Mitsubishi Galant 9G. Manual - part 1420

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-90

STEP 8. Check the harness for short circuit 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> 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 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> 
terminal No.4 and 3 <2nd squib>) in good condition?
YES : Go to Step 9.
NO :  Replace the harness wires between SRS-ECU 

connector C-121 and passenger’s air bag module 
connector C-110. Then go to Step 9.

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-91

STEP 9. Check 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 B1410 <1st squib> or B1490 <2nd squib> set?

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

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-92

DTC B1411: Passenger’s (Front) Air Bag Module (1st Squib) System Fault 2 (Open in the Squib 
Circuit)
DTC B1491: Passenger’s (Front) Air Bag Module (2nd Squib) System Fault 2 (Open in the Squib 
Circuit)

Passenger's (Front) Air Bag Module (1st Squid and 2nd Squib) Circuit

AIR BAG MODULE 
(SQUIB) (PASSENGER'S SIDE)

AIR BAG DRIVE CIRCUIT

: CONNECTOR CONNECTED
 : ON
  CONNECTOR DICONNECTED
 : OFF

SRS-ECU

CONNECTOR
LOCK SWITCH

NOTE

AC305233 AO

CONNECTOR: C-22

C-22 (Y)

AC307137AD

C-110 (Y)

FRONT DECK
CROSSMEMBER

CONNECTOR: C-110

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-93

CAUTION

If DTC B1411 <1st squib> or B1491 <2nd squib> 
is set in the SRS-ECU, always diagnose the CAN 
main bus line.

.

CIRCUIT OPERATION

• The SRS-ECU judges how severe a collision is 

by detecting signals from the front impact sensors 
and the front air bag analog G-sensor. If the 
impact is over a predetermined level, the 
SRS-ECU sends an ignition signal. At this time, if 
the front air bag safing G-sensor is on, the SRS 
air bag will inflate. 

• The ignition signal is input to the air bag module 

via the clock spring to inflate the air bag.

.

DTC SET CONDITIONS

This DTC is set if there is abnormal resistance 
between the input terminals of the passenger’s air 
bag module (squib). However, if no DTC reset, the 
SRS warning light will be switched off (DTC will be 
retained). 

.

TROUBLESHOOTING HINTS

• Open circuit in the passenger's air bag module 

(squib) circuit

• Improper connector contact

• 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)

• MB991865: Dummy resister

• MB991866: Resister harness

AC305362

CONNECTOR: C-121

C-121 (Y)

AD

SRS-ECU