Mitsubishi Montero (2004+). Manual - part 1186

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-79

.

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 there is abnormal resistance 
between the input terminals of the passenger's seat 
belt pre-tensioner (squib).

.

TROUBLESHOOTING HITS

• Open circuit in the passenger's seat belt preten-

sioner (squib) circuit

• Improper connector contact

• 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

AC204127

AB

CONNECTOR: F-29

F-29 (R)

CENTER 
PILLAR

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-80

STEP 1. Check the passenger's seat belt pre-tensioner. 
(Using scan tool MB991958, read the diagnostic trouble 
code).
(1) Disconnect the negative battery terminal.
(2) Disconnect the passenger's seat belt pretensioner 

connector F-29.

(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 diagnostic trouble code memory, and then check the 

diagnostic trouble code.

Q: Is DTC 29 set?

YES : Go to Step 2.
NO :  Replace the passenger's seat belt pre-tensioner 

(Refer to 

P.52B-229

). Then go to Step 3. 

AC204127

AD

CONNECTOR: F-29

F-29 (R)

CENTER 
PILLAR

1 2

HARNESS SIDE
CONNECTOR
(REAR VIEW)

AC006042 AZ

MB991866
(RESISTOR HARNESS)

F-29 HARNESS 
CONNECTOR

MB991865 (DUMMY 
RESISTOR: 3 

Ω)

F-29 SEAT BELT 
PRE-TENSIONER
CONNECTOR (PASSNGER'S SIDE)

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-81

STEP 2. Check the harness for open circuit between 
SRS-ECU connector E-07 (terminal No.27 and 28) and the 
passenger's seat belt pretensioner F-29 (terminal No.1 and 
2).

CAUTION

Do not insert a test probe into the terminal from its front 
side directly as the connector contact pressure may be 
weakened.
(1) Disconnect SRS-ECU connector E-07 and passenger's 

seat belt pretensioner connector F-29, and measure at the 
wiring harness.

(2) Check for continuity between the following terminals.

• Between connector E-07 terminal 28 and connector 

F-29 terminal 2

• Between connector E-07 terminal 27 and connector 

F-29 terminal 1

(3)  It should be less than 2 ohms.
Q: Does continuity exist?

YES : Erase the diagnosis trouble code memory, and check 

the diagnostic trouble code. If DTC 29 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 passenger’s seat belt pre-tensioner 
connector F-29. Then go to Step 3.

STEP 3. Recheck for diagnostic trouble code.
Q: Is DTC 29 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)

AC204127

AD

CONNECTOR: F-29

F-29 (R)

CENTER 
PILLAR

1 2

HARNESS SIDE
CONNECTOR
(REAR VIEW)

AC100327

34 35 36 37 38 39 40 41 42

25 26 27 28 29 30 31 32 33

21 22

23 24

1 2

AF

E-07 HARNESS SIDE
CONNECTOR
(REAR VIEW)

F-29 HARNESS SIDE 
CONNECTOR (REAR VIEW)

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-82

DTC 34: Connector Lock System Detects Connector Unlocked

.

DTC SET CONDITIONS
This DTC is set if a poor connection at the SRS-ECU 
is detected. However, if the vehicle condition returns 
to normal, DTC number 34 will be automatically 
erased, and the SRS warning light will go out.

.

TROUBLESHOOTING HINTS

• Damaged connectors

• 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 SRS-ECU connector E-07, E-08.
Q: Are connectors correctly engaged?

YES : Go to Step 2.
NO :  Engage the connectors correctly. Then go to Step 3.

AC309378

34 35 36 37 38 39 40 41 42

25 26 27 28 29 30 31 32 33

21 22

23 24

E-08 
HARNESS SIDE
CONNECTOR
(REAR VIEW)

E-07 
HARNESS SIDE
CONNECTOR
(REAR VIEW)

AB

CONNECTORS: E-07, E-08

E-07 (Y), E-08(Y)