Mitsubishi Grandis. Manual — part 1002

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-60

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 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 front impact sensor (LH)
power supply circuit. Voltage measurement at the
front impact sensor (LH) connector A-22.
(1) Disconnect the negative battery terminal.

(2) Disconnect front impact sensor (LH) connector

A-22, 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 A-22 harness side

connector terminal 1 and body earth.

OK: 9 V or more

Q: Is the check result normal?

YES :

Replace the front impact sensor (LH).

(Refer to

P.52B-220

).

NO :

Go to Step 4.

AC311405AC

A-22 (Y)

Connector: A-22

Harness side
(front view)

AC311097

A-22 Harness side
connector (rear view)

AE

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-61

STEP 4. Check the harness wires for open circuit
or short circuit between SRS-ECU connector
C-119 (terminal No.38 and 39) and front impact
sensor (LH) connector A-22 (terminal No.1 and
2).

NOTE:

After inspecting intermediate connector C-124
inspect the wiring harness. If the intermediate
connector C-124 is damaged, repair or replace it.

Q: Are the harness wires between SRS-ECU

connector C-119 (terminal No.38 and 39) and front
impact sensor (LH) (front) connector A-22 (terminal
No.1 and 2) in good condition?

YES :

Go to Step 5.

NO :

Repair the harness wires between
SRS-ECU connector C-119 (terminal No.38
and 39) and front impact sensor (LH)
connector A-22 (terminal No.1 and 2).

STEP 5. Check whether the diagnosis code is
reset.

Q: Is diagnosis code B1417 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 AD

C-119 (Y)

Connector: C-119

Harness side
(front view)

AC311405AC

A-22 (Y)

Connector: A-22

Harness side
(front view)

AC310613

AH

Connector: C-124 <LHD>

9

21

33

35

24

12

3 4

7

8

5 6

39

28

41

30

18

4243

31

1920

32

40

29

1617

38

27

15

37

36

26

14

13

25

2

1

34

23

11

10

22

AC310628AK

Connector: C-124 <RHD>

9

21

33

35

24

12

3 4

7

8

5 6

39

28

41

30

18

4243

31

1920

32

40

29

1617

38

27

15

37

36

26

14

13

25

2

1

34

23

11

10

22

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-62

Code No.B1418: Front Impact Sensor (LH) (Squib) for Power Supply Circuit
Code No.B1419: Front Impact Sensor (LH) (Squib) for Communication System

CAUTION

If diagnosis code B1418 or B1419 is set in the
SRS-ECU, always diagnose the CAN main bus
line.

OPERATION

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

DIAGNOSIS CODE SET CONDITIONS

These diagnosis codes are set if communication
between the front impact sensor (LH) and the
SRS-ECU is not possible or faulty.

PROBABLE CAUSES

• Damaged wiring harnesses or connectors

• Malfunction of the front impact sensor (LH)

• 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 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?

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

SRS-ECU

FRONT IMPACT
SENSOR (LH)

FRONT IMPACT
SENSOR (RH)

Front Impact Sensor Circuit

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-63

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 front impact sensor (LH).
(MUT-III diagnosis code.)
(1) Disconnect the negative battery terminal.
(2) Replace the front impact sensor (LH) with the

front impact sensor (RH).

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

the diagnosis code.

Q: Is diagnosis code B1408 or B1409 set?

YES :

Replace the front impact sensor (LH) with a

new one. (Refer to

P.52B-236

). Go to Step

5.

NO :

Go to Step 4.

STEP 4. Check the harness wires for open circuit
or short circuit between SRS-ECU connector
C-119 (terminal No.38 and 39) and front impact
sensor (LH) connector A-22 (terminal No.1 and
2).

NOTE:

After inspecting intermediate connector C-124
inspect the wiring harness. If the intermediate
connector C-124 is damaged, repair or replace it.

Q: Is the check result normal?

AC311438 AD

C-119 (Y)

Connector: C-119

Harness side
(front view)

AC311405AC

A-22 (Y)

Connector: A-22

Harness side
(front view)

AC310613

AH

Connector: C-124 <LHD>

9

21

33

35

24

12

3 4

7

8

5 6

39

28

41

30

18

4243

31

1920

32

40

29

1617

38

27

15

37

36

26

14

13

25

2

1

34

23

11

10

22

AC310628AK

Connector: C-124 <RHD>

9

21

33

35

24

12

3 4

7

8

5 6

39

28

41

30

18

4243

31

1920

32

40

29

1617

38

27

15

37

36

26

14

13

25

2

1

34

23

11

10

22