Mitsubishi L200. Manual — part 588

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-23

STEP 4. Check the diagnosis code by connecting
a dummy resistor. (M.U.T.-III diagnosis code)
(1) Disconnect the negative battery terminal.

AC501669

A

C-303 Air bag
module connector

AB

(2) By sliding the A section (in the figure) of air bag

module connector C-303 in the arrow direction,
disconnect the connector.

AC303006AF

C-303 Air bag

module

connector

MB991865

(Dummy

resistor : 3 )

MB991866
(Resistor 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 (MB991866) into clock spring

side air bag module connector C-303 by
backprobing.

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

diagnosis code.

Q: Is diagnosis code B1400 set?

YES :

Go to Step 5.

NO :

Replace the driver's air bag module (Refer
to

P.52B-268

).

STEP 5. Check the diagnosis code by connecting
a dummy resistor. (M.U.T.-III diagnosis code)
(1) Disconnect the negative battery terminal.

AC903858AD

Connector: C-305 <LHD>

Harness side
connector
(front view)

C-305 (Y)

AC903869AD

Connector: C-305 <RHD>

Harness side
connector
(front view)

C-305 (Y)

C-305

(2) Disconnect the clock spring connector C-305.

AC303587AN

C-305 Clock spring

connector

MB991865
(Dummy resistor: 3 )

MB991866

(Resistor harness)

(Rear view)

(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 clock spring

harness side connector C-305 (terminal No.3 and
4) by backprobing.

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

diagnosis code.

Q: Is diagnosis code B1400 set?

YES :

Go to Step 6.

NO :

Replace the clock spring (Refer to

P.52B-

268

).

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-24

STEP 6. 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.

AC903858AD

Connector: C-305 <LHD>

Harness side
connector
(front view)

C-305 (Y)

AC903869AD

Connector: C-305 <RHD>

Harness side
connector
(front view)

C-305 (Y)

C-305

DANGER

To prevents the air bag from deploying unin-
tentionally, disconnect the clock spring con-
nector C-305 to short the squib circuit.

(3) Disconnect the clock spring connector C-305.

AC100391

Section
A - A

C-131 Harness side connectors
(front view)

Cable tie

Short spring

4 mm or more

Terminal

A

BE

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 11, 12 and the short spring to
release the short spring.

AC800962 BE

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.
(5) Resistance measurement between C-131

harness side connector terminals 11 and 12.

OK: Open circuit

Q: Is the check result normal?

YES :

Go to Step 7.

NO :

Repair the harness wires between SRS-
ECU connector C-131 (terminal No.11 and
12) and clock spring connector C-305
(terminal No.3 and 4).

STEP 7. Check whether the diagnosis code is
reset.

Q: Is diagnosis code B1400 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-25

Code No.B1401: Driver's air bag module (squib) system (open-circuited in the squib circuit)

AC806117

Driver's Air Bag Module (Squib) Circuit

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

CONNECTOR
LOCK SWITCH

CONNECTOR
LOCK SWITCH

CLOCK SPRING

SRS-ECU

CONNECTOR
LOCK SWITCH

NOTE

: CONNECTOR COUPLED: ON
CONNECTOR UNCOUPLED: OFF

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

AB

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

via the clock spring to inflate the air bag.

DIAGNOSIS CODE SET CONDITIONS
This diagnosis code is set if driver’s air bag squib
wire(s) are open-circuited.

PROBABLE CAUSES

• Open circuit in the clock spring

• Open circuit due to improper neutral position of

the clock spring

• Open circuit in the driver's air bag module (squib)

circuit

• Disengaged driver's air bag module (squib) con-

nector

• Improper connector contact

• Malfunction of the SRS-ECU

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-26

DIAGNOSIS PROCEDURE

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

AC501669

A

C-303 Air bag
module connector

AB

(2) By sliding the A section (in the figure) of air bag

module connector C-303 in the arrow direction,
disconnect the connector.

AC303006AF

C-303 Air bag

module

connector

MB991865

(Dummy

resistor : 3 )

MB991866
(Resistor 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 (MB991866) into clock spring

side air bag module connector C-303 by
backprobing.

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

diagnosis code.

Q: Is diagnosis code B1401 set?

YES :

Go to Step 2.

NO :

Replace the driver's air bag module (Refer
to

P.52B-268

).

STEP 2. Check the clock spring. (M.U.T.-III
diagnosis code)
(1) Disconnect the negative battery terminal.

AC903858AD

Connector: C-305 <LHD>

Harness side
connector
(front view)

C-305 (Y)

AC903869AD

Connector: C-305 <RHD>

Harness side
connector
(front view)

C-305 (Y)

C-305

(2) Disconnect the clock spring connector C-305.

AC303587AN

C-305 Clock spring

connector

MB991865
(Dummy resistor: 3 )

MB991866

(Resistor harness)

(Rear view)

(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 clock spring

harness side connector C-305 (terminal No.3 and
4) by backprobing.

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

diagnosis code.

Q: Is diagnosis code B1401 set?

YES :

Go to Step 3.

NO :

Replace the clock spring (Refer to

P.52B-

268

).