Mitsubishi Galant 9G. Manual — part 1425

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-110

STEP 5. Check the harness wires for short circuit to
ground 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> or terminal No.4 and 3
<2nd squib>).

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> or 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.

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

AC305233

C-22 (Y)

CO

CONNECTOR: C-22

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-111

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 B1413 <1st squib> B1493 <2nd squib> set?

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

DTC B1417: Front Impact Sensor (LH) Power Supply Circuit System

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

Front Impact Sensor Circuit

INTERFACE CIRCUIT

SRS-ECU

FRONT IMPACT
SENSOR (LH)

FRONT IMPACT
SENSOR (RH)

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-112

CAUTION

If DTC B1417 is set in the SRS-ECU, always diag-
nose the CAN main bus line.

.

CIRCUIT OPERATION

The front 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 front air
bags should be deployed, it sends a fire signal to the
SRS-ECU to deploy the front air bags. In addition,
the CPU diagnoses the internal components of the
front 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 front impact sensor (LH) remains less than a pre-
determined value for five seconds. However, if the
system returns to normal condition, code number
B1417 will be erased automatically and the SRS
warning light will go out.

.

TROUBLESHOOTING HINTS

• Damaged wiring harness or connectors

• Malfunction of the front impact sensor (LH)

• Malfunction of the SRS-ECU

.

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)

AC305210

CONNECTOR: A-23

AW

A-23 (Y)

AC305233 AO

CONNECTOR: C-22

C-22 (Y)

AC305231BF

CONNECTOR: C-29

AC305362

CONNECTOR: C-121

C-121 (Y)

AD

SRS-ECU

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-113

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