Mitsubishi Montero (2004+). Manual — part 1206

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-159

TROUBLESHOOTING HINTS

• Damaged wiring harnesses or connectors

• Short to the power supply in the side-airbag mod-

ule (RH) (squib) harness

• Malfunction of the SRS-ECU

.

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 side-airbag module (RH). (Using scan
tool MB991958, read the diagnostic trouble code).
(1) Disconnect the negative battery terminal.
(2) Disconnect the side-airbag module (RH) connector F-21.

(3) Connect special tool MB991865 to special tool 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 connector by

backprobing.

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

diagnostic trouble code.

Q: Is DTC 75 set?

YES : Go to Step 2.
NO : Replace the seat back assembly of the front seat

(RH) (Refer to GROUP 52A, Front Seat

P.52A-14

).

Then go to Step 4.

ACX01649

X0942CA

AF

CONNECTOR: F-21

F-21 (R)

1 2

HARNESS SIDE
CONNECTOR
(REAR VIEW)

AC006042 AW

MB991866
(RESISTOR HARNESS)

F-21 HARNESS
CONNECTOR

F-21 SIDE-AIRBAG
MODULE (RH) CONNECTOR

MB991865 (DUMMY
RESISTOR: 3

Ω)

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-160

STEP 2. Check the side-airbag module (RH) circuit at the
SRS-ECU connector E-07.
(1) Disconnect SRS-ECU connector E-07.

DANGER

To prevents the air bag from deploying unintention-
ally, disconnect the side-airbag module (RH) connec-
tor F-21 to short the squib circuit.

(2) Disconnect side-airbag module connector F-21.
(3) Turn the ignition switch to the "ON" position.

CAUTION

Do not insert a test probe into the terminal from its front
side directly as the connector contact pressure may be
weakened.
(4) Measure the voltage between E-07 harness connector

terminals 23, 24 and baby ground.
Voltage should measure 0 volt.

Q: Is the measured voltage within the specified range?

YES : Erase the diagnostic trouble code memory, and check

the diagnostic trouble code. If DTC 75 sets, replace
the SRS-ECU (Refer to

P.52B-215

). Then go to Step

4.

NO : Go to Step 3.

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)

ACX01649

X0942CA

AF

CONNECTOR: F-21

F-21 (R)

1 2

HARNESS SIDE
CONNECTOR
(REAR VIEW)

34 35 36 37 38 39 40 41 42

25 26 27 28 29 30 31 32 33

21 22

23 24

AC203788AI

E-07 HARNESS SIDE
CONNECTOR (REAR VIEW)

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-161

STEP 3. Check the harness wires for short circuit to power
supply between SRS-ECU connector E-07 (terminal No.23
and 24) and side-airbag module (RH) connector F-21
(terminal No.1 and 2).
Q: Are the harness wires between SRS-ECU connector

E-07 (terminal No.23 and 24) and side-airbag module
(RH) connector F-21 (terminal No.1 and 2) in good
condition?
YES : Go to Step 4.
NO : Repair the harness wires between SRS-ECU

connector E-07 and side-airbag module (RH)
connector F-21. Then go to Step 4.

STEP 4. Recheck for diagnostic trouble code.
Q: Is DTC 75 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)

ACX01649

X0942CA

AF

CONNECTOR: F-21

F-21 (R)

1 2

HARNESS SIDE
CONNECTOR
(REAR VIEW)

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-162

DTC 76: Right Hand Side-Airbag Module (Squib) System Fault Ground Circuit (Short-Circuited to
Ground)

.

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 aside-airbag.

.

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

.

MICROCOMPUTER

AIR BAG DRIVE CIRCUIT

SRS-ECU

CONNECTOR
LOCK SWITCH

CONNECTOR
LOCK SWITCH

SIDE AIR BAG
MODULE (SQUIB)
(RH)

NOTE

: CONNECTOR
COUPLED: ON
CONNECTOR
UNCOUPLED: OFF

Side-Airbag Module (RH) (Squib) Circuit

ACX01478AI

CONNECTOR: E-07

E-07 (Y)

ACX01649

X0942CA

AD

CONNECTOR: F-21

F-21 (R)