Mitsubishi Lancer (4A9 engine). Manual — part 263

TROUBLESHOOTING

CONTROLLER AREA NETWORK (CAN)

54C-76

Diagnosis Item 12: Diagnose when the M.U.T.-III cannot receive the data sent by engine-ECU

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-77

AC800715

Connectors: B-09, B-40

BC

B-09 (GR),
B-40 (B)

ACB02645

AH

Connector: C-124 <LHD>

C-124 (GR)

ACB02647

AE

C-124 (GR)

Connector: C-124 <RHD>

TROUBLESHOOTING

CONTROLLER AREA NETWORK (CAN)

54C-78

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

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

TROUBLESHOOTING HINTS

• Malfunction of the connector [joint connector

(CAN3) and engine-ECU connector improperly
connected]

• Malfunction of the wiring harness [open circuit

between the engine-ECU and the joint connector
(CAN3) power supply circuit to the engine-ECU]

• Malfunction of the engine-ECU

DIAGNOSIS PROCEDURE

STEP 1. Connector check: B-09 <Petrol> or B-40
<Diesel> engine-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 B-09
<Petrol> or B-40 <Diesel> engine-ECU connector
and C-124 joint connector (CAN3)

CAUTION

Strictly observe the specified wiring harness
repair procedure. For details refer to .
Disconnect engine-ECU connector and joint connec-
tor (CAN3) and check the following wiring harness
for open circuit.
(1) The wiring harness between B-09 <Petrol> or B-

40 <Diesel> engine-ECU connector terminal
No.90 <Petrol> or 108 <Diesel> and C-124 joint
connector (CAN3) terminal No.4 <CAN_H>

OK: Continuity exists (2

Ω or less)

(2) The wiring harness between B-09 <Petrol> or B-

40 <Diesel> engine-ECU connector terminal
No.91 <Petrol> or 109 <Diesel> and C-124 joint
connector (CAN3) terminal No.15 <CAN_L>

OK: Continuity exists (2

Ω or less)

Q: Is the check result normal?

YES :

Check the power supply circuit of the

engine-ECU. Refer to GROUP 13A

−

Troubleshooting <1600>, GROUP 13B

−

Troubleshooting <Petrol (1800-DOHC),
2000>, GROUP 13C

− Troubleshooting

<Diesel> or GROUP 13F

− Troubleshooting

<1800-SOHC>

NO :

Repair the wiring harness.

TROUBLESHOOTING

CONTROLLER AREA NETWORK (CAN)

54C-79

Diagnosis Item 13: Diagnose the lines between the ETACS-ECU and joint connector (CAN2)

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.