Mitsubishi Galant 9G. Manual - part 1428

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-122

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 "ON" position.
(3) Diagnose the CAN bus line.
(4) Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is the check result satisfactory?

YES : Go to Step 2
NO :  Repair the CAN bus lines (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 "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

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SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-123

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.

STEP 4. Check SRS-ECU connector C-120.
Q: Is the connector correctly engaged?

YES : Go to Step 5.
NO :  Engage the connector correctly. Then go to Step 9.

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

AC305362

CONNECTOR: C-120

C-120 (Y)

AG

SRS-ECU

63

55

51

69

61

66

58

65

64

56 57

68

60

67

59

70

62

53

52 B

A

54

C-120 
Harness side
connector 
(rear view)

SRS AIR BAG DIAGNOSIS

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SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-124

STEP 5. Check SRS-ECU connector C-120 and side-airbag 
module (RH) connector D-32. (Using scan tool MB991958, 
read the diagnostic trouble code.)
(1) Disconnect the negative battery terminal.
(2) Disconnect connectors C-120 and D-32, 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 B1420 out put?

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

B1420 set because connector C-120 or D-32 was 
engaged improperly.

AC305362

CONNECTOR: C-120

C-120 (Y)

AG

SRS-ECU

63

55

51

69

61

66

58

65

64

56 57

68

60

67

59

70

62

53

52 B

A

54

C-120 
Harness side
connector 
(rear view)

AC307779

D-32 (R)

AD

2

1

HARNESS SIDE
CONNECTOR
(REAR VIEW)

CONNECTOR : D-32

SRS AIR BAG DIAGNOSIS

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SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-125

STEP 6. Check the side-airbag module (RH). (Using scan 
tool MB991958, read the diagnostic trouble code.)
(1) Disconnect the negative battery terminal.
(2) Disconnect the side-airbag module (RH) connector D-32.

(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 the D-32 harness side 

connector by backprobing.

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

diagnostic trouble code. 

Q: Is DTC B1420 set?

YES : Go to Step 7.
NO :  Replace the seatback frame of the front seat (RH) 

(Refer to GROUP 52A, Front Seat 

P.52A-25

). Then 

go to Step 9.

AC307779

D-32 (R)

AD

2

1

HARNESS SIDE
CONNECTOR
(REAR VIEW)

CONNECTOR : D-32

AC006042BO

MB991866
(RESISTOR HARNESS)

D-32 HARNESS SIDE
CONNECTOR

D-32 SIDE-AIRBAG 
MODULE (RH) CONNECTOR

MB991865 (DUMMY 
RESISTOR: 3

 

Ω

)