Mitsubishi 380. Manual — part 822

SRS AIR BAG DIAGNOSIS

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-212

STEP 3. Using diagnostic tool MB991958, read the
diagnostic trouble code.

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.
Check that the DTC except B1547 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 "LOOK (OFF)" position.

Q: Is the DTC set?

YES : Carry out the troubleshooting according to a set DTC.

Refer to

P.52B-21

.

NO : Go to Step 4.

STEP 4. Recheck for diagnostic trouble code.
Check again if the DTC is set.
(1) Erase the DTC.
(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 DTC B1547 set?

YES : Replace the SRS-ECU (Refer to

P.52B-234

).

NO : The procedure is complete.

00DB076A

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

00DB076A

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

SRS AIR BAG DIAGNOSIS

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-213

DTC U1073: Bus Off

CAUTION

If DTC U1073 is set in the SRS-ECU, diagnose the
CAN main bus line.

CAUTION

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

.

TROUBLE JUDGMENT

DTC U1073 will be stored when the SRS-ECU
ceases CAN communication (bus off) and then
resumes the communication when the ignition switch
is turned to the "LOCK" (OFF) position.

.

TECHNICAL DESCRIPTION (COMMENT)

The wiring harness wire or connectors may have
loose, corroded, or damage terminals, or terminals
pushed back in the connector, or the SRS-ECU may
be defective.

.

TROUBLESHOOTING HINTS

• Defective connector(s) or wiring harness

• Malfunction of the SRS-ECU

• Refer to circuit diagrams GROUP-

90

• Refer to configuration diagrams GROUP-

80

DIAGNOSIS

Required Special Tools:

• 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 (Vehicles with CAN

communication system)

SRS AIR BAG DIAGNOSIS

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-214

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

CAUTION

To prevent damage to diagnostic tool (MUT-III), always turn
the ignition switch to the "LOCK" (OFF) position before
connecting or disconnecting diagnostic tool (MUT-III).
(1) Connect diagnostic tool MB991958 to the data link

connector.

(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 lines (Refer to GROUP 54C,

precautions on how to repair the can bus lines ).

STEP 2. Recheck for diagnostic trouble code.
Check again if the DTC is set.
(1) Connect diagnostic 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 check result satisfactory?

YES : There is an intermittent malfunction such as poor

engaged connector(s) or open circuit (Refer to
GROUP 00, How to Use Troubleshooting/Inspection
Service Points

− How to Cope with Intermittent

Malfunctions ).

NO : Replace the A/C-ECU. On completion, check that the

DTC is not reset.

00DB076A

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

00DB076A

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

SRS AIR BAG DIAGNOSIS

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-215

TROUBLE SYMPTOM CHART

M1524003400495

CAUTION

During diagnosis, a DTC code associated with
another system may be set when the ignition
switch is turned on with connector(s) discon-
nected. After completing the repair, confirm all
systems for DTC code(s). If DTC code(s) are set,
erase them all.

SYMPTOM

INSPECTION PROCEDURE NO. REFERENCE PAGE

Communication between the diagnostic tool
and the SRS-ECU is not possible.

1

P.52B-216

Power supply circuit system

2

P.52B-217

When the ignition key is turned to the "ON"
position (engine stopped), the SRS warning
light does not illuminate.

3

P.52B-220

After the ignition key is turned to the "ON"
position, the SRS warning light does not go off
within approximately seven seconds.

4

P.52B-220