Mitsubishi Grandis. Manual - part 1019

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-128

Code No.B1458: Side-Impact sensor (Rear) (LH) (Squib) for Power Supply Circuit
Code No.B1459: Side-Impact sensor (Rear) (LH) (Squib) or Communication System

CAUTION

If diagnosis code B1448 or B1449 is set in the 
SRS-ECU, always diagnose the CAN main bus 
line.

OPERATION

The side impact sensor (Rear) includes an analogue 
G sensor and CPU, etc. The CPU monitors the 
analogue G sensor output signal. If the CPU judges 
that the curtain air bags should be deployed, it sends 
a fire signal to the SRS-ECU to deploy the curtain air 
bags. In addition, the CPU diagnoses the internal 
components of the side impact sensor (Rear). 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 side impact sensor (Rear) (LH) and the 
SRS-ECU is not possible or communication is faulty.

PROBABLE CAUSES

• Damaged wiring harnesses or connectors

• Malfunction of the side impact sensor (Rear) (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?

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 (Rear) (LH). 
(MUT-III diagnosis code.)
(1) Disconnect the negative battery terminal.

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 (REAR: LH)

SRS-ECU

Side Impact Sensor (Rear) (LH) Circuit

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-129

(2) Replace the side impact sensor (Rear) (LH) with 

the side impact sensor (Rear) (RH).

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

diagnosis code.

Q: Is diagnosis code B1458 or B1459 set?

YES : 

Replace the side impact sensor (Rear) (LH) 

with a new one. (Refer to 

P.52B-236

). Then 

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-120 (terminal No.15 and 16) and side impact 
sensor (Rear) (LH) connector D-12 (terminal No.1 
and 2).

Q: Is the check result normal? 

YES : 

Go to Step 5.

NO : 

Repair the harness wires between 
SRS-ECU connector C-120 (terminal No.15 
and 16) and side impact sensor (Rear) (LH) 
connector D-12 (terminal No.1 and 2).

STEP 5. Check whether the diagnosis code is 
reset.

Q: Is diagnosis code B1458 or B1459 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)

AC311614 AD

D-12 (Y)

Connector: D-12

Harness side
(front view)

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-130

Code No.B1460: Seat Belt Pre-Tensioner (RH) (Squib) System Fault 1 (Short Circuit between 
Terminals of the Squib Circuit)

CAUTION

If diagnosis code B1460 is set in the SRS-ECU, 
always diagnose the CAN main bus line.

OPERATION

The SRS-ECU judges how severe a collision is by 
detecting signals from the front impact sensors and 
the front air bag analogue G-sensor. If the impact is 
over a predetermined level, the SRS-ECU sends an 
ignition signal. At this time, if the front air bag safing 
G-sensor is on, the pre-tensioner will deploy. 

DIAGNOSIS CODE SET CONDITIONS

This diagnosis code is set if there is abnormal 
resistance between the input terminals of the seat 
belt pre-tensioner (RH) (squib).

PROBABLE CAUSES

• Improper engaged connector or defective short 

spring*

• Short circuit between the seat belt pre-tensioner 

(RH) (squib) circuit terminals

• Damaged connector(s)

• Malfunction of the SRS-ECU

NOTE: *: The squib circuit connectors integrate a 
"short" spring (which prevents the seat belt 
pre-tensioner from deploying unintentionally due to 
static electricity by shorting the positive wire to the 
earth wire in the squib circuit when the connectors 
are disconnected) (Refer to 

P.52B-5

). Therefore, if 

connector C-118 or D-32 is damaged or improperly 
engaged, the short spring may not be released when 
the connector is connected.

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

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

SEAT BELT
PRETENSIONER
(RH)

SRS-ECU

CONNECTOR
LOCK SWITCH

CONNECTOR
LOCK SWITCH

: CONNECTOR
  CONNECTED: ON
  CONNECTOR
  DISCONNECTED: OFF

NOTE

Seat Belt Pre-Tensioner (RH) (Squib) Circuit

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-131

(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. MUT-III diagnosis code

CAUTION

To prevent damage to MUT-III MB991958, always 
turn the ignition switch to the "LOCK" (OFF) 
position before connecting or disconnecting 
MUT-III MB991958.
(1) Turn the ignition switch to the "ON" position.
(2) Check if the diagnosis code is set.
(3) Turn the ignition switch to the "LOOK (OFF)" 

position.

Q: Is diagnosis code B1519 set?

YES : 

Go to Step 4.

NO : 

Go to Step 5.

STEP 4. Connector lock check: SRS-ECU 
connector C-118 (MUT-III diagnosis code)
(1) Disconnect the negative battery terminal.

(2) Disconnect the connectors C-118 and then 

reconnect them.

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

diagnosis code.

Q: Is diagnosis code B1460 set?

YES : 

Go to Step 5.

NO : 

The procedure is complete. It is assumed 
that diagnosis code B1460 set as connector 
C-118 was engaged improperly.

STEP 5. Connector lock check: SRS-ECU 
connector C-118 and seat belt pre-tensioner (RH) 
connector D-32 (MUT-III diagnosis code)
(1) Disconnect the negative battery terminal.

(2) Disconnect connectors C-118 and D-32, and then 

reconnect them. For connector D-32, use a 
flat-tipped screwdriver to unlock the locking 
button at the harness side connector by 
withdrawing it toward you in two stages, and then 
disconnect the connector.

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

diagnosis code.

Q: Is diagnosis code B1460 set?

YES : 

Go to Step 6.

NO : 

The procedure is complete. It is assumed 
that diagnosis code B1460 set as connector 
C-118 or D-32 was engaged improperly.

AC311438 AC

C-118 (Y)

Connector: C-118

Harness side
(front view)

AC311438 AC

C-118 (Y)

Connector: C-118

Harness side
(front view)

AC302394AC

 D-32 (B)

Connector: D-32

Centre
pillar

Front vehicle

Harness side
(front view)

AC103556AX

Locking button

Flat-tip screw
driver

D-32 Harness
side connector

D-32 Seat belt
pre-tensioner (RH)
connector