Mitsubishi Colt Ralliart. Manual - part 544

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-14

DIAGNOSTIC TROUBLE CODE 
PROCEDURES

Code No.1A Front impact sensor LH system (short circuit in the sensor)

 

Code No.1B Front impact sensor LH system (open circuit in the sensor)

 

Code No.1C Front impact sensor LH system (short circuited in the power supply)

 

Code No.1D Front impact sensor LH system (short circuited in the earth)

 

Code No.2A Front impact sensor RH system (short circuit in the sensor)

 

Code No.2B Front impact sensor RH system (open circuit in the sensor)

 

Code No.2C Front impact sensor RH system (short circuited in the power supply)

 

Code No.2D Front impact sensor RH system (short circuited in the earth)

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 analogue 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. 

AC510220

SRS-ECU

FRONT IMPACT
SENSOR (RH)

FRONT IMPACT
SENSOR (LH)

Wire colour code
B : Black     LG : Light green     G : Green     L : Blue     W : White     Y : Yellow     SB : Sky blue
BR : Brown     O : Orange     GR : Grey     R : Red     P : Pink     V : Violet

Front Impact Sensor Circuit

AB

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TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-15

DIAGNOSIS CODE SET CONDITIONS

These diagnosis codes are set if these are abnormal 
resistance between the input terminals of the front 
impact sensors.
The most likely causes for these codes to be set are 
shown in the table below:

PROBABLE CAUSES

• Damaged harness wires and connectors

• Front impact sensor failed

• Malfunction of the SRS-ECU

DIAGNOSIS PROCEDURE

STEP 1. Check the front impact sensor.
 Refer to 

P.52B-142

.

Q: Is the check result normal?

YES : 

Go to Step 2.

NO : 

Replace the front impact sensor (Refer to 

P.52B-141

).

STEP 2. Resistance measurement at the 
SRS-ECU connector B-35.
(1) Disconnect the negative battery terminal.

(2) Disconnect SRS-ECU connector B-35.

CAUTION

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

connector B-35.

Code No.

Trouble causes

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 earth 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 earth in the right front impact sensor harness

AC206285

AF

B-35 (Y)

Connector: B-35

Harness side 
connector 
(rear view)
 

AC100338

AC103684

1314151617181920

5 6 7 8 9 101112

1 2

3 4

AC103683 AN

B-35 Harness side 
(rear view)
 

AC100338 

1314151617181920

5 6 7 8 9 101112

1 2

3 4

AC103684 AM

B-35 Harness side 
(rear view)
 

Main

Index

Group

TOC

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-16

• Resistance between terminals 1 and 2 as well 

as 3 and 4.

NG: 2 

Ω or less (short circuit) or 2 MΩ or 

more (open circuit))

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

body earth

OK: Open circuit

Q: Is the check result normal?

YES : 

Go to Step 3.

NO : 

Go to Step 4.

STEP 3. Voltage measurement at the SRS-ECU 
connector B-35.
(1) Disconnect the negative battery terminal.

(2) Disconnect SRS-ECU connector B-35.
(3) Connect the negative battery terminal.
(4) 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.
(5) Take the measurements below at harness-side 

connector B-35.

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

earth

OK: 0V

Q: Is the check result normal?

YES : 

Go to Step 5.

NO : 

Go to Step 4.

AC103372

4

1 2

3

5

7

6

8

16

15

14

13

12

11

10

9

20

19

18

17

AK

B-35 Harness side 
(rear view)
 

AC206285

AF

B-35 (Y)

Connector: B-35

Harness side 
connector 
(rear view)
 

4

1 2

3

5

7

6

8

16

15

14

13

12

11

10

9

20

19

18

17

AC210613

B-35 Harness side 
(rear view)
 

AD

Main

Index

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TOC

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-17

STEP 4. Check the wiring harness between the 
front impact sensor (RH) connector A-24 
(terminals 1 and 2) and SRS-ECU connector B-35 
(terminals 1 and 2) as well as between front 
impact sensor (LH) connector A-13 (terminals 1 
and 2) and SRS-ECU connector B-35 (terminals 4 
and 3).

NOTE: 

Prior to the wiring harness inspection, check interme-
diate connectors B-40, and repair if necessary.

• Check the front impact sensor output line for 

open or short circuit.

Q: Is the check result normal?

YES : 

Go to Step 5.

NO : 

Repair the wiring harness.

STEP 5. Check whether the diagnosis code is 
reset.
Check again if the diagnosis code is set.

Q: Is diagnosis code 1A, 1B, 1C, 1D, 2A, 2B, 2C or 2D 

set?
YES : 

Replace the SRS-ECU (Refer to 

P.52B-143

).

NO : 

An intermittent malfunction is suspected 
(Refer to GROUP 00, How to Cope with 
Intermittent Malfunction 

P.00-13

).

AC313811

Connector: A-13 

A-13 (Y)

AK

Harness side 
(front view)

2

1

AC313797

Connector: A-24

AG

A-24 (Y)

Harness side 
(front view)

2

1

AC206285

AF

B-35 (Y)

Connector: B-35

Harness side 
connector 
(rear view)
 

AC313820 AM

Connector: B-40 

2

6

1

5

9

3

7 8

4

10

Main

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