Mitsubishi Galant (2004+). Manual - part 1563

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-145

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 Cope with Intermittent 
Malfunction 

P.00-6

).

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-146

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-airbags should be deployed, it sends a fire sig-
nal to the SRS-ECU to deploy the side-airbags. In 
addition, the CPU diagnoses the internal compo-
nents 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 air bag module (RH) 

(squib)

• 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

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-147

DIAGNOSIS

Required Special Tools:

• 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)

• MB991223 (MB991222): Harness set (Probe)

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 

P.54C-14

).

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-148

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 Cope with Intermittent 
Malfunction 

P.00-6

).

STEP 3. Check the side impact sensor (RH) power supply 
circuit. Measure the voltage at the side impact sensor (RH) 
connector D-35.
(1) Disconnect the negative battery terminal.

(2) Disconnect side impact sensor (RH) connector D-35, and 

measure at the wiring harness side.

(3) Connect the negative battery terminal.
(4) Turn the ignition switch to the "ON" position.

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 D-35 harness side connector 

terminal 2 and ground.

Voltage should measure 9 volts or more

Q: Is the measured voltage within the specified range?

YES : Replace the side impact sensor (RH). (Refer to 

P.52B-377

). Then go to Step 5.

NO :  Go to Step 4.

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

AC308163

CONNECTOR: D-35

AC

FRONT SEAT BELT

2

1

HARNESS SIDE
CONNECTOR
(REAR VIEW)

AC201627

1 2

D-35 HARNESS SIDE
CONNECTOR
(REAR VIEW)

AQ