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>

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AC310628AK

Connector: C-124 <RHD>

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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

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AC310628AK

Connector: C-124 <RHD>

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