Mitsubishi Montero (2004+). Manual — part 1208

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-167

CIRCUIT OPERATION
The side impact sensor includes an analog G sensor
and CPU, etc. The CPU monitors the analog G sen-
sor output signal. If the CPU judges that the side-air-
bags should be deployed, it sends a fire signal to the
SRS-ECU to deploy the side-airbags. Besides that,
the CPU diagnoses the internal components of the
side impact sensor. If a malfunction occurs, it
requests the SRS-ECU to set a diagnostic trouble
code.

.

DTC SET CONDITIONS
These DTC are set if communication between the
side impact sensor (LH) and the SRS-ECU is not
possible or communication is faulty.

.

TROUBLESHOOTING HINTS

• Damaged wiring harnesses or connectors

• Malfunction of the side impact sensor (LH)

• Malfunction of the SRS-ECU

.

DIAGNOSIS

Required Special Tool:

• MB991958: Scan Tool (MUT-III Sub Assembly)

• MB991824: Vehicle Communication Interface (V.C.I.)

• MB991827: MUT-III USB Cable

• MB991911: MUT-III Main Harness B (Vehicles without

CAN communication system)

STEP 1. Check the side impact sensor (LH). (Using scan
tool MB991958, read the diagnostic trouble code).
(1) Disconnect the negative battery terminal.
(2) Replace the side impact sensor (LH) with the side impact

sensor (RH).

(3) Connect the negative battery terminal.
(4) Erase diagnostic trouble code memory, and then check the

diagnostic trouble code.

Q: Is DTC 89 or 96 set?

YES : Replace the side impact sensor (LH) with a new one

(Refer to

P.52B-227

). Then go to Step 3.

NO : Go to Step 2.

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-168

STEP 2. Check the harness wires for open circuit or short
circuit between SRS-ECU connector E-07 (terminal No.34
and 36) and side impact sensor (LH) connector F-13
(terminal No.1 and 2).

NOTE: After inspecting intermediate connector E-19 inspect
the wiring harness. If the intermediate connector E-19 is dam-
aged, repair or replace it (Refer to GROUP 00E, Harness Con-
nector Inspection

P.00E-2

). Then go to Step 3.

Q: Are the harness wires between SRS-ECU connector

E-07 (terminal No.34 and 36) and side impact sensor
(LH) connector F-13 (terminal No.1 and 2) in good
condition?
YES : Erase the diagnostic trouble code memory, and check

the diagnostic trouble code. If DTC 79 or 93 sets,
replace the SRS-ECU (Refer to

P.52B-215

). Then go

to Step 3.

NO : Repair the harness wires between SRS-ECU

connector E-07 and side impact sensor (LH)
connector F-13. Then go to Step 3.

STEP 3. Recheck for diagnostic trouble code.
Q: Is DTC 79 or 93 set?

YES : Return to Step 1.
NO : The procedure is complete. (If no malfunctions are not

found in all steps, an intermittent malfunction is
suspected. Refer to GROUP 00, How to Use
Troubleshooting/Inspection Service Points

− How to

Cope with Intermittent Malfunction

P.00-6

).

ACX01478AJ

CONNECTOR: E-07

E-07 (Y)

34 35 36 37 38 39 40 41 42

25 26 27 28 29 30 31 32 33

21 22

23 24

HARNESS SIDE
CONNECTOR
(REAR VIEW)

AC204128

CONNECTOR: F-13

AD

F-13 (Y)

HARNESS SIDE
CONNECTOR
(FRONT VIEW)

FRONT SEAT

SIDE IMPACT
SENSOR

2

1

AC204603AC

CONNECTOR: E-19

FLOOR
CONSOLE

E-19

2

1

4

3

E-19

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-169

DTC 81: Left Hand Side-Air Bag Module (Squib) System Fault 1 (Short Circuit between Terminals of
the Squib Circuit)

.

CIRCUIT OPERATION

• The SRS-ECU judges how severe a collision is

by detecting signals from the left and right side
impact sensors. If the impact is over a predeter-
mined level, the SRS-ECU outputs an ignition
signal. At this time, if the side-airbag safing
G-sensor is on, the SRS side-airbag will inflate.

• The ignition signal is input to the side-airbag

module to inflate the side-airbag.

.

DTC SET CONDITIONS
This DTC is set if there is abnormal resistance
between the input terminals of the side-airbag mod-
ule (LH) (squib).

.

MICROCOMPUTER

AIR BAG DRIVE CIRCUIT

SRS-ECU

CONNECTOR
LOCK SWITCH

CONNECTOR
LOCK SWITCH

SIDE AIR BAG
MODULE (SQUIB)
(LH)

NOTE

: CONNECTOR
COUPLED: ON
CONNECTOR
UNCOUPLED: OFF

Side-Airbag Module (LH) (Squib) Circuit

ACX01478AI

CONNECTOR: E-07

E-07 (Y)

AC204635 AB

CONNECTOR: F-15

F-15 (R)

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-170

TROUBLESHOOTING HINTS

• Improper engaged connector or defective short

spring*

• Short circuit between the left-side air bag module

(squib) circuit terminals

• Damaged connector(s)

• Malfunction of the SRS-ECU

.

NOTE: *: The squib circuit connectors integrate a
"short" spring (which prevents the air bag from
deploying unintentionally due to static electricity by
shorting the positive wire to the ground wire in the
squib circuit when the connectors are disconnected)
(Refer to

P.52B-3

). Therefore, if connector E-07 or

F-15 damaged or improperly engaged, the short
spring may not be released when the connector is
connected.

.

DIAGNOSIS

Required Special Tools:

• MB991958: Scan Tool (MUT-III Sub Assembly)

• MB991824: Vehicle Communication Interface (V.C.I.)

• MB991827: MUT-III USB Cable

• MB991911: MUT-III Main Harness B (Vehicles without

CAN communication system)

• MB991865: Dummy resister

• MB991866: Resister harness

STEP 1. Check the diagnostic trouble code.

CAUTION

To prevent damage to scan tool MB991958, always turn the
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991958.
(1) Turn the ignition switch to the "ON" position.
(2) Check if the DTC is set.
(3) Turn the ignition switch to the "LOOK (OFF)" position.
Q: Is DTC 34 set?

YES : Go to Step 2.
NO : Go to Step 3.

AC307591 AB

MB991911

DATA LINK

CONNECTOR

MB991824

MB991827