Mitsubishi L200. Manual - part 594

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-47

PROBABLE CAUSES

• Damaged harness wires and connectors

• Short to the power supply 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

).

STEP2. 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 B1413 set?

YES : 

Go to Step 3.

NO : 

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

P.52B-268

).

STEP 3. Voltage 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-48

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.

(6) Connect the negative battery terminal.

(7) Turn the ignition switch to the "ON" position.

13 14 15 16 17 18 19 20

5 6 7 8 9 10 11 12

1 2

3 4

AC006257AV

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.
(8) Voltage measurement between C-131 harness 

side connector terminals 9, 10 and body earth.

OK: 1 V or less

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 B1413 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-49

Code No.B1476: Power supply voltage (IG1 (A) voltage) drops abnormally.

IG1 Power Supply Circuit System

IGNITION
SWITCH (IG1)

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

OPERATION

• The SRS-ECU is powered from the ignition 

switch (IG1).

• The SRS-ECU power is supplied from two cir-

cuits. Even if one circuit is shut off, the air bag 
can inflate.

DIAGNOSIS CODE SET CONDITIONS
This diagnosis code is set if the voltage between the 
IG1 terminals (fuse No.15 circuit) and earth is lower 
than a predetermined value for a continuous period 
of 5 seconds or more.

PROBABLE CAUSES

• Damaged wiring harnesses or connectors

• Malfunction of the SRS-ECU

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-50

DIAGNOSIS PROCEDURE

STEP 1. Check junction block fuse number 15.

AC509744

AD

Fuse No.15

Junction 
block

<LHD>

AD

AC502795

AC

Fuse No.15

Junction 
block

<RHD>

Q: Is the fuse burned out?

YES : 

Go to Step 4.

NO : 

Go to Step 2.

STEP 2. Voltage 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.
(3) Connect the negative battery terminal.
(4) Turn the ignition switch to the "ON" position.

13 14 15 16 17 18 19 20

5 6 7 8 9 10 11 12

1 2

3 4

AC203786

C-131 Harness side connector 
(rear view)

AI

CAUTION

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

side connector terminal 16 and body earth.

OK: 9 V or more.

Q: Is the check result normal?

YES : 

Go to Step 6.

NO : 

Go to Step 3.