Mitsubishi Montero Sport (2004+). Manual - part 739

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-25

DIAGNOSTIC TROUBLE CODE PROCEDURES

DTC 1A Front impact sensor (LH) circuit short DTC 1B Front impact sensor (LH) circuit open DTC 1C 
Front impact sensor (LH) short-circuited to power supply DTC 1D Front impact sensor (LH) 
short-circuited to ground DTC 2A Front impact sensor (RH) circuit short DTC 2B Front impact sensor 
(RH) circuit open DTC 2C Front impact sensor (RH) short-circuited to power supply DTC 2D Front 
impact sensor (RH) short-circuited to ground

AC202214

Front Inpact Sensor Circuit

AB

AC309461AB

CONNECTOR: A-20

A-20 (Y)

AC003287AC

CONNECTOR: A-32

A-32 (Y)

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-26

.

CIRCUIT OPERATION

• When the left and right front impact sensors 

detect a collision, the switches inside the sensors 
turn ON. 

• 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 sends an ignition signal. At this time, if 
the front air bag safing G-sensor is on, the SRS 
air bag will inflate. 

.

DTC SET CONDITIONS
These DTCs are set if there is abnormal resistance 
between the input terminals of the front impact sen-
sors.
The most likely causes for these codes to be set are 
shown in the table below:

.

TROUBLESHOOTING HINTS

• Damaged harness wires and connectors

• Front impact sensor failed

• Malfunction of the SRS-ECU

AC003286

CONNECTOR: C-17

AB

AC003288

CONNECTOR: C-24

AE

SRS-ECU

C-24 (Y)

DTC

SYMPTOM

1A

• Left front impact sensor or its wiring shorted

1B

• Left front impact sensor or wiring open circuit

1C

• Short to the power supply in the left front impact sensor harness

1D

• Short to body ground in the left front impact sensor harness

2A

• Right front impact sensor or its wiring shorted

2B

• Right front impact sensor or wiring open circuit

2C

• Short to the power supply in the right front impact sensor harness

2D

• Short to body ground in the right front impact sensor harness

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-27

DIAGNOSIS

Required Special Tools:

• MB991222: Probe

•  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

Step 1. Check the front impact sensor.

Refer to 

P.52B-81

.

Q: Is the check result satisfactory?

YES : Go to Step 2.
NO :  Replace the front impact sensor (Refer to 

P.52B-79

).

Step 2. Measure the resistance and voltage at SRS-ECU 
connector C-24.

(1) Disconnect SRS-ECU connector C-24.

AC202743

20

19

18

17

7

15

8

16

6

5

4

12

13 14

3

2

1

9 10 11

CONNECTOR: C-24

C-24 (Y)

C-24 HARNESS CONNECTOR:
HARNESS SIDE 
(REAR VIEW) 

AD

SRS-ECU

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-28

CAUTION

Do not insert a test probe into the terminal from its front 
side directly, as the connector contact pressure may be 
weakened.
(2) Take the measurements below at harness-side connector 

C-24.

• Resistance between terminals 1 and 2, and between 3 

and 4.

NG: 2 ohms or less (short circuit) or 2 megohms or 
more (open circuit) 

• Continuity between terminals 1, 2, 3, 4 and body ground

OK: No continuity

• Voltage between terminals 1, 2, 3, 4 and body ground

OK: 0V

Q: Is the check result satisfactory?

YES : Go to Step 4.
NO :  Go to Step 3.

AC100338

AC103684

1314151617181920

5 6 7 8 9 101112

1 2

3 4

AC103683 AJ

C-24 HARNESS SIDE
CONNECTOR 
(REAR VIEW) 

AC100338 

1314151617181920

5 6 7 8 9 101112

1 2

3 4

AC103684 AJ

C-24 HARNESS SIDE
CONNECTOR 
(REAR VIEW) 

AC103372

4

1

2

3

5

7

6

8

16

15

14

13

12

11

10

9

20

19

18

17

AE

4

1

2

3

5

7

6

8

16

15

14

13

12

11

10

9

20

19

18

17

AC210613