Mitsubishi 380. Manual — part 811

SRS AIR BAG DIAGNOSIS

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-168

DTC B1463: Seat Belt Pre-Tensioner (RH) (Squib) System Fault for Ground Circuit (Short-Circuit to
Ground)

CAUTION

If DTC B1463 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 driver's seat belt
pre-tensioner (squib).

.

TROUBLESHOOTING HITS

• Damaged wiring harnesses or connectors

• Short to the ground in the driver's seat belt

pre-tensioner (squib) harness

• Malfunction of the SRS-ECU

• Refer to circuit diagrams GROUP-

90

• Refer to configuration diagrams GROUP-

80

.

24DB063A

CONNECTOR: D-26

SRS-ECU

63

55

51

69

61

66

58

65

64

5657

68

60

67

59

70

62

53

52 B A

54

D-26 (Y)

D-26 FLOOR

HARNESS

CONNECTOR

(REAR VIEW)

AC307915AB

CONNECTOR: D-33

D-33 (B)

FORWARD

CENTER
PILLAR

SRS AIR BAG DIAGNOSIS

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-169

DIAGNOSIS

Required Special Tools:

• MB991958: diagnostic 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: Resistor harness (For Pre-tensioner)

STEP 1. Using diagnostic tool MB991958, diagnose the
CAN bus line.

CAUTION

To prevent damage to diagnostic tool MB991958, always
turn the ignition switch to the "LOCK" (OFF) position
before connecting or disconnecting diagnostic tool
MB991958.
(1) Connect diagnostic tool MB991958. Refer to "How to

connect the diagnostic tool

P.52B-19

."

(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 ).

00DB076A

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

SRS AIR BAG DIAGNOSIS

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-170

STEP 2. Recheck for diagnostic trouble code.
Check again if the DTC is set.
(1) Erase the DTC.
(2) Turn the ignition switch to "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 driver's seat belt pre-tensioner. (Using
diagnostic tool MB991958, read the diagnostic trouble
code.)
(1) Disconnect the negative battery terminal.
(2) Disconnect driver'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.

(3) Connect special tool MB991865 to special tool MB991884.
(4) Connect special tool MB991884 to the D-33 harness side

connector.

(5) Connect the negative battery terminal.
(6) Erase diagnostic trouble code memory, and then check the

diagnostic trouble code.

Q: Is DTC B1463 set?

YES : Go to Step 4.
NO : Replace the driver's seat belt pre-tensioner (Refer to

P.52B-250

). Then go to Step 6.

00DB076A

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

AC307915AC

CONNECTOR: D-33

D-33 (B)

FORWARD

CENTER
PILLAR

HARNESS SIDE
CONNECTOR
(FRONT VIEW)

2 1

MB991884

MB991885

AC103283AP

MB991865
(DUMMY RESISTOR : 3Ω)

MB991884
(RESISTOR
HARNESS)

D-33 HARNESS SIDE
CONNECTOR

SRS AIR BAG DIAGNOSIS

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-171

STEP 4. Check the driver's seat belt pre-tensioner circuit.
Measure the resistance at the SRS-ECU connector D-26.
(1) Disconnect SRS-ECU connector D-26.

(2) Disconnect driver'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

Do not insert a test probe into the terminal from its front
side directly, as the connector contact pressure may be
weakened.
(3) Check for continuity between D-26 harness side connector

terminals 59, 60 and body ground.
It should be open circuit.

Q: Does continuity exist?

YES : Go to Step 5.
NO : Erase the diagnostic trouble code memory, and check

the diagnostic trouble code. If DTC B1463 sets,
replace the SRS-ECU (Refer to

P.52B-234

). Then go

to Step 6.

24DB063A

CONNECTOR: D-26

SRS-ECU

63

55

51

69

61

66

58

65

64

5657

68

60

67

59

70

62

53

52 B A

54

D-26 (Y)

D-26 FLOOR

HARNESS

CONNECTOR

(REAR VIEW)

AC307915AC

CONNECTOR: D-33

D-33 (B)

FORWARD

CENTER
PILLAR

HARNESS SIDE
CONNECTOR
(FRONT VIEW)

2 1

24DB083A

63

55

51

69

61

66

58

65

64

5657

68

60

67

59

70

62

53

52 B A

54

D-26 FLOOR HARNESS

SIDE CONNECTOR

(REAR VIEW)