Mitsubishi Grandis. Manual — part 1016

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-116

YES :

Replace the curtain air bag module (LH).

(Refer to

P.52B-231

).

NO :

Repair the harness wire between rear floor
harness connector G-22 (terminal No.1 and
2) and curtain air bag module (LH)
connector G-01 (terminal No.1 and 2).

STEP 9. Check whether the diagnosis code is
reset.

Q: Is diagnosis code B1450 set?

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

).

Code No.B1451: Curtain air bag module (squib) (RH) system (open-circuited in the squib circuit)

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

CONNECTOR
LOCK SWITCH

CONNECTOR
LOCK SWITCH

: CONNECTOR
CONNECTED: ON
CONNECTOR
DISCONNECTED: OFF

NOTE

CURTAIN AIR BAG
MODULE
(SQUIB) (LH)

Curtain Air Bag Module (Squib) (LH) Circuit

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-117

CAUTION

If diagnosis code B1451 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 side impact sensors and
the side air bag safing G-sensor. If the impact is over
a predetermined level, the SRS-ECU outputs an
ignition signal. At this time, if the side air bag safing
G-sensor is on, the curtain air bag module will
deploy.

DIAGNOSIS CODE SET CONDITIONS

This diagnosis code is set if curtain air bag module
squib (LH) wire(s) are open-circuited. However, if no
diagnosis code resets, the SRS warning lamp will be
switched off (diagnosis code will be retained).

PROBABLE CAUSES

• Improper connector contact

• Open circuit in the curtain air bag module (squib)

(LH) circuit

• 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 curtain air bag module (LH).
(MUT-III diagnosis code.)
(1) Disconnect the negative battery terminal.

(2) Disconnect the intermediate connector G-22

(connection between rear floor harness and floor
harness).

(3) Connect special tool dummy resistor (MB991865)

to special tool resistor harness(MB991866).

CAUTION

Do not insert a test probe into the terminal from
its front side directly as the connector contact
pressure may be weakened.
(4) Insert special tool resistor harness probe into

intermediate connector G-22 (floor harness side)
by backprobing.

(5) Connect the negative battery terminal.
(6) Erase diagnosis code memory, and then check

the diagnosis code.

Q: Is diagnosis code B1451 set?

YES :

Go to Step 4.

NO :

Go to Step 5.

AC302576AE

G-22 (R)

Connector: G-22

Floor harness
side (front view)

Third seat
belt (LH)

Second seat
belt (LH)

2 1

AC006042CA

MB991866
(Resistor harness)

G-22 Floor harness
connector

G-22 Rear floor
harness connector

MB991865
(Dummy resistor : 3

ΩΩ

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-118

STEP 4. Resistance measurement between
SRS-ECU connector C-120 (terminal No.5 and 6)
and the intermediate connector G-22 (terminal
No.1 and 2).
(1) Disconnect the negative battery terminal.

(2) Disconnect SRS-ECU connector C-120.

(3) Disconnect the intermediate connector G-22

(connection between rear floor harness and floor
harness).

CAUTION

Do not insert a test probe into the terminal from
its front side directly as the connector contact
pressure may be weakened.
(4) Resistance measurement between the following

terminals.

• SRS-ECU connector C-120 terminal No.5 and

intermediate connector G-22 (floor harness
side) terminal No.1

• SRS-ECU connector C-120 terminal No.6 and

intermediate connector G-22 (floor harness
side) terminal No.2

OK: Less than 2

Ω

Q: Are the check results normal?

YES :

Go to Step 6.

NO :

Repair the harness wire between SRS-ECU
connector C-120 (terminal No.5 and 6) and
intermediate connector G-22 (terminal No.1
and 2).

STEP 5. Resistance measurement between
intermediate connector G-22 (terminal No.1 and
2) and the curtain air bag module (LH) connector
G-01 (terminal No.1 and 2).
(1) Disconnect the negative battery terminal.

(2) Disconnect the intermediate connector G-22

(connection between rear floor harness and floor

AC311438 AE

C-120 (Y)

Connector: C-120

Harness side
(front view)

AC302576AE

G-22 (R)

Connector: G-22

Floor harness
side (front view)

Third seat
belt (LH)

Second seat
belt (LH)

2 1

AC313349

A

B

18

10

15

7

13

5

14

6

16

8

17

9

19

11

20

12

1 2

3 4

1 2

C-120
Harness side
connector
(rear view)

G-22 Floor harness
side connector
(rear view)

AB

AC302576AE

G-22 (R)

Connector: G-22

Floor harness
side (front view)

Third seat
belt (LH)

Second seat
belt (LH)

2 1

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-119

harness connector).

(3) Disconnect curtain air bag module (LH)

connector G-01, and measure at the wiring
harness side. For connector G-01, 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.

(4) Connect G-01 harness side connector to special

tool resistor harness (MB991884).

CAUTION

Do not insert a test probe into the terminal from
its front side directly as the connector contact
pressure may be weakened.
(5) Resistance measurement between the following

terminals.

• Intermediate connector (rear floor harness

side) G-22 terminal No.2 and special tool
terminal No.2

• Intermediate connector (rear floor harness

side) G-22 terminal No.1 and special tool
terminal No.1

OK: Less than 2

Ω

Q: Is the check result normal?

YES :

Replace the curtain air bag module (LH).

(Refer to

P.52B-231

).

NO :

Repair the harness wire between
intermediate connector G-22 (terminal No.1
and 2) and curtain air bag module (LH)
connector G-01 (terminal No.1 and 2).

STEP 6. Check whether the diagnosis code is
reset.

Q: Is diagnosis code No.B1451 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

).

AC303223

AC

G-01 (B)

Connector: G-01

Harness side
(front view)

Roof centre duct

AC208384AN

G-01
Curtain air bag
module connector

Flat-tip screw
driver

Locking button

G-01
Harness side
connector

AC201287BJ

G-01

Harness side
connector

MB991884

1 2

2

1

AC303985AC

G-22 Rear floor harness
connector (rear view)

<G-01
Harness
connector>
Special tool
MB991884
(front view)