Mitsubishi Lancer Evolution IX. Manual - part 624

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-9

CHECK CHART FOR DIAGNOSIS CODES

M1524003300885

Inspect according to the inspection chart that is 
appropriate for the diagnosis code.

Code No.

Diagnosis item

Reference Page

1A

Front impact sensor (LH) circuit short

P.52B-11

1B

Front impact sensor (LH) circuit open

P.52B-11

1C

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

P.52B-11

1D

Front impact sensor (LH) short-circuited to earth

P.52B-11

2A

Front impact sensor (RH) circuit short

P.52B-11

2B

Front impact sensor (RH) circuit open

P.52B-11

2C

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

P.52B-11

2D

Front impact sensor (RH) short-circuited to earth

P.52B-11

14

Analogue G-sensor malfunction

P.52B-15

15

Safing G-sensor (for frontal collision) short-circuited

P.52B-15

16

Safing G-sensor (for frontal collision) open-circuited

P.52B-15

21*

2

Driver's air bag module (squib) system (short-circuited 
between terminals of the squib circuit)

P.52B-17

22*

2

Driver's air bag module (squib) system (open-circuited in the 
squib circuit)

P.52B-21

24*

2

Passenger's (front) air bag module (squib) system 
(short-circuited between terminals of the squib circuit)

P.52B-24

25*

2

Passenger's (front) air bag module (squib) system 
(open-circuited in the squib circuit)

P.52B-27

26*

2

Driver's seat belt pre-tensioner (squib) system 
(short-circuited between terminals of the squib circuit) 

P.52B-29

27*

2

Driver's seat belt pre-tensioner (squib) system 
(open-circuited in the squib circuit)

P.52B-34

28*

2

Passenger's (front) seat belt pre-tensioner (squib) system 
(short-circuit between terminals of the squib circuit)

P.52B-38

29*

2

Passenger's (front) seat belt pre-tensioner (squib) system 
(open-circuited in the squib circuit)

P.52B-43

31

SRS-ECU capacitor circuit voltage too high

P.52B-15

32

SRS-ECU capacitor circuit voltage too low

P.52B-15

34*

1

SRS-ECU connector lock out of order

P.52B-47

35

Ignition of the air bag completed

P.52B-49

39

Air bag deployed simultaneously

P.52B-49

41*

1

Power supply voltage (IG1 (A) voltage) drops abnormally.

P.52B-50

42*

1

Power supply voltage (IG1 (B) voltage) drops abnormally.

P.52B-55

43*

1

SRS warning lamp circuit 
open-circuited

Lamp does not illuminate

P.52B-60

Lamp does not switch off

P.52B-64

44*

1

SRS warning lamp circuit malfunction

P.52B-67

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-10

NOTE: 

.

1. *

1

: If the vehicle condition returns to normal, the diagnosis code will be automatically erased, and the SRS 

warning lamp will return to normal.

2. *

2

: However, if no diagnosis code resets, the SRS warning lamp will be switched off (The diagnosis code 

will be retained).

3. If the vehicle has a discharged battery, it will store the diagnosis code 41 or 42. When these diagnosis 

codes are read, check the battery.

45

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

P.52B-15

46*

1

Improper installed of SRS-ECU

P.52B-68

51

Driver's air bag squib activating circuit short-circuited

P.52B-15

52

Driver's air bag squib activating circuit open-circuited

P.52B-15

54

Passenger's (front) air bag squib activating circuit 
short-circuited

P.52B-15

55

Passenger's (front) air bag squib activating circuit 
open-circuited

P.52B-15

56

Driver’s seat belt pre-tensioner activating circuit short- 
circuited

P.52B-15

57

Driver’s seat belt pre-tensioner activating circuit open- 
circuited

P.52B-15

58

Passenger’s (front) seat belt pre-tensioner activating circuit 
short- circuited

P.52B-15

59

Passenger’s (front) seat belt pre-tensioner activating circuit 
open- circuited

P.52B-15

61

Driver's air bag module (squib) system (short-circuited to the 
power supply)

P.52B-69

62

Driver's air bag module (squib) system (short-circuited to the 
earth)

P.52B-72

64

Passenger's (front) air bag module (squib) system 
(short-circuited to the power supply)

P.52B-75

65

Passenger's (front) air bag module (squib) system 
(short-circuited to the earth)

P.52B-77

66

Driver's seat belt pre-tensioner (squib) system 
(short-circuited to the power the supply)

P.52B-79

67

Driver's seat belt pre-tensioner (squib) system 
(short-circuited to the earth)

P.52B-83

68

Passenger's (front) seat belt pre-tensioner (squib) system 
(short-circuited to the power supply)

P.52B-87

69

Passenger's (front) seat belt pre-tensioner (squib) system 
(short-circuited to the earth)

P.52B-91

Code No.

Diagnosis item

Reference Page

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-11

DIAGNOSTIC TROUBLE CODE 
PROCEDURES

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

 

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

 

Code No.1C Front impact sensor (LH) short-circuited to power supply 

 

Code No.1D Front impact sensor (LH) short-circuited to earth 

 

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

 

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

 

Code No.2C Front impact sensor (RH) short-circuited to power supply 

 

Code No.2D Front impact sensor (RH) short-circuited to 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. 

MICROCOMPUTER

INTERFACE CIRCUIT

SRS-ECU

FRONT IMPACT
SENSOR (LH)

FRONT IMPACT
SENSOR (RH)

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

NOTE

: LH drive vehicles
: RH drive vehicles

Front Impact Sensor Circuit

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-12

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 CAUSE

• Damaged harness wires and connectors

• Front impact sensor failed

• Malfunction of the SRS-ECU

DIAGNOSIS

Step 1. Check the front impact sensor.
 Refer to 

P.52B-108

.

Q: Is the check result satisfactory?

YES : 

Go to Step 2.

NO : 

Replace the front impact sensor (Refer to 

P.52B-107

).

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