Mitsubishi Galant (2004+). Manual - part 1537

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-41

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 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 Cope with Intermittent 
Malfunction 

P.00-6

).

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 B1519 set?

YES : Go to Step 4.
NO :  Go to Step 5.

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-42

STEP 4. Check SRS-ECU connector C-121.

Q: Is the connector correctly engaged?

YES : Go to Step 5.
NO :  Engage the connector correctly. Then go to Step 10.

STEP 5. Check SRS-ECU connector C-121, clock spring 
connector C-307 and driver’s air bag module connector 
C-305. (Using scan tool MB991958, read the diagnostic 
trouble code.)
(1) Disconnect the negative battery terminal.

(2) Disconnect connectors C-121, C-307 and C-305, and then 

reconnect them.

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

diagnostic trouble code.

Q: Is DTC B1400 <1st squib> or B1480 <2nd squib> set?

YES : Go to Step 6.
NO :  The procedure is complete. It is assumed that DTC 

B1400 <1st squib> or B1480 <2nd squib> set 
because connector C-121, C-307 or C-305 was 
engaged improperly.

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

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

AC305235AO

C-307 (Y)

CONNECTORS: C-305, C-307

CLOCK
SPRING

11

12

13

14

C-307 HARNESS
SIDE CONNECTOR

C-305 (Y)

C-305 HARNESS
SIDE CONNECTOR

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-43

STEP 6. 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 clock spring side of 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 of 

driver’s air bag module connector C-305 (terminal No.1 and 
2 <1st squib> or 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 B1400 <1st squib> or B1480 <2nd squib> set?

YES : Go to Step 7.
NO :  Replace the driver's air bag module. (Refer to 

P.52B-368

). Then go to Step 10. 

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-44

STEP 7. 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.36 and 37 <1st squib> or 
No.34 and 35 <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 B1400 <1st squib> or B1480 <2nd squib> set?

YES : Go to Step 8.
NO :  Replace the clock spring. (Refer to 

P.52B-368

). Then 

go to Step 10. 

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)