Mitsubishi L200. Manual - part 645

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-251

disconnect the connector.

AC801566

Section
A - A

C-153 Harness side connectors
(front view)

Cable tie

Terminal

 7 mm or more

AG

Short spring

A

A

CAUTION

Insert an insulator such as a cable tie to a depth 
of 7 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 5, 6 and the short spring to 
release the short spring.

(5) Connect the negative battery terminal.

(6) Turn the ignition switch to the "ON" position,

AC800963AX

C-153 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.
(7) Voltage measurement between C-153 harness 

side connector terminals 5, 6 and body earth.

OK: 1 V or less

Q: Is the check result normal?

YES : 

Go to Step 3.

NO : 

Repair the harness wires between SRS-
ECU connector C-153 (terminal No.5 and 6) 
and the seat belt pre-tensioner (passenger's 
side) connector D-23 <LHD>, D-15 <RHD> 
(terminal No.1 and 2)

STEP 3. Check whether the diagnosis code is 
reset.

Q: Is diagnosis code B1612 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 ).

CHECK CHART FOR TROUBLE SYMPTOMS

M1524003401409

Trouble

Inspection procedure No.

Reference page

Communication with M.U.T.-III is not possible 
(Communication with engine control systems is 
not possible).

−

GROUP 13A, 
Troubleshooting 

Communication with M.U.T.-III is not possible 
(Communication is not possible with SRS).

1

P.52B-252

 <vehicles 

without side-airbag and 
curtain air bag>, 

P.52B-255

 <vehicles 

with side-airbag and 
curtain air bag>

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-252

SYMPTOM PROCEDURES <VEHICLES 
WITHOUT SIDE-AIRBAG AND 
CURTAIN AIR BAG>

  Inspection Procedure 1: Communication with M.U.T.-III is not possible (Communication is not 
possible with SRS).

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

FRONT SIDE

DIAGNOSIS
CONNECTOR

SRS-ECU Power Supply Circuit

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.

• The SRS system diagnosis can be done by con-

necting M.U.T.-III to the diagnosis connector.

COMMENTS ON TROUBLE SYMPTOM
If communication is not possible with the SRS only, 
the cause is probably an open circuit in the diagnosis 
output circuit of the SRS or in the power circuit 
(including earth circuit).

PROBABLE CAUSES

• Damaged wiring harnesses or connectors

• Malfunction of the SRS-ECU

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-253

DIAGNOSIS PROCEDURE

STEP 1. Wiring harnesses check between SRS-
ECU connector C-131 (terminal No.20) and 
diagnosis connector C-22 (terminal No.7).

AC903856BO

Connector: C-22 <LHD>

C-22 (B)

Harness side 
(Front side)

AC903868

CH

Connector: C-22 <RHD>

C-22 (B)

Harness side 
(Front side)

AC501670

AB

C-131 (Y)

Connector: C-131

Harness side 
connector 
(rear view)

• Check the wiring harness for open circuit.

Q: Is the check results normal?

YES : 

Go to Step 2.

NO : 

Repair the wiring harness.

STEP 2. Resistance measurement the earth 
circuit to 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 and 

measure at the wiring harness side.

AC505128

1314151617181920

5 6 7 8 9 101112

1 2

3 4

C-131 Harness side connector (rear view)

AB

CAUTION

Do not insert a test probe into the terminal from 
its front side directly as the connector contact 
pressure may be weakened.
(3) Check for continuity between terminal 18 and 

body earth.

OK: Continuity (Less than 2 

Ω)

Q: Is the check result normal?

YES : 

Go to Step 3.

NO : 

Check the harness wire for open circuit 
between SRS-ECU connector C-131 
(terminal No.18) and earth, and repair if 
necessary.

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-254

STEP 3. Voltage measurement the power supply 
circuit to 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 and 

measure at the wiring harness side.

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

AC006265

13 14 15 16 17 18 19 20

5 6 7 8 9 10 11 12

1 2

3 4

C-131 Harness side 
connector (rear view)

AV

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 terminals 13, 16 

and body earth.

OK: 9 V or more

Q: Is the check result normal?

YES : 

Go to Step 4.

NO : 

Check the harness wires for open or short 
circuit between SRS-ECU connector C-131 
(terminal No.13, 16) and ignition switch, and 
repair if necessary. 

STEP 4. Retest the system.

Q: Does the M.U.T.-III communicate normally with the 

SRS system?
YES : 

An intermittent malfunction is suspected 

(Refer to GROUP 00, How to Cope with 
Intermittent Malfunction ).

NO : 

Replace the SRS-ECU (Refer to 

P.52B-

266

).