Mitsubishi 380. Manual — part 14

DIAGNOSTIC TROUBLE CODE PROCEDURES

SIMPLIFIED WIRING SYSTEM (SWS)

54B-53

STEP 5. Recheck for diagnostic trouble code.
Check again if the DTC is set.
(1) Turn the ignition switch to the "ON" position.
(2) Check if the DTC is set.
(3) Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is the DTC set?

YES : Replace the ETACS-ECU. On completion, verify that

the DTC is not reset.

NO : A poor connection, open circuit or other intermittent

malfunction is present in the CAN bus lines between
the multi center display and the ETACS-ECU (Refer
to GROUP 00, How to Cope with Intermittent
Malfunction

P.00-14

).

DTC 021 (U1128): Failure Information on Combination Meter.

CAUTION

If DTC 021 (U1128) is set in the ETACS-ECU,
always diagnose the CAN main bus line.

CAUTION

Whenever the ECU is replaced, ensure that the
communication circuit is normal.

CAUTION

The combination meter- related DTC may be set
when DTC 021 (U1128) is set. (For details refer
to GROUP 00, Affiliated DTC Reference Table

P.00-17

.) Diagnose the combination meter first

when the combination meter- related DTC is set.

.

TROUBLE JUDGMENT

The ETACS-ECU receives combination
meter-related signal from the combination meter via
the CAN bus lines. If a fail-safe related data is con-
tained in the signal from the combination meter,
DTC 021 (U1128) will be stored.

.

TECHNICAL DESCRIPTION (COMMENT)

Current trouble

• The wiring harness wire or connectors may have

loose, corroded, or damage terminals, or termi-
nals pushed back in the connector, the Engine-
ECU, the combination meter or the ETACS-ECU
may be defective.

• Refer to circuit diagrams GROUP-

90

• Refer to configuration diagrams GROUP-

80

00DB076A

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

DIAGNOSTIC TROUBLE CODE PROCEDURES

SIMPLIFIED WIRING SYSTEM (SWS)

54B-54

Past trouble

• If DTC 021 (U1128) is stored as a past trouble,

carry out diagnosis with particular emphasis on
wiring and connector(s) in the CAN bus line
between the combination meter and the
ETACS-ECU, and the power supply system to the
combination meter. For diagnosis procedures,
refer to "How to cope with past trouble" (Refer to
GROUP 00, How to treat past trouble

P.00-16

).

NOTE: You cannot find a past trouble, by the
MUT-III CAN bus diagnostics even if there is a
failure in CAN bus lines. In this case, refer to
GROUP 00, How to Cope with Intermittent Mal-
function

P.00-14

and check the CAN bus lines.

You can narrow down the possible cause of the
trouble by referring to the DTC, which is set
regarding the CAN communication-linked ECUs
(Refer to GROUP 54C, CAN Bus Line Diagnos-
tics

P.54C-6

).

.

TROUBLESHOOTING HINTS

• The ETACS-ECU may be defective

DIAGNOSIS

Required Special Tools:

• MB991223: Harness Set

• MB991958: DIAGNOSTIC TOOL (MUT-III Sub Assembly)

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

• MB991827: MUT-III USB Cable

• MB991910: MUT-III Main Harness A

STEP 1. Using diagnostic tool MB991958, diagnose the
CAN bus line.

CAUTION

To prevent damage to diagnostic tool MB991958, always
turn the ignition switch to the "LOCK" (OFF) position
before connecting or disconnecting diagnostic tool
MB991958.
(1) Connect diagnostic tool MB991958. Refer to "How to

connect SWS monitor

P.54B-13

."

(2) Turn the ignition switch to the "ON" position.
(3) Diagnose the CAN bus line.
(4) Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is the CAN bus line found to be normal?

YES : Go to Step 2.
NO : Repair the CAN bus line (Refer to GROUP 54C,

Diagnosis

P.54C-5

).

00DB076A

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

DIAGNOSTIC TROUBLE CODE PROCEDURES

SIMPLIFIED WIRING SYSTEM (SWS)

54B-55

STEP 2. Using diagnostic tool MB991958, read the Engine
ECU and A/T ECU diagnostic trouble code.
Check whether engine and automatic transaxle DTCs are set
or not.
(1) Turn the ignition switch to the "ON" position.
(2) Check for engine and automatic transaxle DTCs.
(3) Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is the DTC set?

YES : Diagnose the Engine ECU (Refer to GROUP 13A,

Diagnosis

P.13A-5

), and GROUP 23A Automatic

transmission ECU, Diagnosis

P.23A-12

.

NO : Go to Step 3.

STEP 3. Using diagnostic tool MB991958, read the
combination meter diagnostic trouble code.
Check whether the combination meter-related DTC is set.
(1) Turn the ignition switch to the "ON" position.
(2) Check whether the combination meter-related DTC is set.
(3) Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is the DTC set?

YES : Diagnose the combination meter (Refer to GROUP

54A, Diagnosis

P.54A-46

).

NO : Go to Step 4.

00DB076A

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

00DB076A

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

DIAGNOSTIC TROUBLE CODE PROCEDURES

SIMPLIFIED WIRING SYSTEM (SWS)

54B-56

STEP 4. Recheck for diagnostic trouble code.
Check again if the DTC is set.
(1) Turn the ignition switch to the "ON" position.
(2) Check if the DTC is set.
(3) Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is the DTC set?

YES : Replace the ETACS-ECU. On completion, verify that

the DTC is not reset.

NO : There is an intermittent malfunction such as poor

engaged connector(s) or open circuit (Refer to
GROUP 00, How to Cope with Intermittent
Malfunction

P.00-14

).

00DB076A

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827