Mitsubishi 380. Manual — part 785

SRS AIR BAG DIAGNOSIS

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-64

STEP 7. Check the passenger’s air bag module circuit at
SRS-ECU connector C-121.
(1) Disconnect SRS-ECU connector C-121.

DANGER

To prevent the air bag from deploying unintentionally,
disconnect the passenger’s air bag module connec-
tor C-110 to short the squib circuit.

(2) Disconnect the passenger's air bag module connector

C-110.

(3) Slide the outer housing of the clock spring side of driver’s

air bag module connector C-110 in the arrow direction
shown, and disconnect the connector.

24DB062A

CONNECTOR: C-121

C-121 (Y)

SRS-ECU

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

C-121

INSTRUMENT

HARNESS

CONNECTOR

(REAR VIEW)

52DB018A

C-110 (Y)

FRONT DECK
CROSSMEMBER

CONNECTOR: C-110

HARNESS SIDE
CONNECTOR
(REAR VIEW)

AC306561AD

OUTER HOUSING OF THE PASSENGER'S
AIR BAG MODULE CONNECTOR C-110

SRS AIR BAG DIAGNOSIS

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-65

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.
(4) Insert a cable tie [3 mm (0.12 inch) wide, 0.5 mm (0.02 inch)

thick] between terminals 37 and 36 , and the short spring to
release the short spring.

CAUTION

Do not insert a test probe into the terminal from its front
side directly as the connector contact pressure may be
weakened.
(5) Check for continuity between C-121 harness side connector

terminals 37 and 36 .
It should be open circuit.

Q: Does continuity exist?

YES : Go to Step 8.
NO : Erase the diagnostic trouble code memory, and check

the diagnostic trouble code. If DTC B1410 set,
replace the SRS-ECU (Refer to

P.52B-234

). Then go

to Step 9.

STEP 8. Check the harness for short circuit between
SRS-ECU connector C-121 (terminal No.37 and 36 ) and
passenger's air bag module connector C-110 (terminal
No.1 and 2 ).
Q: Are harness wires between SRS-ECU connector C-121

(terminal No.37 and 36 ) and passenger's air bag module
connector C-110 (terminal No.1 and 2 ) 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.

AC308142

SECTION
A - A

C-121 HARNESS SIDE
CONNECTOR
(FRONT VIEW)

CABLE TIE

SHORT SPRING

4 mm OR MORE

TERMINAL

AB

<1ST SQUIB>

A

A

AC308143

SECTION
A - A

C-121 HARNESS SIDE
CONNECTOR
(FRONT VIEW)

CABLE TIE

SHORT SPRING

4 mm OR MORE

TERMINAL

AB

<2ND SQUIB>

A

A

52DB018A

C-110 (Y)

FRONT DECK
CROSSMEMBER

CONNECTOR: C-110

HARNESS SIDE
CONNECTOR
(REAR VIEW)

24DB062A

CONNECTOR: C-121

C-121 (Y)

SRS-ECU

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

C-121

INSTRUMENT

HARNESS

CONNECTOR

(REAR VIEW)

SRS AIR BAG DIAGNOSIS

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-66

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 set?

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

00DB076A

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

SRS AIR BAG DIAGNOSIS

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-67

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

CAUTION

If DTC B1411 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 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

• Refer to circuit diagrams GROUP-

90

• Refer to configuration diagrams GROUP-

80

.

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 (Vehicles with CAN

Communication System)

• MB991865: Dummy resister

• MB991866: Resistor harness

52DB017A

C-110 (Y)

FRONT DECK
CROSSMEMBER

CONNECTOR: C-110

24DB062A

CONNECTOR: C-121

C-121 (Y)

SRS-ECU

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

C-121

INSTRUMENT

HARNESS

CONNECTOR

(REAR VIEW)