Mitsubishi Grandis. Manual — part 992

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-20

STEP 5. Connector check: SRS-ECU connector
C-119, clock spring connector C-309 and driver’s
air bag module connector C-303 (MUT-III
diagnosis code.)
(1) Disconnect the negative battery terminal.

(2) Disconnect connectors C-119, C-309 and C-303,

and then reconnect them.

(3) Connect the negative battery terminal.
(4) Erase the diagnosis code memory, and check the

diagnosis code.

Q: Is diagnosis code B1400 <1st squib> or B1480

<2nd squib> set?

YES :

Go to Step 6.

NO :

The procedure is complete. It is assumed
that diagnosis code B1400 <1st squib> or
B1480 <2nd squib> set because connector
C-119, C-309 or C-303 was engaged
improperly.

STEP 6. Check the driver's air bag module.
(MUT-III diagnosis code.)
(1) Disconnect the negative battery terminal.

(2) Slide the outer housing of the clock spring side of

driver’s air bag module connector C-303 in the
arrow direction shown, and disconnect the
connector.

(3) Connect special tool dummy resistor (MB991865)

to special tool resistor harness (MB991866).

CAUTION

Do not insert a test probe into the terminal from
its front side directly as the connector contact
pressure may be weakened.
(4) Insert special tool MB991866 into clock spring

side of driver’s air bag module connector C-303
(terminal No.1 and 2 <1st squib> or No.3 and 4
<2nd squib>) by backprobing.

(5) Connect the negative battery terminal.

CAUTION

Always diagnosis code B1481 is set when
checking diagnosis code B1400. This is because
the second side terminal is isolated when
checking it, diagnosis code B1481 is set but this
is not a fault. In addition, always diagnosis code
B1401 is set when checking diagnosis code
B1480 because the first side terminal is isolated.
(6) Erase the diagnosis code memory, and check the

diagnosis code.

Q: Is the checked diagnosis code set?

AC311438 AD

C-119 (Y)

Connector: C-119

Harness side
(front view)

AC310153AG

Connectors: C-303, C-309 <LHD>

Clock
spring

C-303 (Y)

C-309 (Y)

Harness side
(rear view)

C-309

C-303

AC310183

AG

Connectors: C-303, C-309 <RHD>

Clock
spring

C-303 (Y)

C-309 (Y)

Harness side
(rear view)

C-309

C-303

AC306561AH

Outer housing of the
driver's air bag module connector C-303

AC306758AD

C-303 Air bag
module
connector

MB991865
(Dummy resistor : 3

ΩΩ

MB991866
(Resistor harness)

(rear view

Ω

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-21

YES :

Go to Step 7.

NO :

Replace the driver's air bag module. (Refer
to

P.52B-225

). Then go to Step 10.

STEP 7. Check the clock spring. (MUT-III
diagnosis code.)
(1) Disconnect the negative battery terminal.

(2) Disconnect the clock spring connector C-309.

(3) Connect special tool dummy resistor (MB991865)

to special tool resistor harness (MB991866).

CAUTION

Do not insert a test probe into the terminal from
its front side directly, as the connector contact
pressure may be weakened.
(4) Insert special tool MB991866 into clock spring

harness side connector C-309 (terminal No.3 and
4 <1st squib> or No.1 and 2 <2nd squib>) by
backprobing.

(5) Connect the negative battery terminal.

CAUTION

Always diagnosis code B1481 is set when
checking diagnosis code B1400. This is because
the second side terminal is isolated when
checking it, diagnosis code B1481 is set but this
is not a fault. In addition, always diagnosis code
B1401 is set when checking diagnosis code
B1480 because the first side terminal is isolated.
(6) Erase the diagnosis code memory, and check the

diagnosis code.

Q: Is the checked diagnosis code set?

YES :

Go to Step 8.

NO :

Replace the clock spring. (Refer to

P.52B-225

). Then go to Step 10.

AC310153AH

Connectors: C-309 <LHD>

Clock
spring

C-309 (Y)

Harness side
(rear view)

AC310183

AH

Connector: C-309 <RHD>

Clock
spring

C-309 (Y)

Harness side
(rear view)

AC306767

AC306767

C-309 Clock spring
connector

AC

(rear view)

MB991865
(Dummy resistor : 3

ΩΩ

MB991866
(Resistor harness)

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-22

STEP 8. Check the driver’s air bag module
circuit. Resistance measurement at SRS-ECU
connector C-119.

(1) Disconnect SRS-ECU connector C-119.

DANGER

To prevent the air bag from deploying
unintentionally, disconnect clock spring
connector C-309 to short the squib circuit.

(2) Disconnect clock spring connector C-309.

CAUTION

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

between terminals 36, 37 <1st squib> or 33, 34
<2nd squib> and the short spring to release the

AC311438 AD

C-119 (Y)

Connector: C-119

Harness side
(front view)

AC310153AH

Connectors: C-309 <LHD>

Clock
spring

C-309 (Y)

Harness side
(rear view)

AC310183

AH

Connector: C-309 <RHD>

Clock
spring

C-309 (Y)

Harness side
(rear view)

AC308144

Section
A - A

C-119 Harness side
connector
(front view)

Cable tie

Short spring

4 mm or more

Terminal

A

AD

A

<1st squib>

AC308141

Section
A - A

C-119 Harness side
connector
(front view)

Cable tie

Short spring

4 mm or more

Terminal

AD

<2nd squib>

A

A

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-23

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.
(4) Check for continuity between C-119 harness side

connector terminals 36 and 37 <1st squib> or 33
and 34 <2nd squib>.

OK: Open circuit

Q: Is the check result normal?

YES :

Erase the diagnosis code memory, and

check the diagnosis code. If diagnosis code
B1400 <1st squib> or B1481 <2nd squib>
set, replace the SRS-ECU. (Refer to

P.52B-223

). Then go to Step 10.

NO :

Go to Step 9.

STEP 9. Check the harness for short circuit
between SRS-ECU connector C-119 (terminal
No.36 and 37 <1st squib> or No.33 and 34 <2nd
squib>) and clock spring connector C-309
(terminal No.3 and 4 <1st squib> or No.1 and 2
<2nd squib>).

Q: Are harness wires between SRS-ECU connector

C-119 (terminal No.36 and 37 <1st squib> or No.33
and 34 <2nd squib>) and clock spring connector
C-309 (terminal No.3 and 4 <1st squib> or No.1 and
2 <2nd squib>) in good condition?

YES :

Go to Step 10.

NO :

Replace the harness wires between
SRS-ECU connector C-119 and clock spring
connector C-309. Then go to Step 10.

STEP 10. Check whether the diagnosis code is
reset.

Q: Is diagnosis code B1400 <1st squib> or B1480

<2nd squib> set?

AC301581

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-119 Harness side
connector (rear view)

<1st squib>

AE

AC308145

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-119 Harness side
connector (rear view)

<2nd squib>

AD

AC311438 AD

C-119 (Y)

Connector: C-119

Harness side
(front view)

AC310153AH

Connectors: C-309 <LHD>

Clock
spring

C-309 (Y)

Harness side
(rear view)

AC310183

AH

Connector: C-309 <RHD>

Clock
spring

C-309 (Y)

Harness side
(rear view)