Mitsubishi Evolution X. Manual - part 1099

DIAGNOSIS

TSB Revision

CONTROLLER AREA NETWORK (CAN)

54C-31

STEP 6. Using scan tool MB991958, diagnose the CAN bus 
line.

CAUTION

To prevent damage to scan tool MB991958, always turn the 
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991958.
(1) Connect scan tool MB991958 to the data link connector.
(2) Turn the ignition switch to the "ON" position.

(3) Diagnose CAN bus lines, and check if the scan tool screen 

is as shown in the illustration.

Q: Does the scan tool screen correspond to the 

illustration?
YES : The trouble can be an intermittent malfunction (Refer 

to GROUP 00, How to use 
Troubleshooting/inspection Service Points 

− How to 

Cope with Intermittent Malfunction 

P.00-15

).

NO :  Replace the ETACS-ECU.

AC608435

Data link connector

MB991827

MB991824

MB991910

AB

AC709542 AB

: Red section on screen

M.U.T.

J/C (3)

SAS

J/C (2)

KOS/WCM

SRS

A/C

AUDIO

MMCS

Sat Radio

HFM

OCM

METER

ASC

ENGINE

J/C (1)

ETACS

<M/T>

S-AWC

AC709543 AB

: Red section on screen

M.U.T.

J/C (3)

SAS

J/C (2)

KOS/WCM

SRS

A/C

AUDIO

MMCS

Sat Radio

HFM

OCM

METER

ASC

LEVER

ENGINE

J/C (1)

ETACS

<TC-SST>

S-AWC

TC-SST

J/C (4)

DIAGNOSIS

TSB Revision

CONTROLLER AREA NETWORK (CAN)

54C-32

DIAGNOSTIC ITEM 2: Malfunction of the ETACS-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, a component con-
nected to the CAN bus line may be broken.

.

FUNCTION

When the CAN bus diagnosis is carried out, the scan 
tool sets communication "OK" flags in the patch 
between the ETACS-ECU and active other ECUs. If 
a commutation "OK" flag is not set for the ECUs 
other than the ETACS-ECU, this diagnosis result will 
be set.

.

TROUBLE JUDGEMENT CONDITIONS

If no communication flags are set for the ECUs (on 
the CAN-B or CAN-C lines) other than the 
ETACS-ECU, the ETACS-ECU determines that there 
is a failure.

.

TROUBLESHOOTING HINT

Malfunction of the ETACS-ECU

DIAGNOSIS

Required Special Tools:

• MB991958: Scan Tool (M.U.T.-III Sub Assembly)

• MB991824: Vehicle Communication Interface (V.C.I.)

• MB991827: M.U.T.-III USB Cable

• MB991910: M.U.T.-III Main Harness A

Recheck for other system diagnostic trouble code. 

CAUTION

To prevent damage to scan tool MB991958, always turn the 
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991958.
Check whether ETACS-ECU-related DTC is set.
(1) Connect scan tool MB991958 to the data link connector.
(2) Turn the ignition switch to the "ON" position.
(3) Check if the DTC is set.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the DTC set?

YES (The DTC other than the U code is set.) : 

Troubleshoot the ETACS-ECU. Refer to GROUP 54A, 
ETACS-ECU 

P.54A-582

.

YES (Only U-code DTC is set.) : Check the power supply 

circuit of the ETACS-ECU. Refer to GROUP 54A, 
ETACS-ECU 

P.54A-635

.

NO (The DTC is not set.) : Check the power supply circuit 

of the ETACS-ECU. Refer to GROUP 54A, 
ETACS-ECU 

P.54A-635

.

AC608435

Data link connector

MB991827

MB991824

MB991910

AB

DIAGNOSIS

TSB Revision

CONTROLLER AREA NETWORK (CAN)

54C-33

DIAGNOSTIC ITEM 3: Abnormal short between the CAN-C bus lines.

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

S-AWC-ECU

ENGINE
CONTROL
MODULE

DIAGNOSIS

TSB Revision

CONTROLLER AREA NETWORK (CAN)

54C-34

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

S-AWC-ECU

NOTE

: THE TERMINAL NUMBERS DESCRIBED 

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