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