Mitsubishi L200. Manual — part 593

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-43

Code No.B1412: Passenger's (front) air bag module (squib) system (short-circuited to the earth)

IND

AC805767

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

PASSENGER'S AIR BAG
CUT OFF SWITCH

SRS-ECU

Wire colour code
B : Black LG : Light green G : Green L : Blue W : White Y : Yellow SB : Sky blue
BR : Brown O : Orange GR : Grey R : Red P : Pink V : Violet PU : Purple

J/B
(FUSE )

PASSENGER'S
AIR BAG
CUT OFF
INDICATOR

CONNECTOR LOCK SWITCH

CONNECTOR COUPLED: ON

CONNECTOR UNCOUPLED: OFF

NOTE

Passenger's (Front) Air Bag Module (Squib) Circuit

AC

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 SRS air
bag will inflate.

• The ignition signal is input to the air bag module

to inflate the air bag.

DIAGNOSIS CODE SET CONDITIONS
This diagnosis code is set if the passenger's (front)
air bag squib wire(s) are short-circuited to the earth.

PROBABLE CAUSES

• Damaged harness wires and connectors

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-44

• Short to the earth in the passenger's (front) air

bag module (squib) harness

• Malfunction of the passenger’s air bag cut off

switch

• Malfunction of the SRS-ECU

DIAGNOSIS PROCEDURE

STEP 1. Check the passenger’s air bag cut off
switch.
Check the passenger's air bag cut off switch (Refer
to

P.52B-288

).

Q: Is the check result normal?

YES :

Go to Step 2.

NO :

Replace passenger’s air bag cut off switch
(Refer to

P.52B-287

).

STEP 2. Check the diagnosis code by connecting
a dummy resistor. (M.U.T.-III diagnosis code)
(1) Disconnect the negative battery terminal.

AC509788

C-02 (R)

AC

Glove box striker

2 1

Harness side
connector
(front view)

Lock
lever

Connector: C-02

(2) Disconnect passenger’s (front) air bag module

connector C-02. Pull up the harness side lock
lever with a nail and disconnect the connector
lock.

AC300956 AP

MB991865
(Dummy resistor: 3 )

MB991866

(Resistor harness)

C-02 Passenger's

(front) air bag

module connector

C-02 Harness side

connector

(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 (MB991866) into the harness

side connector C-02 by backprobing.

(5) Check that the passenger's air bag cut off switch

is "ON" position.

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

diagnosis code.

Q: Is diagnosis code B1412 set?

YES :

Go to Step 3.

NO :

Replace the passenger's (front) air bag
module (Refer to

P.52B-268

).

STEP 3. Resistance measurement at the SRS-
ECU connector C-131.
(1) Disconnect the negative battery terminal.

AC501670

AB

C-131 (Y)

Connector: C-131

Harness side
connector
(rear view)

(2) Disconnect SRS-ECU connector C-131.

AC509788

C-02 (R)

AC

Glove box striker

2 1

Harness side
connector
(front view)

Lock
lever

Connector: C-02

DANGER

To prevents the air bag from deploying unin-
tentionally, disconnect the passenger’s
(front) air bag module connector C-02 to
short the squib circuit.

(3) Disconnect passenger’s (front) air bag module

connector C-02. Pull up the harness side lock
lever with a nail and disconnect the connector

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-45

lock.

AC006036

Section
A - A

C-131Harness side connectors
(front view)

Cable tie

Short spring

4 mm or more

Terminal

BC

A

A

CAUTION

Insert an insulator such as a cable tie to a depth
of 4 mm or more, otherwise the short spring will
not be released.
(4) Insert a cable tie [3 mm wide, 0.5 mm thick]

between terminals 9, 10 and the short spring to
release the short spring.

(5) Check that the passenger's air bag cut off switch

is "ON" position.

AC006258

13 14 15 16 17 18 19 20

5 6 7 8 9 10 11 12

1 2

3 4

AV

C-131 Harness
side connector
(rear view)

CAUTION

Do not insert a test probe into the terminal from
its front side directly as the connector contact
pressure may be weakened.
(6) Resistance measurement between C-131

harness side connector terminals 9, 10 and body
earth.

OK: Open circuit

Q: Is the check result normal?

YES :

Go to Step 4.

NO :

Repair the harness wires between SRS-
ECU connector C-131 (terminal No.9 and
10) and passenger's (front) air bag module
connector C-02 (terminal No.1 and 2).

STEP 4. Check whether the diagnosis code is
reset.

Q: Is diagnosis code B1412 set?

YES :

Replace the SRS-ECU (Refer to

P.52B-

266

).

NO :

An intermittent malfunction is suspected
(Refer to GROUP 00, How to Cope with
Intermittent Malfunction ).

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-46

Code No.B1413: Passenger's (front) air bag module (squib) system (short-circuited to the power
supply)

IND

AC805767

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

PASSENGER'S AIR BAG
CUT OFF SWITCH

SRS-ECU

Wire colour code
B : Black LG : Light green G : Green L : Blue W : White Y : Yellow SB : Sky blue
BR : Brown O : Orange GR : Grey R : Red P : Pink V : Violet PU : Purple

J/B
(FUSE )

PASSENGER'S
AIR BAG
CUT OFF
INDICATOR

CONNECTOR LOCK SWITCH

CONNECTOR COUPLED: ON

CONNECTOR UNCOUPLED: OFF

NOTE

Passenger's (Front) Air Bag Module (Squib) Circuit

AC

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 SRS air

bag will inflate.

• The ignition signal is input to the air bag module

to inflate the air bag.

DIAGNOSIS CODE SET CONDITIONS
This diagnosis code is set if the passenger's (front)
air bag squib wire(s) are short-circuited to the power
supply.