Mitsubishi Lancer Evolution X. Manual - part 21

DIAGNOSIS

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CONTROLLER AREA NETWORK (CAN)

54C-109

TRANSAXLE 
ASSEMBLY

ENGINE CONTROL MODULE

CAN-C Communication Circuit <TC-SST>

ETACS-ECU

INTERFACE 
CIRCUIT

CAN DRIVE 
CIRCUIT

JOINT CONNECTOR 
(CAN2)

JOINT CONNECTOR 
(CAN3)

JOINT CONNECTOR 
(CAN4)

SHIFT LEVER

ASC-ECU

STEERING 
WHEEL SENSOR

AWC-ECU

NOTE

: THE TERMINAL NUMBERS DESCRIBED 

IN THE CIRCUIT DIAGRAM AGREE WITH 
THE NUMBERS MARKED ON THE 
TRANSAXLE ASSEMBLY CONNECTOR AND 
HARNESS SIDE CONNECTOR.

DIAGNOSIS

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CONTROLLER AREA NETWORK (CAN)

54C-110

.

FUNCTION

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

.

TROUBLE JUDGMENT CONDITIONS

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

.

TROUBLESHOOTING HINTS

• Malfunction of the connector [joint connector 

(CAN3) or ASC-ECU connector improperly con-
nected]

• Malfunction of the wiring harness [open circuit 

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

• Malfunction of the ASC-ECU

DIAGNOSIS

Required Special Tools:

• MB991223: Harness Set
• MB992006: Extra Fine Probe
• MB991997: ASC Check Harness

STEP 1. Check joint connector (CAN3) C-127 and ASC-ECU 
connector A-05 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 (CAN3) C-127 and ASC-ECU 

connector A-05 in good condition?
YES : Go to Step 2.
NO :  Repair the damaged parts.

AC708948

Connector: A-05

A-05 (B)

AB

AC708951CC

Connector: C-127

DIAGNOSIS

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CONTROLLER AREA NETWORK (CAN)

54C-111

STEP 2. Check the wiring harness between joint connector 
(CAN3) C-127 and ASC-ECU connector A-05 for open 
circuit.

CAUTION

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

P.54C-7

.

(1) Disconnect joint connector (CAN3) C-127 and ASC-ECU 

connector A-05, and check the wiring harness.

(2) Check the wiring harness between joint connector (CAN3) 

C-127 (terminal 6) and ASC-ECU connector A-05 (terminal 
12)

OK: Continuity exists (2 Ω or less)

(3) Check the wiring harness between joint connector (CAN3) 

C-127 (terminal 19) and ASC-ECU connector A-05 
(terminal 13)

OK: Continuity exists (2 Ω or less)

Q: Is the wiring harness between joint connector (CAN3) 

C-127 and ASC-ECU connector A-05 in good condition?
YES : Check the power supply circuit of the ASC-ECU. 

Refer to GROUP 35C, Troubleshooting 

P.35C-258

.

NO :  Repair the wiring harness between joint connector 

(CAN3) C-127 and ASC-ECU connector A-05.

AC709707

Harness side: C-127

BN

Harness side: A-05

TEST 
HARNESS

TEST 
HARNESS

AC709707

Harness side: C-127

BO

Harness side: A-05

TEST 
HARNESS

TEST HARNESS

DIAGNOSIS

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CONTROLLER AREA NETWORK (CAN)

54C-112

DIAGNOSTIC ITEM 10: Diagnose when the scan tool cannot receive the data sent by ECM.

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-C Communication Circuit <M/T>

ETACS-ECU

INTERFACE 
CIRCUIT

CAN DRIVE 
CIRCUIT

JOINT CONNECTOR 
(CAN2)

JOINT CONNECTOR 
(CAN3)

ASC-ECU

STEERING 
WHEEL SENSOR

AWC-ECU

ENGINE CONTROL 
MODULE