Mitsubishi Montero (2004+). Manual — part 1179

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-51

DTC 24: Passenger’s (Front) 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 front impact sensors
and the front air bag analog G-sensor. If the
impact is over a predetermined level, the
SRS-ECU outputs an ignition signal. At this time,
if the front air bag safing G-sensor is on, the SRS
air bag will inflate.

• The ignition signal is input to the air bag module

via the clock spring to inflate the air bag.

.

DTC SET CONDITIONS
This DTC is set if there is abnormal resistance
between the input terminals of the passenger's air
bag module (squib). However, if no DTC resets, the
SRS warning light will be switched off (DTC will be
retained).

MICROCOMPUTER

AIR BAG DRIVE CIRCUIT

SRS-ECU

CONNECTOR
LOCK SWITCH

CONNECTOR
LOCK SWITCH

AIR BAG MODULE
(SQUIB)
(PASSENGER'S SIDE)

NOTE

: CONNECTOR
COUPLED: ON
CONNECTOR
UNCOUPLED: OFF

Passenger's (Front) Air Bag Module (Squib) Circuit

AC204125

CONNECTOR: D-11

AC

D-11 (R)

GLOVE BOX
STRIKER

ACX01478 AG

CONNECTOR: E-08

E-08 (Y)

SRS AIR BAG DIAGNOSIS

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SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-52

.

TROUBLESHOOTING HINTS

• Improper engaged connector or defective short

spring*

• Short circuit between the passenger's 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-08 or

D-11 is 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

SRS AIR BAG DIAGNOSIS

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SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-53

STEP 2. Check SRS-ECU connector E-08.
Q: Is the connector correctly engaged?

YES : Go to Step 3.
NO : Engage the connector correctly. Then go to Step 7.

STEP 3. Check SRS-ECU connector C-12 and passenger’s
air bag module connector C-106. (Using scan tool
MB991958, read the diagnostic trouble code).
(1) Disconnect the negative battery terminal.
(2) Disconnect connectors E-08 and D-11, and then reconnect

them.

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

diagnostic trouble code.

Q: Is DTC 24 set?

YES : Go to Step 4.
NO : The procedure is complete. (It is assumed that DTC

24 set as connector E-08 or D-11 was engaged
improperly).

ACX01478AM

CONNECTOR: E-08

E-08 (Y)

HARNESS SIDE
CONNECTOR
(REAR VIEW)

ACX01478AM

CONNECTOR: E-08

E-08 (Y)

HARNESS SIDE
CONNECTOR
(REAR VIEW)

AC204125

CONNECTOR: D-11

AE

D-11 (R)

GLOVE BOX
STRIKER

1 2

HARNESS SIDE
CONNECTOR
(REAR VIEW)

SRS AIR BAG DIAGNOSIS

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SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-54

STEP 4. Check the passenger's air bag module. (Using
scan tool MB991958, read the diagnostic trouble code).
(1) Disconnect the negative battery terminal.
(2) Unclip passenger’s air bag module connector D-11.

(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) Disconnect the passenger's air bag module connector D-11,

and 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 24 set?

YES : Go to Step 5.
NO : Replace the passenger's air bag module (Refer to

P.52B-217

). Then go to Step 7.

AC204125

CONNECTOR: D-11

AE

D-11 (R)

GLOVE BOX
STRIKER

1 2

HARNESS SIDE
CONNECTOR
(REAR VIEW)

AC006042 AV

MB991865 (DUMMY
RESISTOR: 3

Ω)

MB991866
(RESISTOR HARNESS)

D-11 HARNESS
CONNECTOR

D-11 PASSENGER'S AIR BAG
MODULE CONNECTOR