Mitsubishi Lancer Evolution IX. Manual - part 180

INPUT SIGNAL PROCEDURES

SMART WIRING SYSTEM (SWS) NOT USING SWS MONITOR

54B-283

INSPECTION PROCEDURE L-14: The rear fog lamp switch signal is not received.

CAUTION

Whenever the ECU is replaced, ensure that the 
input signal circuit is normal.

COMMENTS ON TROUBLE SYMPTOM

Input signal from the rear fog lamp switch is used to 
operate the rear fog lamps. If the signal is abnormal, 
the rear fog lamps will not illuminate and extinguish 
normally.

POSSIBLE CAUSES

• Malfunction of the fog lamp switch

• Malfunction of the ETACS-ECU

• Damaged harness wires and connectors

ETACS-
ECU

FOG LAMP
SWITCH

<LHD>

<RHD>

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

Rear Fog Lamp Switch Input Circuit

INPUT SIGNAL PROCEDURES

SMART WIRING SYSTEM (SWS) NOT USING SWS MONITOR

54B-284

DIAGNOSTIC PROCEDURE

Step 1. Connector check: C-20 fog lamp switch 
connector

Q: Is the check result normal?

YES : 

Go to Step 2.

NO : 

Repair the defective connector.

Step 2. Check the rear fog lamp switch.
Refer to GROUP 54A 

− Rear fog lamp 

P.54A-64

.

Q: Is the check result normal?

YES : 

Go to Step 3.

NO : 

Replace the fog lamp switch.

Step 3. Resistance measurement at the C-20 fog 
lamp switch connector

(1) Remove the fog lamp switch, and measure at the 

wiring harness side.

(2) Continuity between C-20 fog lamp switch 

connector terminal No.6 and body earth

OK: 2

Ω or less

Q: Is the check result normal?

YES : 

Go to Step 5.

NO : 

Go to Step 4.

AC310446

Harness side

AH

Connector: C-20
<LHD>

AC310456

Harness side

AI

Connector: C-20
<RHD>

AC310446

Harness side

AH

Connector: C-20
<LHD>

AC310456

Harness side

AI

Connector: C-20
<RHD>

AC301541HA

Connector C-20
(Harness side)

INPUT SIGNAL PROCEDURES

SMART WIRING SYSTEM (SWS) NOT USING SWS MONITOR

54B-285

Step 4. Check the wiring harness between C-20 
fog lamp switch connector terminal No.6 and 
body earth.

NOTE: 

Prior to the wiring harness inspection, check joint 
connector C-101 <LH driver vehicles> or C-06 <RH 
drive vehicles>, and repair if necessary.

• Check the earth wires for open circuit.

Q: Is the check result normal?

YES : 

The trouble can be an intermittent 

malfunction (Refer to GROUP 00 

− How to 

Cope with Intermittent Malfunction 

P.00-5

).

NO : 

Repair the wiring harness.

Step 5. Connector check: C-227 ETACS-ECU 
connector

Q: Is the check result normal?

YES : 

Go to Step 6.

NO : 

Repair the defective connector.

AC310446

Harness side

AH

Connector: C-20
<LHD>

AC310456

Harness side

AI

Connector: C-20
<RHD>

AC310446

Connector: C-101
<LHD>

AF

Harness side

AC310456

Connector: C-06
<RHD>

AG

Harness side

AC310450

Connector: C-227

AG

Junction block 
(rear view)

Harness side

<LHD>

28

37

43

29

44

38

23

32

41

24

25

26

27

34

42

36 35

33

21

22

30

39

40

31

AC310461

Harness side

Junction block (rear view)

Connector: C-227

AF

<RHD>

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

41

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43

44

INPUT SIGNAL PROCEDURES

SMART WIRING SYSTEM (SWS) NOT USING SWS MONITOR

54B-286

Step 6. Check the wiring harness between C-227 
ETACS-ECU connector terminal No.21 and C-20 
fog lamp switch connector terminal No.5.

• Check the input line for open circuit.

Q: Is the check result normal?

YES : 

Go to Step 7.

NO : 

Repair the wiring harness.

Step 7. Retest the system.
Check that the rear fog lamp switch signal is 
received normally.

Q: Is the check result normal?

YES : 

The trouble can be an intermittent 

malfunction (Refer to GROUP 00 

− How to 

Cope with Intermittent Malfunction 

P.00-5

).

NO : 

Replace the ETACS-ECU.

AC310446

Harness side

AH

Connector: C-20
<LHD>

AC310456

Harness side

AI

Connector: C-20
<RHD>

AC310450

Connector: C-227

AG

Junction block 
(rear view)

Harness side

<LHD>

28

37

43

29

44

38

23

32

41

24

25

26

27

34

42

36 35

33

21

22

30

39

40

31

AC310461

Harness side

Junction block (rear view)

Connector: C-227

AF

<RHD>

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

41

42

43

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