Mitsubishi Grandis. Manual — part 1007

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-80

STEP 2. Check whether the diagnosis code is
reset.

Check again if the diagnosis code is set.
(1) Erase the diagnosis code.
(2) Ignition: LOCK (OFF) position to ON
(3) On completion, check that the diagnosis code is

not reset.

Q: Is the diagnosis code 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 Cope with
Intermittent Malfunction

P.00-5

).

STEP 3. MUT-III diagnosis code

CAUTION

To prevent damage to MUT-III MB991958, always
turn the ignition switch to the "LOCK" (OFF)
position before connecting or disconnecting
MUT-III MB991958.
(1) Turn the ignition switch to the "ON" position.
(2) Check if the diagnosis code is set.
(3) Turn the ignition switch to the "LOOK (OFF)"

position.

Q: Is diagnosis code B1519 set?

YES :

Go to Step 4.

NO :

Go to Step 5.

STEP 4. Connector lock check: SRS-ECU
connector C-140 (MUT-III diagnosis code).
(1) Disconnect the negative battery terminal.

(2) Disconnect connectors C-120 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 B1430 out put?

YES :

Go to Step 5.

NO :

The procedure is complete. It is assumed
that diagnosis code B1430 set as connector
C-120 was engaged improperly.

STEP 5. Connector lock check: SRS-ECU
connector C-120 and side-airbag module (LH)
connector D-22 (MUT-III diagnosis code)
(1) Disconnect the negative battery terminal.

(2) Disconnect connectors C-120 and D-22 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 B1430 out put?

YES :

Go to Step 6.

NO :

The procedure is complete. It is assumed
that diagnosis code B1430 set because
connector C-120 or D-22 was engaged
improperly.

STEP 6. Check the side-airbag module (LH).
(MUT-III diagnosis code.)
(1) Disconnect the negative battery terminal.

(2) Disconnect the side-airbag module (LH)

AC311438 AE

C-120 (Y)

Connector: C-120

Harness side
(front view)

AC311438 AE

C-120 (Y)

Connector: C-120

Harness side
(front view)

AC303521

AD

D-22 (R)

Connector: D-22

Harness side
(front view)

AC303521

AD

D-22 (R)

Connector: D-22

Harness side
(front view)

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-81

connector D-22.

(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 the D-22

harness side connector by backprobing.

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

diagnosis code.

Q: Is diagnosis code B1430 set?

YES :

Go to Step 7.

NO :

Replace the seatback frame of the front
seat (LH). (Refer to GROUP 52A, Front
Seat

P.52A-24

).

STEP 7. Check the side-airbag module (LH)
circuit. Resistance measurement at the SRS-ECU
connector C-120.

(1) Disconnect SRS-ECU connector C-120.

DANGER

To prevent the air bag from deploying
unintentionally, disconnect the side-airbag
module (LH) connector D-22 to short the
squib circuit.

(2) Disconnect left hand side-airbag module (LH)

connector D-22.

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.
(3) Insert a cable tie [3 mm wide, 0.5 mm thick]

between terminals 9, 10 and the short spring to

AC006042 BY

MB991866
(Resistor harness)

D-22 Harness side
connector

D-22 Side-airbag
module (LH) connector

MB991865 (Dummy
resistor: 3

Ω)

AC311438 AE

C-120 (Y)

Connector: C-120

Harness side
(front view)

AC303521

AD

D-22 (R)

Connector: D-22

Harness side
(front view)

AC308180 AD

A

A

C-120 Harness side
connector (front view)

Terminal

Cable tie

Short spring

4 mm or more

Sec-
tion
A - A

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-82

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.
(4) Check for continuity between C-120 harness side

connector terminals 9 and 10.

OK: Open circuit

Q: Is the check result normal?

YES :

Go to Step 8.

NO :

Repair the harness wires between
SRS-ECU connector C-120 (terminal No.9
and 10) and side-airbag module (LH)
connector D-22 (terminal No.1 and 2).

STEP 8. Check whether the diagnosis code is
reset.

Q: Is diagnosis code B1430 set?

YES :

Replace the SRS-ECU (Refer to

P.52B-223

).

NO :

An intermittent malfunction is suspected
(Refer to GROUP 00, How to Use
Troubleshooting/Inspection Service Points

P.00-5

).

Code No.B1431: Side-Airbag Module (LH) (Squib) System Fault 2 (Open in the Squib Circuit)

AC308174

A

B

18

10

15

7

13

5

14

6

16

8

17

9

19

11

20

12

1 2

3 4

C-120 Harness side
connector (rear view)

AE

Wire colour code
B : Black LG : Light green G : Green L : Blue W : White Y : Yellow SB : Sky blue
BR : Brown O : Orange GR : Gray R : Red P : Pink V : Violet

SIDE AIR BAG
MODULE
(SQUIB) (LH)

SRS-ECU

CONNECTOR
LOCK SWITCH

CONNECTOR
LOCK SWITCH

: CONNECTOR
CONNECTED: ON
CONNECTOR
DISCONNECTED: OFF

NOTE

Side-Airbag Module (LH) (Squib) Circuit

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-83

CAUTION

If diagnosis code B1431 is set in the combination
meter, always diagnose the CAN bus lines.

OPERATION

• The SRS-ECU judges how severe a collision is

by detecting signals from the left and right side
impact sensors. If the impact is over a
predetermined level, the SRS-ECU sends an
ignition signal. At this time, if the side-airbag
safing G-sensor is on, the SRS side-airbag will
inflate.

• The ignition signal is input to the side-airbag

module to inflate the side-airbag.

DIAGNOSIS CODE SET CONDITIONS

This diagnosis code is set if there is abnormal
resistance between the input terminals of the
side-airbag module (LH) (squib).

PROBABLE CAUSES

• Open circuit in the side-airbag module (squib)

(LH) circuit

• Improper connector contact

• Malfunction of the SRS-ECU

DIAGNOSIS PROCEDURE

STEP 1. MUT-III CAN bus diagnostics

Use the MUT-III to diagnose the CAN bus lines.

Q: Is the check result normal?

YES :

Go to Step 2

NO :

Repair the CAN bus lines (Refer to GROUP
54D, Diagnosis-Can Bus Diagnostic Chart

P.54D-16

).

STEP 2. Check whether the diagnosis code is
reset.

Check again if the diagnosis code is set.
(1) Erase the diagnosis code.
(2) Ignition: LOCK (OFF) position to ON
(3) On completion, check that the diagnosis code is

not reset.

Q: Is the diagnosis code 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 Cope with
Intermittent Malfunction

P.00-5

).

STEP 3. Check the side-airbag module (LH).
(MUT-III diagnosis code.)
(1) Disconnect the negative battery terminal.

(2) Disconnect the side-airbag module (LH)

connector D-22.

(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 the D-22

harness side connector by backprobing.

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

the diagnosis code.

Q: Is diagnosis code B1431 set?

YES :

Go to Step 4.

NO :

Replace the seatback frame of the front
seat (LH). (Refer to GROUP 52A, Front
Seat

P.52A-24

).

AC303521

AD

D-22 (R)

Connector: D-22

Harness side
(front view)

AC006042 BY

MB991866
(Resistor harness)

D-22 Harness side
connector

D-22 Side-airbag
module (LH) connector

MB991865 (Dummy
resistor: 3

Ω)