Mitsubishi 380. Manual — part 810

SRS AIR BAG DIAGNOSIS

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-164

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-165

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 B1462 set?

YES : Go to Step 4.
NO : Replace the passenger'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-166

STEP 4. Check the driver's seat belt pre-tensioner circuit.
Measure the voltage 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.

(3) 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.
(4) Measure the voltage between D-26 harness side connector

terminals 59, 60 and body ground.
Voltage should measure 0 volt.

Q: Is the measured voltage within the specified range?

YES : Erase the diagnostic trouble code memory, and check

the diagnostic trouble code. If DTC B1462 sets,
replace the SRS-ECU (Refer to

P.52B-234

). Then go

to Step 6.

NO : Go to Step 5.

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

24DB082A

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)

SRS AIR BAG DIAGNOSIS

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-167

STEP 5. Check the harness wires for short circuit to power
supply between SRS-ECU connector D-26 (terminal No.59
and 60) and driver's seat belt pre-tensioner connector D-33
(terminal No.1 and 2).
Q: Are the harness wires between SRS-ECU connector

D-26 (terminal No.59 and 60) and driver's seat belt
pre-tensioner connector D-33 (terminal No.1 and 2) in
good condition?
YES : Go to Step 6.
NO : Replace the harness wires between SRS-ECU

connector D-26 and driver's seat belt pre-tensioner
connector D-33. Then go to Step 6.

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 B1462 set?

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

AC307915AC

CONNECTOR: D-33

D-33 (B)

FORWARD

CENTER
PILLAR

HARNESS SIDE
CONNECTOR
(FRONT VIEW)

2 1

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)

00DB076A

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827