Mitsubishi Galant (2004+). Manual - part 1574

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-189

STEP 7. Check the passenger's seat belt pre-tensioner 
circuit. Measure the resistance at the SRS-ECU connector 
C-120.

(1) Disconnect SRS-ECU connector C-120.

DANGER

To prevent the seat belt pre-tensioner from deploying 
unintentionally, disconnect the passenger’s seat belt 
pre-tensioner connector D-33 to short the squib cir-
cuit.

(2) Disconnect passenger's seat belt pre-tensioner connector 

D-33. Use a flat-tipped screwdriver to unlock the locking 
button at the harness side connector by withdrawing it 
toward you in two stages, and then disconnect the 
connector.

CAUTION

Insert an insulator such as a cable tie to a depth of 4mm 
(0.16 inch) or more, otherwise the short spring will not be 
released.
(3) Insert a cable tie [3 mm (0.12 inch) wide, 0.5 mm (0.02 inch) 

thick] between terminals 59, 60 and the short spring to 
release the short spring.

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)

AC307915 AC

CONNECTOR: D-33

D-33 (B)

FORWARD

CENTER 
PILLAR

HARNESS SIDE
CONNECTOR
(FRONT VIEW)

2 1

AC103556AU

LOCKING BUTTON

FLAT-TIP SCREW
DRIVER

D-33 HARNESS 
SIDE CONNECTOR

D-33 PASSENGER'S 
SEAT BELT
PRE-TENSIONER
CONNECTOR

AC301608

SEC-
TION
A - A

C-120 HARNESS SIDE 
CONNECTOR (FRONT VIEW)

CABLE TIE

SHORT SPRING

4 mm OR MORE

TERMINAL

A

AE

A

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-190

CAUTION

Do not insert a test probe into the terminal from its front 
side directly as the connector contact pressure may be 
weakened.
(4) Check for continuity between C-120 harness side connector 

terminals 59 and 60.

It should be open circuit.

Q: Does continuity exist?

YES : Erase the diagnostic trouble code memory, and check 

diagnostic trouble code. If DTC B1460 set, replace 
the SRS-ECU (Refer to 

P.52B-365

). Then go to Step 

9.

NO :  Go to Step 8.

STEP 8. Check the harness for short circuit between 
SRS-ECU connector C-120 (terminal No.59 and 60) and 
passenger’s seat belt pre-tensioner connector D-33 
(terminal No.1 and 2).

Q: Are harness wires between SRS-ECU connector C-120 

(terminal No.59 and 60) connector and passenger’s seat 
belt pre-tensioner connector (terminal No.1 and 2) in 
good condition?
YES : Go to Step 9.
NO :  Replace the harness wires between SRS-ECU 

connector C-120 and passenger’s seat belt 
pre-tensioner connector D-33. Then go to Step 9.

AC301572

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)

AE

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)

AC307915 AC

CONNECTOR: D-33

D-33 (B)

FORWARD

CENTER 
PILLAR

HARNESS SIDE
CONNECTOR
(FRONT VIEW)

2 1

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-191

STEP 9. 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 B1460 set?

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

DTC B1461: Seat Belt Pre-Tensioner (RH) (Squib) System Fault 2 (Open in the Squib Circuit)

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

SEAT BELT
PRETENSIONER
(RH)

AIR BAG DRIVE CIRCUIT

SRS-ECU

CONNECTOR
LOCK SWITCH

CONNECTOR
LOCK SWITCH

: CONNECTOR CONNECTED: ON

  CONNECTOR DISCONNECTED: OFF

Passenger's (Front) Seat Belt Pre-Tensioner (Squib) Circuit

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-192

CAUTION

If DTC B1461 is set in the SRS-ECU, always diag-
nose 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 pre-tensioner will deploy. 

.

DTC SET CONDITIONS
This DTC is set if there is abnormal resistance 
between the input terminals of the passenger's seat 
belt pre-tensioner (squib).

.

TROUBLESHOOTING HITS

• Open circuit in the passenger's seat belt 

pre-tensioner (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

• MB991865: Dummy resistor

• MB991884: Resister harness (For Pre-tensioner)

AC305362

CONNECTOR: C-120

C-120 (Y)

AC

SRS-ECU

AC307915 AB

CONNECTOR: D-33

D-33 (B)

FORWARD

CENTER 
PILLAR