Mitsubishi Galant 9G. Manual - part 1433

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-142

STEP 5. Check the harness wires for short circuit to 
ground between SRS-ECU connector C-120 (terminal 
No.57 and 58) and side-airbag module (RH) connector D-32 
(terminal No.1 and 2).
Q: Are the harness wires between SRS-ECU connector 

C-120 (terminal No.57 and 58) and side-airbag module 
(RH) connector D-32 (terminal No.1 and 2) in good 
condition?
YES : Go to Step 6.
NO :  Replace the harness wires between SRS-ECU 

connector C-120 and side-airbag module (RH) 
connector D-32. 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 B1423 set?

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

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

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-143

DTC B1426: Side Impact Sensor (RH) System for Fault 1
DTC B1436: Side Impact Sensor (LH) System for Fault 1

CAUTION

If DTC B1426 or B1436 is set in the SRS-ECU, 
always diagnose the CAN main bus line.

.

DTC SET CONDITIONS

These DTCs are set if the following conditions are 
detected from the analog G-sensor inside the side 
impact sensor output:

• Analog G-sensor is not operating.

• Analog G-sensor characteristics are abnormal.

• Analog G-sensor output is abnormal.

.

TROUBLESHOOTING HINTS

Malfunction of side impact sensor (RH) (for DTC 
B1426) and side impact sensor (LH) (for DTC 
B1436)

.

DIAGNOSIS

Required Special Tool:

• MB991958: Scan Tool (MUT-III Sub Assembly)

• MB991824: Vehicle Communication Interface (V.C.I.)

• MB991827: MUT-III USB Cable

• MB991910: MUT-III Main Harness A (Vehicles with CAN 

communication system)

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 ).

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-144

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 ).

STEP 3. Check the side impact sensor. (Using scan tool 
MB991958, read the diagnostic trouble code.)
Replace side impact sensor (RH) (for DTC B1426) and side 
impact sensor (LH) (for DTC B1436) (Refer to 

P.52B-377

).

Check the diagnostic trouble code.

Q: Is either DTC B1426 or B1436 set?

YES : Replace the SRS-ECU (Refer to 

P.52B-365

).

NO :  The procedure is complete.

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-145

DTC B1427: Side Impact Sensor (RH) Power Supply Circuit System

CAUTION

If DTC B1427 is set in the SRS-ECU, always diag-
nose the CAN main bus line.

.

CIRCUIT OPERATION

The side impact sensor includes an analog G sensor 
and CPU, etc. The CPU monitors the analog G sen-
sor output signal. If the CPU judges that the side-air-
bags should be deployed, it sends a fire signal to the 
SRS-ECU to deploy the side-airbags. In addition, the 
CPU diagnoses the internal components of the side 
impact sensor. If a malfunction occurs, it requests the 
SRS-ECU to set a diagnostic trouble code.

.

DTC SET CONDITIONS

This DTC will set when the power supply voltage to 
the side impact sensor (RH) remains less than a pre-
determined value for five seconds. However, if the 
system returns to normal condition, code number 
B1427 will be erased automatically and the SRS 
warning light will go out.

.

TROUBLESHOOTING HINTS

• Damaged wiring harness or connectors

• Malfunction of the side impact sensor (RH)

• Malfunction of the SRS-ECU

.

SIDE IMPACT 
SENSOR (RH)

INTERFACE 
CIRCUIT

SRS-ECU

Side Impact Sensor (RH) Circuit

AC305362

CONNECTOR: C-120

C-120 (Y)

AC

SRS-ECU

AC308163

CONNECTOR: D-35

AB

FRONT SEAT BELT