring harness 
repair procedure. For details refer to .
Disconnect headlamp automatic levelling-ECU con-
nector and joint connector (CAN3), and check the fol-
lowing wiring harness for open circuit.
(1) The wiring harness between C-14 headlamp 

automatic levelling-ECU connector terminal 
No.23 and C-124 joint connector (CAN3) terminal 
No.8 <Diesel> or 7 <Petrol> <CAN_H>

OK: Continuity exists (2 

Ω or less)

(2) The wiring harness between C-14 headlamp 

automatic levelling-ECU connector terminal 
No.22 and C-124 joint connector (CAN3) terminal 
No.19 <Diesel> or 18 <Petrol> <CAN_L>

OK: Continuity exists (2 

Ω or less)

Q: Is the check result normal?

YES : 

Check the power supply circuit of the 

headlamp automatic levelling-ECU. Refer to 
GROUP 54A 

− Headlamp − 

Troubleshooting .

NO : 

Repair the wiring harness.

TROUBLESHOOTING

CONTROLLER AREA NETWORK (CAN)

54C-70

Diagnosis Item 10: Diagnose when the M.U.T.-III cannot receive the data sent by electric power 
steering-ECU <vehicles with electric power steering>

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-71