Mitsubishi Lancer (4A9 engine). Manual - part 130

FOG LAMP

CHASSIS ELECTRICAL

54A-182

SYMPTOM PROCEDURES

Inspection Procedure 1: The front fog lamps do not illuminate normally.

CAUTION

Whenever the ECU is replaced, ensure that the power supply circuit, the earth circuit and the commu-
nication circuit are normal.

FOG LAMP

CHASSIS ELECTRICAL

54A-183

Front Fog Lamp And ETACS-ECU Communication Circuit

FRONT 
FOG LAMP 
RELAY

RELAY BOX

ENGINE 
COMPARTMENT

ETACS-ECU

FUSIBLE 
LINK

38

FUSIBLE 
LINK

36

NOTE

:EXCEPT 1800-DIESEL
:1800-DIESEL

FRONT FOG 
LAMP 

(LH)

(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 : Grey     R : Red     P : Pink     V : Violet     PU : Purple     SI : Silver

FOG LAMP

CHASSIS ELECTRICAL

54A-184

CIRCUIT OPERATION
If the front fog lamps do not illuminate normally, the 
input signal circuit(s) below or the ETACS-ECU may 
be defective.

• Tail lamp switch

• Headlamp switch

• Fog lamp switch

• Option coding information

COMMENTS ON TROUBLE SYMPTOM
When the front fog lamps do not illuminate normally, 
the mentioned input signal circuit(s) or ETACS-ECU 
may be defective.

PROBABLE CAUSES

• Malfunction of column switch

• Malfunction of the ETACS-ECU

• Damaged harness wires and connectors

DIAGNOSIS PROCEDURE

STEP 1. ETACS-ECU coding data check
(1) Operate the M.U.T.-III to read the ETACS-ECU 

option coding information (Refer to GROUP 00 

− 

Coding Table ).

(2) Check that the "Front fog lamp" is set to 

"Present."

Q: Is the check result normal?

YES : 

Go to Step 2.

NO : 

Operate the M.U.T.-III to set the option 
coding "Front fog lamp" to "Present," and 
check the trouble symptom.

STEP 2. Check the operation of the position 
lamps and the headlamps.
Check that the position lamps and the headlamps 
illuminate normally.

Q: Is the check result normal?

YES : 

Go to Step 3.

NO : 

Check the position lamps and the 
headlamps (Refer to trouble symptom chart 
).

STEP 3. M.U.T.-III diagnosis code
Check if diagnosis code is set to the ETACS-ECU.

Q: Is the diagnosis code set?

YES : 

Troubleshoot the ETACS-ECU. Refer to .

NO : 

Go to Step 4.

STEP 4. M.U.T.-III data list
Use the ETACS-ECU service data to check the sig-
nal related to the operation of front fog lamp function.

• Turn the fog lamp switch to ON.

OK: Normal condition is displayed.

Q: Is the check result normal?

AC612144

AC801941

AI

Connector: A-12X

ACA00916

A-49 (B)

Connectors: A-39, A-49

A-39 (B)

AG

ACA00886

AJ

Connector: C-312 <LHD>
ETACS-ECU

ACA00887

AJ

Connector: C-312 <RHD>
ETACS-ECU

Item No.

Item name

Normal 
condition

Item 345

Fog lamp ON

ON

FOG LAMP

CHASSIS ELECTRICAL

54A-185

YES : 

Go to Step 5.

NO : 

Troubleshoot the ETACS-ECU. Refer to 
Inspection Procedure 11 "The column 
switch signal is not received" .

STEP 5. Connector check: A-12X front fog lamp 
relay connector

Q: Is the check result normal?

YES : 

Go to Step 6.

NO : 

Repair the defective connector.

STEP 6. Check the front fog lamp relay
Refer to .

Q: Is the check result normal?

YES : 

Go to Step 7.

NO : 

Replace the front fog lamp relay.

STEP 7. Voltage measurement at the A-12X front 
fog lamp relay connector
(1) Remove the front fog lamp relay, and measure at 

the relay box side.

(2) Measure the voltage between terminal 2 and the 

body earth, and between terminal 4 and body 
earth.

OK: System voltage

Q: Is the check result normal?

YES : 

Go to Step 9.

NO : 

Go to Step 8.

STEP 8. Wiring harness check between the A-12X 
front fog lamp relay connector terminal No. 2/4 
and the fusible link (36) <except 1800-DIESEL> or 
(38) <1800-DIESEL>

• Check the output lines for open circuit.

Q: Is the check result normal?

YES : 

Go to Step 13.

NO : 

Repair the wiring harness.

STEP 9. Connector check: C-312 ETACS-ECU 
connector

Q: Is the check result normal?

YES : 

Go to Step 10.

NO : 

Repair the defective connector.

STEP 10. Wiring harness check between the A-
12X front fog lamp relay connector terminal No. 1 
and the C-312 ETACS-ECU connector terminal 
No. 4

• Check the output lines for open circuit.

Q: Is the check result normal?

YES : 

Go to Step 11.

NO : 

Repair the wiring harness.

STEP 11. Wiring harness check between the A-
12X front fog lamp relay connector terminal No. 3 
and the A-39 front fog lamp (LH) or A-49 front fog 
lamp (RH) connector terminal No. 2
NOTE: Before the wiring harness check, check the 
intermediate connector A-44, and then repair that if 
necessary.

• Check the output lines for open circuit.

Q: Is the check result normal?

YES : 

Go to Step 12.

NO : 

Repair the wiring harness.

STEP 12. Wiring harness check between the A-39 
front fog lamp (LH) or A-49 front fog lamp (RH) 
connector terminal No. 1 and the body earth
NOTE: Before the wiring harness check, check the 
intermediate connector A-44, and then repair that if 
necessary.

• Check the earth lines for open circuit.

Q: Is the check result normal?

YES : 

Go to Step 13.

NO : 

Repair the wiring harness.

STEP 13. Retest the system
Check that the front fog lamps illuminate normally.

Q: Is the check result normal?

YES : 

The trouble can be an intermittent 

malfunction (Refer to GROUP 00 

− How to 

use Troubleshooting/inspection Service 
Points 

− How to Cope with Intermittent 

Malfunction ).

NO : 

Replace the ETACS-ECU.