Mitsubishi Montero Sport (2004+). Manual — part 738

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-21

SRS AIR BAG DIAGNOSIS

INTRODUCTION TO SRS DIAGNOSIS

M1524005000385

The SRS system is controlled by the SRS-ECU. The
SRS-ECU judges how severe a collision is by detect-
ing signals from the left and right front impact sen-
sors and the analog G-sensor. If the impact is over a
predetermined level, the SRS-ECU outputs an igni-
tion signal. At this time, if the safing G-sensor is on,
the SRS air bag will inflate.
The SRS warning light in the combination meter
alerts a malfunction of the SRS system.

If the following symptoms occur even when the vehi-
cle has not collided, there may be a malfunction.

• The SRS warning light does not go off within

approximately 7 seconds after the ignition switch
has been turned "ON."

• The SRS warning light does not illuminate when

the ignition switch is turned "ON."

Refer to the Post-collision Diagnosis when inspecting
and servicing the vehicle that has been in a collision
(Refer to

P.52B-74

TROUBLESHOOTING STRATEGY

M1524003100472

Use these steps to plan your diagnostic strategy. If
you follow them carefully, you will be sure that you
have exhausted most of the possible ways to find a
SRS fault.

1. Gather information about the problem from the

customer.

2. Verify that the condition described by the cus-

tomer exists.

3. Check the vehicle for any Diagnostic Trouble

Code (DTC).

4. If you cannot verify the condition but there are no

DTC's, the malfunction is intermittent. Refer to
GROUP 00, How to use Troubleshooting/Inspec-
tion Service Point

− How to Cope With Intermit-

tent Malfunctions

P.00-7

5. If there is a DTC, record the number of the code,

then erase the code from vehicle memory using
scan tool MB991958.

6. Recreate the DTC set conditions to see if the

same DTC will set again.

• If the same DTC sets again, follow the DTC

Chart and find the fault.

• If you cannot get the same DTC to set again,

the malfunction is intermittent. Refer to
GROUP 00, How to use Troubleshoot-
ing/Inspection Service Point

− How to Cope

With Intermittent Malfunctions

P.00-7

DIAGNOSTIC FUNCTION

M1524013800126

HOW TO CONNECT THE SCAN TOOL (MUT-III)

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

SRS AIR BAG DIAGNOSIS

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SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-22

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. Ensure that the ignition switch is at the "LOCK" (OFF)

position.

2. Start up the personal computer.
3. Connect special tool MB991827 to special tool MB991824

and the personal computer.

4. Connect special tool MB991911 to special tool MB991824.
5. Connect special tool MB991911 to the data link connector.
6. Turn the power switch of special tool MB991824 to the "ON"

position.
NOTE: When special tool MB991824 is energized, special
tool MB991824 indicator light will be illuminated in a green
color.

7. Start the MUT-III system on the personal computer.
NOTE: Disconnecting scan tool MB991958 is the reverse of the
connecting sequence, making sure that the ignition switch is at
the "LOCK" (OFF) position.

HOW TO READ AND ERASE DIAGNOSTIC
TROUBLE CODES

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

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.
NOTE: If the battery voltage is low, diagnostic trouble codes will
not be set. Check the battery if scan tool MB991958 does not
display.
1. Connect scan tool MB991958 to the data link connector.
2. Turn the ignition switch to the "ON" position.
3. Select "Interactive Diagnosis" from the start-up screen.
4. Select "System select."
5. Choose "SRS-AIR BAG" from the "BODY" tab.
6. Select "MITSUBISHI."
7. Select "Diagnostic Trouble Code."
8. If a DTC is set, it is shown.
9. Choose "Erase DTCs" to erase the DTC.

AK303629AB

MB991911

MB991827

MB991824

16-PIN

AC206894

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

SRS AIR BAG DIAGNOSIS

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SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-23

M1524003300595

INSPECTION CHART FOR DTC'S

Inspect according to the inspection chart that is appropriate for the DTC.

DTC

ON-BOARD DIAGNOSTIC ITEM

REFERENCE
PAGE

Front impact sensor (LH) circuit short

P.52B-25

Front impact sensor (LH) circuit open

P.52B-25

Front impact sensor (LH) short-circuited to power supply

P.52B-25

Front impact sensor (LH) short-circuited to ground

P.52B-25

Front impact sensor (RH) circuit short

P.52B-25

Front impact sensor (RH) circuit open

P.52B-25

Front impact sensor (RH) short-circuited to power supply

P.52B-25

Front impact sensor (RH) short-circuited to ground

P.52B-25

Analog G-sensor system in the SRS-ECU

P.52B-31

Safing G-sensor short circuit

P.52B-31

Safing G-sensor open circuit

P.52B-31

21*

Driver's side air bag module (squib) system fault 1

P.52B-32

22*

Driver's side air bag module (squib) system fault 2

P.52B-32

24*

Passenger (front) side air bag module (squib) system fault 1

P.52B-36

25*

Passenger (front) side air bag module (squib) system fault 2

P.52B-36

26*

Driver's side seat belt pre-tensioner (squib) system fault 1

P.52B-40

27*

Driver's side seat belt pre-tensioner (squib) system fault 2

P.52B-40

SRS-ECU capacitor circuit voltage too high

P.52B-31

SRS-ECU capacitor circuit voltage too low

P.52B-31

34*

Connector lock system detects connector unlocked

P.52B-44

SRS-ECU air bag condition monitor detects deployed air bag

P.52B-46

Airbags deployed simultaneously

P.52B-46

41*

power circuit system (fuse No.7 circuit)

P.52B-47

42*

power circuit system (fuse No.8 circuit)

P.52B-47

43*

SRS warning light driver circuit system
fault 1

Light does not illuminate

P.52B-54

Light does not switch off

P.52B-54

44*

SRS warning light driver circuit system fault 2

P.52B-54

SRS-ECU non-volatile memory (EEPROM) and A/D converter system

P.52B-31

46*

Improperly installed SRS-ECU

P.52B-61

Driver's side air bag module (squib ignition driver circuit) system detected short
circuit

P.52B-31

Driver's side air bag module (squib ignition driver circuit) system detected open
circuit

P.52B-31

SRS AIR BAG DIAGNOSIS

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SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-24

NOTE:

1. *1: If the vehicle condition returns to normal, the DTC will be automatically erased, and the SRS warning

light will return to normal.

2. *2: However, if no DTC resets, the SRS warning light will be switched off (The DTC will be retained).
3. If the vehicle has a discharged battery, it will store the DTC's 41 or 42. When these DTC's are read, check

the battery condition.

Passenger (front) side air bag module (squib ignition drive circuit) system
detected short circuit

P.52B-31

Passenger (front) side air bag module (squib ignition drive circuit) system
detected open circuit

P.52B-31

Driver's side seat belt pre-tensioner (squib ignition driver circuit) system
detected short circuit

P.52B-31

Driver's side seat belt pre-tensioner (squib ignition driver circuit) system
detected open circuit

P.52B-31

Driver's side air bag module (squib) system fault for power supply circuit

P.52B-32

Driver's side air bag module (squib) system fault for ground circuit