Mitsubishi Galant 9G. Manual - part 1469

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-286

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

Q: Is the CAN bus line found to be normal?

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

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-287

STEP 3. Check the seat slide sensor. (Using scan tool 
MB991958, read the diagnostic trouble code.)
(1) Disconnect the negative battery terminal.
(2) Disconnect the seat slide sensor connector D-27.

(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-27 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 B1507 set?

YES : Go to Step 4.
NO :  Replace the seat slide sensor (Refer to 

P.52B-384

). 

Then go to Step 5.

AC308165

CONNECTOR : D-27

AC

D-27 (GR)

HARNESS SIDE

AC006042BQ

MB991866
(RESISTOR HARNESS)

D-27 HARNESS SIDE
CONNECTOR

D-27 SEAT SLIDE
SENSOR CONNECTOR

MB991865 (DUMMY 
RESISTOR: 3

 

Ω

)

(REAR VIEW)

SRS AIR BAG DIAGNOSIS

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SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-288

STEP 4. Check the seat slide sensor circuit. Measure the 
resistance at the SRS-ECU connector C-122.
(1) Disconnect SRS-ECU connector C-122.

(2) Disconnect seat slide sensor connector D-27.

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-122 harness side connector 

terminals 1, 2 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 B1507 sets, 
replace the SRS-ECU (Refer to 

P.52B-365

). Then go 

to Step 6.

NO :  Go to Step 5.

AC305362

CONNECTOR: C-122

C-122 (Y)

AE

SRS-ECU

AC308165

CONNECTOR : D-27

AC

D-27 (GR)

HARNESS SIDE

AC308188

A

B

18

10

15

7

13

5

14

6

16

8

17

9

19

11

20

12

1 2

3 4

C-122 HARNESS SIDE
CONNECTOR
(REAR VIEW)

AB

SRS AIR BAG DIAGNOSIS

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SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-289

STEP 5. Check the harness wires for short circuit to 
ground between SRS-ECU connector C-122 (terminal No.2 
and 1) and seat slide sensor connector D-27 (terminal No.1 
and 2).
Q: Are the harness wires between SRS-ECU connector 

C-122 (terminal No.2 and 1) and seat slide sensor 
connector D-27 (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 seat slide sensor connector 
D-27. 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 B1507 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

AC308165

CONNECTOR : D-27

AC

D-27 (GR)

HARNESS SIDE

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827