Mitsubishi Lancer Evolution IX. Manual — part 638

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-65

OPERATION

• Power for the SRS warning lamp is supplied from

the ignition switch (IG1) circuit.

• The SRS warning lamp illuminates when the igni-

tion switch is turned to the "ON" position and
goes out after approximately 7 seconds if there is
not a malfunction in the SRS system.

DIAGNOSIS CODE SET CONDITIONS

• This diagnosis code is set when a short to earth

occurs in the harness between the SRS warning
lamp and SRS-ECU while SRS-ECU is monitor-
ing the lamp and the lamp is ON. However, if the
vehicle condition returns to normal, diagnosis
code 43 will be automatically erased, and the
SRS warning lamp will go out.

TROUBLESHOOTING HINTS

• Damaged wiring harnesses of connectors

• Malfunction of the SRS-ECU

• Malfunction of the combination meter

DIAGNOSIS PROCEDURE

STEP 1. Check the SRS warning lamp.
(1) Disconnect the negative battery cable.

(2) Disconnect the combination meter connector

C-02.

(3) Connect the negative battery cable.
(4) Turn the ignition switch to the "ON" position.

Q: Does the SRS warning lamp go out?

YES :

Go to Step 2.

NO :

Replace the combination meter (Refer to
GROUP 54A

− Combination Meters

Assembly

P.54A-56

).

AC303798

Connector: C-02
<LHD>

AZ

Harness side

C-02 (L)

31

35

36

37

38

39

40

41

45

46

47

48

49

50

51

34

44

33

43

32

42

AC303814

Connector: C-02
<RHD>

AV

Harness side

31

35

36

37

38

39

40

41

45

46

47

48

49

50

51

34

44

33

43

32

42

C-02 (L)

AC311044

SRS warning lamp

AB

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-66

STEP 2. Check the harness for short circuit to
earth between SRS-ECU connector C-12
(terminal No.8) and combination meter connector
C-02 (terminal No.36).

Q: Is the check result normal?

YES :

Go to Step 3.

NO :

Repair the harness wire between SRS-ECU
connector C-12 (terminal No.8) and
combination meter connector C-02 (terminal
No.36).

STEP 3. Check whether the diagnosis code is
reset.

Q: Is diagnosis code 43 set?

YES :

Replace the SRS-ECU (Refer to

P.52B-109

).

NO :

An intermittent malfunction is suspected
(Refer to GROUP 00

− How to Use

Troubleshooting/Inspection Service Points

P.00-5

).

AC101950AJ

SRS-ECU

Harness side
connector
(rear view)

C-12 (Y)

Connector: C-12

AC303798

Connector: C-02
<LHD>

AZ

Harness side

C-02 (L)

31

35

36

37

38

39

40

41

45

46

47

48

49

50

51

34

44

33

43

32

42

AC303814

Connector: C-02
<RHD>

AV

Harness side

31

35

36

37

38

39

40

41

45

46

47

48

49

50

51

34

44

33

43

32

42

C-02 (L)

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-67

Code No.44: SRS warning lamp circuit malfunction

IGNITION
SWITCH (IG1)

MICROCOMPUTER

COMBINATION
METER

WARNING LAMP
DRIVE CIRCUIT

SRS-ECU

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

SRS Warning Lamp Drive Circuit

CONNECTOR
LOCK SWITCH

NOTE

: CONNECTOR
COUPLED: ON
CONNECTOR
UNCOUPLED: OFF

: LH drive vehicles
: RH drive vehicles

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-68

OPERATION

• Power for the SRS warning lamp is supplied from

the ignition switch (IG1).

• The SRS warning lamp illuminates when the igni-

tion switch is turned to the "ON" position and
goes out after approximately 7 seconds if there is
not a malfunction in the SRS system.

DIAGNOSIS CODE SET CONDITIONS

• This diagnosis code is set under one of the fol-

lowing cases while the SRS-ECU is monitoring
the warning lamp drive circuit:

• When a short circuit occurs in the warning

lamp drive circuit.

• When a malfunction is detected in the output

transistor inside the SRS-ECU.

• However, if the vehicle condition returns to nor-

mal, diagnosis code 44 will be automatically
erased, and the SRS warning lamp will go out.

PROBABLE CAUSES

• Damaged wiring harnesses of connectors

• Malfunction of the SRS-ECU

DIAGNOSIS PROCEDURE

Check the SRS warning lamp drive circuit system.
Refer to

P.52B-60

,

P.52B-64

.

Code No. 46 Improper installation of SRS-ECU

DIAGNOSIS CODE SET CONDITIONS

This diagnosis code is set when an SRS-ECU
designed only for the driver's air bag, is installed on
vehicle, which has both driver's and passenger's
(front) air bags. However, if the system returns to
normal condition, code number 46 will be erased
automatically and the SRS warning lamp will go out.

PROBABLE CAUSES

Incorrect SRS-ECU

DIAGNOSIS PROCEDURE

Replace the SRS-ECU to a proper one for equipment
(Refer to

P.52B-109

).