Mitsubishi Galant 9G. Manual - part 1462

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-258

STEP 1. 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. Refer to "How to connect the 

scan tool 

P.52B-30

."

(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 ).

STEP 2. 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 the DTC set?

YES : Go to Step 3.
NO :  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 ).

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-259

STEP 3. Using scan tool MB991958, read the 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.
(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 DTC B1530, B1531, B1532, B1533, B1534, B1535, 

B1536, B1537, B1538, B1539, B1540, B1541, B1542, 
B1543, B1545 or B1546 set?
YES : Carry out the troubleshooting of the passenger’s seat 

belt switch system, the occupant classification-ECU 
or the occupant classification sensor system (Refer to 

P.52B-310

 <B1530,B1531, B1532, B1533, B1534, 

B1535, B1536, B1537, B1538 or B1539>, 

P.52B-319

 

<B1540,B1541, B1542 or B1543> or 

P.52B-321

 

<B1545 or B1546>).

NO :  Go to Step 4.

STEP 4 Using scan tool MB991958, check actuator test.

• Item No.02: Passenger’s seat belt warning light illumination

Q: Does the passenger’s seat belt warning light illuminate 

or go out normally?
YES : Go to Step 5.
NO :  Replace the passenger’s seat belt warning light 

(Refer to GROUP 52A, Instrument Panel Assembly 

P.52A-3

). Then go to Step 6.

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-260

STEP 5. Check the harness between SRS-ECU connector 
C-121 (terminal No.42) and passenger’s seat belt warning 
light C-07 (terminal No.3).

• Check the passenger’s seat belt warning light output lines 

for open circuit.

NOTE: After inspecting intermediate connector C-22 inspect 
the wiring harness. If intermediate connector C-22 is damaged, 
repair or replace them. Refer to GROUP 00E, Harness Con-
nector Inspection . Then go to Step 6.

Q: Is the check result satisfactory?

YES : Erase the diagnostic trouble code memory, and check 

the diagnostic trouble code. If DTC B1487 sets, 
replace the SRS-ECU (Refer to 

P.52B-365

). Then go 

to Step 6.

NO :  Repair the harness wires. Then go to Step 6.

AC305362

CONNECTOR: C-121

C-121 (Y)

AH

SRS-ECU

C-121
HARNESS SIDE 
CONNECTOR
(REAR VIEW)

42

31

38

27

21

41

28

39

22

30

25

47

36

33

44

34

45

37

48

26

29

23

40

32

43

35

46

24

B

A

AC305233CZ

CONNECTOR: C-07

HARNESS SIDE

AC305233 AI

CONNECTOR: C-22

C-22 (Y)

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-261

STEP 6. 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 B1487 set?

YES : Return to Step 1. 
NO :  The procedure is complete.

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827