Mitsubishi Grandis. Manual - part 997

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-40

STEP 4. Check the harness wires for open circuit 
or short circuit between SRS-ECU connector 
C-119 (terminal No.47 and 48) and front impact 
sensor (RH) connector A-30 (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.47 and 48) and front 
impact sensor (RH) (front) connector A-30 
(terminal No.1 and 2) in good condition?

YES : 

Go to Step 5.

NO : 

Replace the harness wires between 
SRS-ECU connector C-119 (terminal No.47 
and 48) and front impact sensor (RH) 
connector A-30 (terminal No.1 and 2).

STEP 5. Check whether the diagnosis code is 
reset.

Q: Is diagnosis code B1407 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)

AC311404 AB

A-30 (Y)

Connector: A-30

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-41

Code No.B1408: Front Impact Sensor (RH) (Squib) for Power Supply Circuit
Code No.B1409: Front Impact Sensor (RH) (Squib) for Communication System

CAUTION

If diagnosis code B1408 or B1409 is set in the 
SRS-ECU, always diagnose the CAN main bus 
line.

OPERATION

The front 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 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 (RH) and the 
SRS-ECU is not possible or faulty.

PROBABLE CAUSES

• Damaged wiring harnesses or connectors

• Malfunction of the front impact sensor (RH)

• 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-42

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

front impact sensor (LH).

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

the diagnosis code.

Q: Is diagnosis code B1418 or B1419 set?

YES : 

Replace the front impact sensor (RH) 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.47 and 48) and front impact 
sensor (RH) connector A-30 (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)

AC311404 AB

A-30 (Y)

Connector: A-30

Harness side
(front view)

AC310613

AH

Connector: C-124 <LHD>

9

21

33

35

24

12

3 4

7

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5 6

39

28

41

30

18

4243

31

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37

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1

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AC310628AK

Connector: C-124 <RHD>

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3 4

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5 6

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TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-43

YES : 

Go to Step 5.

NO : 

Repair the harness wires between 
SRS-ECU connector C-119 (terminal No.47 
and 48) and front impact sensor (RH) 
connector A-30 (terminal No.1 and 2).

STEP 5. Check whether the diagnosis code is 
reset.

Q: Is diagnosis code B1408 or B1409 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.B1410: Passenger’s (Front) Air Bag Module (1st Squib) System Fault 1 (Short Circuit 
between Terminals of the Squib Circuit)
Code No.B1490: Passenger’s (Front) Air Bag Module (2nd Squib) System Fault 1 (Short Circuit 
between Terminals of the Squib Circuit)

AIR BAG MODULE 
(SQUIB) 
(PASSENGER'S SIDE)

SRS-ECU

CONNECTOR
LOCK SWITCH

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

: CONNECTOR
  CONNECTED: ON
  CONNECTOR
  DISCONNECTED: OFF

NOTE

Passenger's (Front) Air Bag Module (1st Squib and 2nd Squib) Circuit