Mitsubishi Lancer Evolution X. Manual - part 29

DIAGNOSIS

TSB Revision

CONTROLLER AREA NETWORK (CAN)

54C-141

DIAGNOSTIC ITEM 18: Diagnose when the scan tool cannot receive the data sent by occupant 
classification-ECU.

CAUTION

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

CAN-B Communication Circuit

ETACS-ECU

INTERFACE 
CIRCUIT

INTERFACE 
CIRCUIT

CAN DRIVE 
CIRCUIT

HANDS FREE 
MODULE

OCCUPANT 
CLASSIFICATION-
ECU

SATELLITE 
RADIO TUNER

RADIO AND CD
PLAYER

NOTE

VEHICLES WITHOUT MITSUBISHI MULTI-COMMUNICATION SYSTEM (MMCS)
VEHICLES WITH MITSUBISHI MULTI-COMMUNICATION SYSTEM (MMCS)

CAN 
TRANSCEIVER 
CIRCUIT

CAN BOX UNIT

JOINT CONNECTOR 
(CAN1)

FRONT SEAT 
ASSEMBLY (LH)

DIAGNOSIS

TSB Revision

CONTROLLER AREA NETWORK (CAN)

54C-142

.

FUNCTION

If the scan tool MB991958 cannot communicate with 
the occupant classification-ECU, this diagnosis result 
will be set.

.

TROUBLE JUDGMENT CONDITIONS

If a communication flag is not set for the occupant 
classification-ECU, the ETACS-ECU determines that 
there is a failure.

.

TROUBLESHOOTING HINTS

• Malfunction of the connector [joint connector 

(CAN1), occupant classification-ECU connector 
improperly connected]

• Malfunction of the wiring harness [open circuit 

between the occupant classification-ECU con-
nector and the joint connector (CAN1), power 
supply circuit to the occupant classification-ECU]

• Malfunction of the occupant classification-ECU

DIAGNOSIS

Required Special Tools:

• MB991223: Harness Set
• MB992006: Extra Fine Probe

STEP 1. Check joint connector (CAN1) C-105, occupant 
classification-ECU connector D-39, D-39-2 and 
intermediate connector C-41 for loose, corroded or 
damaged terminals, or terminals pushed back in the 
connector.

CAUTION

The strand end of the twisted wire should be within 10 cm 
(4 inches) from the connector. For details refer to 

P.54C-7

.

Q: Are joint connector (CAN1) C-105, occupant 

classification-ECU connector D-39, D-39-2 and 
intermediate connector C-41 in good condition?
YES : Go to Step 2.
NO :  Repair the damaged parts.

AC708950CA

C-41

C-105

Connectors: C-41, C-105

AC708954 AV

Connectors: D-39, D-39-2

D-39, 
D-39-2

DIAGNOSIS

TSB Revision

CONTROLLER AREA NETWORK (CAN)

54C-143

STEP 2. Check the wiring harness between joint connector 
(CAN1) C-105 and occupant classification-ECU connector 
D-39-2 for open circuit.

CAUTION

Strictly observe the specified wiring harness repair proce-
dure. For details refer to 

P.54C-7

.

(1) Disconnect joint connector (CAN1) C-105 and occupant 

classification-ECU connector D-39-2, and check the wiring 
harness.

(2) Check the wiring harness between joint connector (CAN1) 

C-105 (terminal 11) and occupant classification-ECU 
connector D-39-2 (terminal 24)

OK: Continuity exists (2 Ω or less)

(3) Check the wiring harness between joint connector (CAN1) 

C-105 (terminal 24) and occupant classification-ECU 
connector D-39-2 (terminal 25)

OK: Continuity exists (2 Ω or less)

Q: Is the wiring harness between joint connector (CAN1) 

C-105 and occupant classification-ECU connector 
D-39-2 in good condition?
YES : Check the power supply circuit of the occupant 

classification-ECU. Refer to GROUP 52B, SRS air 
bag Diagnosis 

P.52B-383

.

NO :  Repair the wiring harness between joint connector 

(CAN1) C-105 and occupant classification-ECU 
connector D-39-2.

AC709707

AC709707 CB

Harness side: C-105

Harness side: D-39-2

TEST HARNESS

TEST HARNESS

AC709707 CC

Harness side: C-105

Harness side: D-39-2

TEST HARNESS

TEST 
HARNESS

DIAGNOSIS

TSB Revision

CONTROLLER AREA NETWORK (CAN)

54C-144

DIAGNOSTIC ITEM 19: Diagnose when the scan tool cannot receive the data sent by A/C-ECU 
<vehicles with A/C> or heater control unit <vehicles without A/C>.

CAUTION

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

CAN-B Communication Circuit

ETACS-ECU

INTERFACE 
CIRCUIT

CAN DRIVE 
CIRCUIT

A/C-ECU

COMBINATION 
METER

SRS-ECU

WIRELESS 
CONTROL 
MODULE

KOS-ECU

NOTE

VEHICLES WITH WCM
VEHICLES WITH KOS

CAN DRIVE 
CIRCUIT

CAN DRIVE 
CIRCUIT

CAN DRIVE 
CIRCUIT

JOINT CONNECTOR 
(CAN1)