Mitsubishi Lancer (4A9 engine). Manual - part 266

ACB02645

AM

C-04 (GR)

C-23

Connectors: C-04, C-23 <LHD>

ACB02647

AI

C-04 (GR)

Connectors: C-04, C-23 <RHD>

C-23

TROUBLESHOOTING

CONTROLLER AREA NETWORK (CAN)

54C-88

FUNCTION
If the M.U.T.-III cannot communicate with the KOS-
ECU, this diagnosis result will be set.

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

TROUBLESHOOTING HINTS

• Malfunction of the connector [joint connector 

(CAN1) or KOS-ECU connector improperly con-
nected]

• Malfunction of the wiring harness [open circuit 

between the KOS-ECU connector and the joint 
connector (CAN1), or power supply circuit to the 
KOS-ECU]

• Malfunction of the KOS-ECU

DIAGNOSIS PROCEDURE

STEP 1. Connector check: C-04 joint connector 
(CAN1) and C-23 KOS-ECU 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-23 
KOS-ECU connector and C-04 joint connector 
(CAN1)

CAUTION

Strictly observe the specified wiring harness 
repair procedure. For details refer to .
Disconnect KOS-ECU connector and joint connector 
(CAN1), and check the following wiring harness for 
open circuit
(1) The wiring harness between C-23 KOS-ECU 

connector terminal No.1 and C-04 joint connector 
(CAN1) terminal No.5 <CAN_H>

OK: Continuity exists (2 

Ω or less)

(2) The wiring harness between C-23 KOS-ECU 

connector terminal No.2 and C-04 joint connector 
(CAN1) terminal No.16 <CAN_L>

OK: Continuity exists (2 

Ω or less)

Q: Is the check result normal?

YES : 

Check the power supply circuit of the KOS-

ECU. Refer to GROUP 42B 

− 

Troubleshooting .

NO : 

Repair the wiring harness.

TROUBLESHOOTING

CONTROLLER AREA NETWORK (CAN)

54C-89

Diagnosis Item 16: Diagnose when the M.U.T.-III cannot receive the data sent by WCM <vehicles 
without KOS>

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-B Communication Circuit

ETACS-ECU

INTERFACE 
CIRCUIT

CAN DRIVE 
CIRCUIT

SRS-ECU

CPU

WCM

CAN BOX UNIT

KOS-ECU

CAN 
TRANSCEIVER 
CIRCUIT

CAN DRIVE 
CIRCUIT

CAN DRIVE 
CIRCUIT

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

RADIO AND 
CD PLAYER

CAN 
TRANSCEIVER 
CIRCUIT

INTERFACE 
CIRCUIT

VEHICLES WITHOUT A/C

:

VEHICLES WITH A/C

:

VEHICLES WITH KOS

:

NOTE

VEHICLES WITH WCM

:

VEHICLES WITH RADIO AND CD PLAYER

:

VEHICLES WITHOUT AUDIO

:

VEHICLES WITH MMCS

:

COMBINATION 
METER

HEATER CONTROL
PANEL
A/C-ECU

SPARE 
CONNECTOR 
(FOR AUDIO)

TROUBLESHOOTING

CONTROLLER AREA NETWORK (CAN)

54C-90

ACB02645

AN

C-04 (GR)

Connectors: C-04, C-06 <LHD>

C-06

ACB02647

AJ

C-04 (GR)

C-06

Connectors: C-04, C-06 <RHD>

TROUBLESHOOTING

CONTROLLER AREA NETWORK (CAN)

54C-91

FUNCTION
If the M.U.T.-III cannot communicate with the WCM, 
this diagnosis result will be set.

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

TROUBLESHOOTING HINTS

• Malfunction of the connector [joint connector 

(CAN1) or WCM connector improperly con-
nected]

• Malfunction of the wiring harness [open circuit 

between the WCM connector and the joint con-
nector (CAN1), or power supply circuit to the 
WCM]

• Malfunction of the WCM

DIAGNOSIS PROCEDURE

STEP 1. Connector check: C-04 joint connector 
(CAN1) and C-06 WCM 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-06 
WCM connector and C-04 joint connector (CAN1)

CAUTION

Strictly observe the specified wiring harness 
repair procedure. For details refer to .
Disconnect WCM connector and joint connector 
(CAN1), and check the following wiring harness for 
open circuit
(1) The wiring harness between C-06 WCM 

connector terminal No.11 and C-04 joint 
connector (CAN1) terminal No.7 <CAN_H>

OK: Continuity exists (2 

Ω or less)

(2) The wiring harness between C-06 WCM 

connector terminal No.10 and C-04 joint 
connector (CAN1) terminal No.18 <CAN_L>

OK: Continuity exists (2 

Ω or less)

Q: Is the check result normal?

YES : 

Check the power supply circuit of the WCM. 

Refer to GROUP 42C 

−WCM− 

Troubleshooting .

NO : 

Repair the wiring harness.