Mitsubishi L200. Manual — part 646

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-255

SYMPTOM PROCEDURES <VEHICLES
WITH SIDE-AIRBAG AND CURTAIN
AIR BAG>

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

FRONT SIDE

AC801154

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

DIAGNOSIS
CONNECTOR

SRS-ECU Power Supply Circuit

AC

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-256

DIAGNOSIS PROCEDURE

STEP 1. Wiring harnesses check between SRS-
ECU connector C-154 (terminal No.38) 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)

AC801404

AJ

Connector: C-154

C-154 (Y)

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-154
(1) Disconnect the negative battery terminal.

AC801404

AJ

Connector: C-154

C-154 (Y)

Harness side
connector
(rear view)

(2) Disconnect SRS-ECU connector C-154 and

measure at the wiring harness side.

AC800962 CG

C-154 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.
(3) Check for continuity between terminal 41 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-154
(terminal No.41) and earth, and repair if
necessary.

POST-COLLISION DIAGNOSIS

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-257

STEP 3. Voltage measurement the power supply
circuit to the SRS-ECU connector C-154.
(1) Disconnect the negative battery terminal.

AC801404

AJ

Connector: C-154

C-154 (Y)

Harness side
connector
(rear view)

(2) Disconnect SRS-ECU connector C-154 and

measure at the wiring harness side.

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

AC800963 AY

C-154 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) Voltage measurement between terminals 37, 43

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-158
(terminal No.37, 43) 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

).

POST-COLLISION DIAGNOSIS

M1524001102353

Whether or not the air bags have deployed, check
and service the vehicle after collision as follows:

POST-COLLISION DIAGNOSIS

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-258

SRS-ECU MEMORY CHECK

AC509179

AB

Diagnosis

connector

MB991827

MB991824

MB991910

<LH drive vehicles>

CAUTION

Refer to that the ignition switch is "LOCK" (OFF)
when connecting or disconnecting M.U.T.-III.
1. Connect the M.U.T.-III to the diagnosis connector

(Refer to GROUP 00, Diagnosis Function).

2. Read (and write down) all displayed diagnosis

codes (Refer to

P.52B-12

).

NOTE: If battery power supply has been shut
down by the collision, the M.U.T.-III cannot com-
municate with the SRS-ECU. Check and, repair if
necessary, the instrument panel wiring harness
before the next job.

3. Use the M.U.T.-III to read the data list (how long

trouble(s) have continued and how often memory
have been erased).

Data list

No.

Data list Item

Applicability

01

Failure continuation time 1

Maximum time to be stored: 9,999 minutes
(approximately 7 days)

02

Failure continuation time 2

03

Elimination times

Maximum time to be stored: 250 times

4. Erase the diagnosis codes and after waiting 5

seconds or more read (and write down) all
displayed diagnosis codes.

REPAIR PROCEDURE

WHEN FRONT AIR BAGS DEPLOY IN A COLLI-
SION.
1. Replace the following parts with new ones.

• Front impact sensor (Refer to

P.52B-263

).

• SRS-ECU (Refer to

P.52B-266

).

• Driver’s air bag modules (Refer to

P.52B-268

).

• Passenger’s (front) air bag modules (Refer to

P.52B-268

).

• Seat belt with pre-tensioner (Refer to

P.52B-284

).

2. Check the following parts and replace if there are

any malfunctions.

• Clock spring (Refer to

P.52B-268

).

• Steering wheel, steering column and shaft

assembly

(1) Check the wiring harness (built into the

steering wheel) and connectors for damage,
and terminals for deformation.

(2) Install the air bag module to check fit or

alignment with the steering wheel.

(3) Check the steering wheel for noise, binds or

difficult operation and excessive free play.

(4) Check the steering column shaft shock

absorbing mechanism (Refer to GROUP 37,
On-vehicle Service ).

• Instrument panel (Refer to GROUP 52A, Instru-

ment panel assembly ).

• Passenger’s air bag cut off switch (Refer to

P.52B-287

).