Mitsubishi Galant 9G. Manual - part 1454

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-226

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

Q: Is DTC B1472 set?

YES : Go to Step 3.
NO :  Go to Step 6.

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-227

STEP 3. Check the driver's seat belt pre-tensioner. (Using 
scan tool MB991958, read the diagnostic trouble code.)
(1) Disconnect the negative battery terminal.
(2) Disconnect driver's seat belt pre-tensioner connector D-21. 

Use a flat-tipped screwdriver to unlock the locking button at 
the harness side connector by withdrawing it toward you in 
two stages, and then disconnect the connector.

(3) Connect special tool MB991865 to special tool MB991884.
(4) Connect special tool MB991884 to the D-21 harness side 

connector.

(5) Connect the negative battery terminal.
(6) Erase diagnostic trouble code memory, and check the 

diagnostic trouble code.

Q: Is DTC B1472 set?

YES : Go to Step 4.
NO :  Replace the driver's seat belt pre-tensioner (Refer to 

P.52B-380

). Then go to Step 6.

AC306920AC

CONNECTOR: D-21

D-21 (B)

FOWARD

CENTER
PILLAR

HARNESS SIDE
CONNECTOR
(FRONT VIEW)

2 1

AC103556 AT

LOCKING BUTTON

FLAT-TIP SCREW
DRIVER

D-21 HARNESS 
SIDE CONNECTOR

D-21 DRIVER'S 
SEAT BELT
PRE-TENSIONER
CONNECTOR

MB991884
MB991885

AC103283AO

MB991865
(DUMMY RESISTOR : 3

Ω

)

MB991884
(RESISTOR 
HARNESS)

D-21  HARNESS SIDE 
CONNECTOR

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-228

STEP 4. Check the driver's seat belt pre-tensioner circuit. 
Measure the voltage at the SRS-ECU connector C-122.
(1) Disconnect SRS-ECU connector C-122.

(2) Disconnect driver's seat belt pre-tensioner connector D-21. 

Use a flat-tipped screwdriver to unlock the locking button at 
the harness side connector by withdrawing it toward you in 
two stages, and then disconnect the connector.

(3) Turn the ignition switch to the "ON" position.

CAUTION

Do not insert a test probe into the terminal from its front 
side directly, as the connector contact pressure may be 
weakened.
(4) Measure the voltage between C-122 harness side 

connector terminals 7, 8 and body ground.
Voltage should measure 0 volt.

Q: Is the measured voltage within the specified range?

YES : Erase the diagnostic trouble code memory, and check 

the diagnostic trouble code. If DTC B1472 sets, 
replace the SRS-ECU (Refer to 

P.52B-105

). Then go 

to Step 6.

NO :  Go to Step 5.

AC305362

CONNECTOR: C-122

C-122 (Y)

AI

SRS-ECU

C-122 
Harness side
connector 
(rear view)

A

B

18

10

15

7

13

5

14

6

16

8

17

9

19

11

20

12

1 2

3 4

AC306920AC

CONNECTOR: D-21

D-21 (B)

FOWARD

CENTER
PILLAR

HARNESS SIDE
CONNECTOR
(FRONT VIEW)

2 1

AC103556 AT

LOCKING BUTTON

FLAT-TIP SCREW
DRIVER

D-21 HARNESS 
SIDE CONNECTOR

D-21 DRIVER'S 
SEAT BELT
PRE-TENSIONER
CONNECTOR

AC308182

A

B

18

10

15

7

13

5

14

6

16

8

17

9

19

11

20

12

1 2

3 4

AB

C-122 HARNESS SIDE
CONNECTOR
(REAR VIEW)

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-229

STEP 5. Check the harness wires for short circuit to power 
supply between SRS-ECU connector C-122 (terminal No.7 
and 8) and driver's seat belt pre-tensioner connector D-21 
(terminal No.1 and 2).
Q: Are the harness wires between SRS-ECU connector 

C-122 (terminal No.7 and 8). and driver's seat belt 
pre-tensioner connector D-21 (terminal No.1 and 2) in 
good condition?
YES : Go to Step 6.
NO :  Replace the harness wires between SRS-ECU 

connector C-122 and driver's seat belt pre-tensioner 
connector D-21. Then go to Step 6.

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 B1472 set?

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

AC305362

CONNECTOR: C-122

C-122 (Y)

AI

SRS-ECU

C-122 
Harness side
connector 
(rear view)

A

B

18

10

15

7

13

5

14

6

16

8

17

9

19

11

20

12

1 2

3 4

AC306920AC

CONNECTOR: D-21

D-21 (B)

FOWARD

CENTER
PILLAR

HARNESS SIDE
CONNECTOR
(FRONT VIEW)

2 1

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827