Mitsubishi Grandis. Manual — part 1009

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-88

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 the diagnosis code memory, and check the

diagnosis code.

Q: Is diagnosis code B1433 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

).

STEP 4. Check the side-airbag module (RH)
circuit. Voltage 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.

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)

AC311438 AE

C-120 (Y)

Connector: C-120

Harness side
(front view)

AC303521

AD

D-22 (R)

Connector: D-22

Harness side
(front view)

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-89

(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 C-120 harness

side connector terminals 9, 10 and body earth.

OK: 0 V

Q: Is the check result normal?

YES :

Go to Step 5.

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 5. Check whether the diagnosis code is
reset.

Q: Is diagnosis code B1433 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.B1437: Side Impact Sensor (LH) Power Supply Circuit System

AC308177

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)

AD

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 IMPACT
SENSOR (FRONT: LH)

SRS-ECU

Side Impact Sensor (Front) (LH) Circuit

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-90

CAUTION

If diagnosis code B1437 is set in the SRS-ECU,
always diagnose the CAN main bus line.

OPERATION

The side impact sensor includes an analogue G
sensor and CPU, etc. The CPU monitors the
analogue G sensor output signal. If the CPU judges
that the side-airbags and curtain air bags should be
deployed, it sends a fire signal to the SRS-ECU to
deploy the side-airbags and curtain air bags. In
addition, the CPU diagnoses the internal
components of the side impact sensor. If a
malfunction occurs, it requests the SRS-ECU to set a
diagnosis code.

DIAGNOSIS CODE SET CONDITIONS

This diagnosis code is set if the power supply voltage
of the side impact sensor (LH) drops below the rated
value for a continuous period of 5 seconds or more.
However, diagnosis code B1437 will be automatically
cleared and the SRS warning lamp will switch off if
the condition returns to normal.

TROUBLESHOOTING HINTS

• Damaged wiring harnesses or connectors

• Malfunction of the side impact sensor (LH)

• Malfunction of the SRS-ECU

PROBABLE CAUSES

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 line (Refer to GROUP
54D, Diagnosis

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 impact sensor (LH)
power supply circuit. Voltage measurement at the
side impact sensor (LH) connector D-18.
(1) Disconnect the negative battery terminal.

(2) Disconnect side impact sensor (LH) connector

D-18,, and measure at the wiring harness side.

(3) Connect the negative battery terminal.
(4) 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.
(5) Measure the voltage between the D-18 harness

side connector terminal 1 and body earth.

OK: 9 V or more

Q: Is the check result normal?

YES :

Replace the side impact sensor (LH) (Refer

to

P.52B-236

). Then go to Step 5.

NO :

Go to Step 4.

AC302579AC

D-18 (Y)

Connector: D-18

Centre
pillar

Front vehicle

Harness side
(front view)

AC311097

D-18 Harness side
connector
(rear view)

AI

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-91

STEP 4. Check the harness wires for open circuit
or short circuit between SRS-ECU connector
C-120 (terminal No.19 and 20) and side impact
sensor (LH) connector D-18 (terminal No.1 and
2).

Q: Are the harness wires between SRS-ECU

connector C-120 (terminal No.19 and 20) and side

impact sensor (LH) connector D-18 (terminal No.1
and 2) in good condition?

YES :

Go to Step 5.

NO :

Replace the harness wires between
SRS-ECU connector C-120 (terminal No.19
and 20) and side impact sensor (LH)
connector D-18 (terminal No.1 and 2).

STEP 5. Check whether the diagnosis code is
reset.

Q: Is diagnosis code B1437 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

).

AC311438 AE

C-120 (Y)

Connector: C-120

Harness side
(front view)

AC302579AC

D-18 (Y)

Connector: D-18

Centre
pillar

Front vehicle

Harness side
(front view)