Mitsubishi Grandis. Manual - part 1029

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-168

DIAGNOSIS CODE SET CONDITIONS

• This diagnosis code is set under one of the 

following cases while the SRS-ECU is monitoring 
the passenger’s air bag off indicator lamp drive 
circuit:

• When a short circuit occurs in the 

passenger’s air bag off indicator lamp drive 
circuit.

• When a malfunction is detected in the output 

transistor inside the SRS-ECU.

PROBABLE CAUSES

• Damaged wiring harnesses or connectors

• 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. Connector check SRS-ECU connector 
C-119.

Q: Is SRS-ECU connector C-119 good condition? 

YES : 

Go to Step 3.

NO : 

Engage the connector correctly. Then go to 
Step 4 .

STEP 3. Check the harness for short circuit 
between passenger’s air bag off indicator lamp 
C-25 (terminal No.3) and SRS-ECU connector 
C-119 (terminal No.21).

Q: Are the harness wires between SRS-ECU 

connector C-119 (terminal No.21) and the 
passenger’s air bag off indicator lamp C-25 
(terminal No.3) in good condition?

YES : 

Go to Step 4 .

NO : 

Repair the harness wires. Then go to Step 4 
.

STEP 4. Check whether the diagnosis code is 
reset.

Q: Is diagnosis code B1488 set?

AC311438 AD

C-119 (Y)

Connector: C-119

Harness side
(front view)

AC310613

BI

Connector: C-25 <LHD>

Harness side

AC310631BE

Connector: C-25 <RHD>

Harness side

AC311438 AD

C-119 (Y)

Connector: C-119

Harness side
(front view)

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-169

YES : 

Replace the SRS-ECU (Refer to 

P.52B-223

).

NO : 

The procedure is complete (If no 
malfunctions are found in all steps, an 
intermittent malfunction is suspected). Refer 
to GROUP 00, How to Use 
Troubleshooting/Inspection Service Points 

P.00-5

. 

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-170

Code No.B1489: Passenger’s air bag off indicator lamp drive circuit system fault 1 (Lamp does not 
Illuminate).

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

IGNITION
SWITCH (IG1)

PASSENGER'S
AIR BAG OFF
INDICATOR LAMP

RELAY
BOX

TAIL LAMP
RELAY

FRONT-ECU

Air Bag Off Indicator Lamp Drive Circuit <LH drive vehicles>

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-171

CAUTION

If diagnosis code B1489 is set in the SRS-ECU, 
always diagnose the CAN main bus line.

OPERATION

• Power for the passenger’s air bag off indicator 

lamp is supplied from the ignition switch (IG1).

• The passenger’s air bag off indicator lamp 

illuminates when the ignition switch is turned to 
the "ON" position and goes out after 
approximately 7 seconds if there is not a 
malfunction in the SRS system.

• If a failure occurs in the system, the SRS-ECU 

will stop sending that SRS warning lamp "OFF" 
signal, thus causing the combination meter to 
illuminate the SRS warning lamp.

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

IGNITION
SWITCH (IG1)

PASSENGER'S
AIR BAG OFF
INDICATOR LAMP

RELAY
BOX

TAIL LAMP
RELAY

FRONT-ECU

Air Bag Off Indicator Lamp Drive Circuit <RH drive vehicles>