Mitsubishi Galant 9G. Manual - part 1414

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-66

STEP 3. Check the driver's air bag module. (Using scan 
tool MB991958, read the diagnostic trouble code.)
(1) Disconnect the negative battery terminal.
(2) Slide the outer housing of the driver’ s air bag module 

connector C-305 in the arrow direction shown, and 
disconnect the connector.

(3) Connect special tool MB991865 to special tool MB991866.

CAUTION

Do not insert a test probe into the terminal from its front 
side directly, as the connector contact pressure may be 
weakened.
(4) Insert special tool MB991866 into clock spring side air bag 

module connector C-305 (terminal No.1 and 2 <1st squib> 
or terminal No.3 and 4 <2nd squib>) by backprobing.

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

diagnostic trouble code.

Q:  Is DTC B1403 <1st squib> or B1483 <2nd squib> set?

YES : Go to Step 4.
NO :  Replace the driver's air bag module (Refer to 

P.52B-368

). Then go to Step 7. 

AC306561AC

OUTER HOUSING OF THE DRIVER'S 
AIR BAG MODULE CONNECTOR C-305

AC306758 AB

C-305 AIR BAG
MODULE
CONNECTOR

MB991865
(DUMMY RESISTOR : 3

Ω)

MB991866 (RESISTOR 
HARNESS)

(REAR VIEW

)

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-67

STEP 4. Check the clock spring. (Using scan tool 
MB991958, read the diagnostic trouble code.)
(1) Disconnect the negative battery terminal.
(2) Disconnect the clock spring connector C-307.

(3) Connect special tool MB991865 to special tool MB991866.

CAUTION

Do not insert a test probe into the terminal from its front 
side directly, as the connector contact pressure may be 
weakened.
(4) Insert special tool MB991866 into clock spring harness side 

connector C-307 (terminal No.13 and 14 <1st squib> or 
terminal No. 11 and 12 <2nd squib>) by backprobing.

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

diagnostic trouble code.

Q: Is DTC B1403 <1st squib> or B1483 <2nd squib> set?

YES : Go to Step 5.
NO :  Replace the clock spring (Refer to 

P.52B-368

). Then 

go to Step 7. 

AC305235AK

C-307 (Y)

CONNECTOR: C-307

C-307 HARNESS
SIDE CONNECTOR

CLOCK
SPRING

11

12

13

14

AC306767

C-307 CLOCK SPRING
CONNECTOR

AB

MB991865
(DUMMY RESISTOR : 3

Ω)

MB991866 (RESISTOR 
HARNESS)

1112

14

13

(REAR VIEW)

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-68

STEP 5. Check the driver’s air bag module circuit. Measure 
the resistance at the SRS-ECU connector C-121.
(1) Disconnect SRS-ECU connector C-121.

DANGER

To prevent the air bag from deploying unintentionally, 
disconnect the clock spring connector C-307 to short 
the squib circuit.

(2) Disconnect the clock spring connector C-307.

CAUTION

Do not insert a test probe into the terminal from its front 
side directly, as the connector contact pressure may be 
weakened.
(3) Check for continuity between C-121 harness side connector 

terminals 36 and 37 <1st squib> or 33 and 34 <2nd squib> 
and body ground.
It should be open circuit.

Q: Does continuity exist?

YES : Erase the diagnostic trouble code memory, and check 

the diagnostic trouble code. If DTC B1403 <1st 
squib> or B1483 <2nd squib> sets, replace the 
SRS-ECU (Refer to 

P.52B-365

). Then go to Step 6. 

NO :  Go to Step 7.

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

AC305235AK

C-307 (Y)

CONNECTOR: C-307

C-307 HARNESS
SIDE CONNECTOR

CLOCK
SPRING

11

12

13

14

AC301591

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

C-121 HARNESS SIDE 
CONNECTOR (REAR VIEW)

<1ST SQUIB>

AC

AC308149

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

C-121 HARNESS SIDE 
CONNECTOR (REAR VIEW)

<2ND SQUIB>

AB

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-69

STEP 6. Check the harness for short circuit to ground 
between SRS-ECU connector C-121 (terminal No.36 and 37 
<1st squib> or terminal No.33 and 34 <2nd squib>) and 
clock spring connector C-307 (terminal No.13 and 14 or 
terminal No. 11 and 12 <2nd squib>).

NOTE: After inspecting intermediate connector C-22 inspect 
the wiring harness. If the intermediate connector C-22 is dam-
aged, repair or replace it.

Q: Are the harness wires between SRS-ECU connector 

C-121 (terminal No.36 and 37 <1st squib> or terminal 
No.33 and 34 <2nd squib>) and clock spring connector 
C-307 (terminal No.13 and 14 or terminal No. 11 and 12 
<2nd squib>) in good condition?
YES : Go to Step 7.
NO :  Replace the harness wires between SRS-ECU 

connector C-121 and clock spring connector C-307. 
Then go to Step 7.

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

AC305235AK

C-307 (Y)

CONNECTOR: C-307

C-307 HARNESS
SIDE CONNECTOR

CLOCK
SPRING

11

12

13

14

AC305233

C-22 (Y)

CO

CONNECTOR: C-22