Mitsubishi Galant (2004+). Manual - part 1552

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-101

STEP 3. Check the passenger's air bag module. (Using 
scan tool MB991958, read the diagnostic trouble code.)

(1) Disconnect the negative battery terminal.
(2) Disconnect the passenger’s air bag module connector 

C-110.

(3) Slide the outer housing of the clock spring side of 

passenger’s air bag module connector C-110 in the arrow 
direction shown, and disconnect the connector.

(4) 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.
(5) Insert special tool MB991866 into the harness side 

connector C-110 (terminal No.1 and 2 <1st squib> or 
terminal No.3 and 4 <2nd squib>) by backprobing.

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

diagnostic trouble code.

Q:  Is DTC B1412 <1st squib> B1492 <2nd squib> set?

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

P.52B-368

). Then go to Step 6. 

AC307137AC

C-110 (Y)

FRONT DECK
CROSSMEMBER

CONNECTOR: C-110

HARNESS SIDE 
CONNECTOR
(REAR VIEW)

AC306561AD

OUTER HOUSING OF THE PASSENGER'S 
AIR BAG MODULE CONNECTOR C-110

AC306760AB

MB991865 (DUMMY 
RESISTOR: 3 

Ω)

MB991866
(RESISTOR HARNESS)

C-110 HARNESS 
CONNECTOR

C-110
PASSENGER'S
AIR BAG MODULE 
CONNECTOR

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-102

STEP 4. Check the passenger’s air bag module circuit. 
Measure the voltage 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 passenger’s air bag module connec-
tor C-110 to short the squib circuit.

(2) Disconnect the passenger's air bag module connector 

C-110.

(3) Slide the outer housing of the clock spring side of 

passenger’s air bag module connector C-110 in the arrow 
direction shown, and disconnect the connector.

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

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

AC307137AC

C-110 (Y)

FRONT DECK
CROSSMEMBER

CONNECTOR: C-110

HARNESS SIDE 
CONNECTOR
(REAR VIEW)

AC306561AD

OUTER HOUSING OF THE PASSENGER'S 
AIR BAG MODULE CONNECTOR C-110

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-103

CAUTION

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

connector terminals 27 and 28 <1st squib> or 30 and 31 

<2nd squib> 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 B1412 <1st 
squib> B1492 <2nd squib> sets, replace the 
SRS-ECU. (Refer to 

P.52B-365

). Then go to Step 6.

NO :  Go to Step 5. 

STEP 5. Check the harness wires for short circuit to power 
supply between SRS-ECU connector C-121 (terminal No.27 

and 28 <1st squib> or terminal No.30 and 31 <2nd squib>) 
and passenger's air bag module connector C-110 (terminal 
No.1 and 2 <1st squib> terminal No.4 and 3 <2nd squib>). 

AC301588

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

AC308153

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

AC307137AC

C-110 (Y)

FRONT DECK
CROSSMEMBER

CONNECTOR: C-110

HARNESS SIDE 
CONNECTOR
(REAR VIEW)

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

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-104

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.27 and 28 <1st squib> or terminal 
No.30 and 31 <2nd squib>) and passenger's air bag 
module connector C-110 (terminal No.1 and 2 <1st 
squib> terminal No.4 and 3 <2nd squib>) in good 
condition?
YES : Go to Step 6.
NO :  Replace the harness wires between SRS-ECU 

connector C-121 and passenger's air bag module 
connector C-110. 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 B1412 <1st squib> B1492 <2nd squib> set?

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

AC305233

C-22 (Y)

CO

CONNECTOR: C-22

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827