Mitsubishi Galant (2004+). Manual - part 304

SYMPTOM PROCEDURES

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SIMPLIFIED WIRING SYSTEM (SWS)

54B-407

STEP 4. Use scan tool MB991958 to select "ECU COMM 
Check" on the SWS monitor display.

Check the ETACS-ECU.

CAUTION

Connect special tool MB991910 before connecting special 
tool MB991812. Be sure to connect special tool MB991806 
after turning on special tool MB991824.
(1) Connect the SWS monitor. Refer to "How to connect SWS 

monitor 

P.54B-13

."

(2) Turn the ignition switch to the "ON" position.
(3) Operate scan tool MB991958 according to the procedure 

below to display "ECU COMM Check."
a. Select "Interactive Diagnosis."
b. Select "System select."
c. Select "SWS."
d. Select "SWS MONITOR."
e. Select "ECU COMM Check."

(4) Scan tool MB991958 should show "OK" on the "ECU 

COMM Check" menu for the "ETACS ECU" menu.

Q: Is "OK" displayed for the "ETACS ECU" menu?

YES : Go to Step 5.
NO :  Refer to Inspection Procedure A-3 "Communication 

with ETACS-ECU is not possible 

P.54B-79

."

STEP 5. Replace the combination meter.
(1) Replace the combination meter.
(2) Check that the turn-signal light indicator lights illuminate 

normally.

Q: Are the turn-signal indicator lights in good condition?

YES : No action is necessary and testing is complete.
NO :  Replace the ETACS-ECU. Check that the turn-signal 

light indicator lights illuminate normally.

AC305411AB

MB991910

DATA LINK

CONNECTOR

MB991827

MB991824

MB991806

MB991812

AC302210

COLUMN SWITCH 
CONNECTOR

COLUMN SWITCH 
CONNECTOR AT 
HARNESS SIDE 

MB991812

AB

SYMPTOM PROCEDURES

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SIMPLIFIED WIRING SYSTEM (SWS)

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FOG LIGHT

GENERAL DESCRIPTION CONCERNING THE FOG LIGHT

M1549021400089

The following ECUs affect the functions and control 
of the fog lights.

Fog light

The fog lights will illuminate only when the fog light 
switch is operated while the low-beam headlights are 
on.
The fog lights will be switched off when any of the fol-
lowing conditions is met. The fog lights will also be 
switched off automatically by headlight automatic 
shutoff function.

• When the high-beam headlights are switched on, 

the fog lights will be switched off. If the low-beam 
headlights are switched on again, the fog lights 
will illuminate again.

• When the headlight switch is turned off or the tail 

lights and headlights are off, the fog lights will be 
switched off. If the low-beam headlights are 
switched on again, the fog lights will not illumi-
nate again.

Fog light indicator
At the same time that the fog lights are illuminated, the 
ETACS-ECU sends a signal to illuminate the fog light indicator 
via the CAN bus line. The combination meter receives the 
transmitted signal and turns the fog light indicator on and off.

General circuit diagram for the fog lights

FUNCTION

CONTROL ECU

Fog light

ETACS-ECU, front-ECU, column switch

Fog light indicator

ETACS-ECU, column switch

AC306459

ON

OFF

ON

OFF

ON

OFF

ON

OFF

Tail light switch

Headlight switch

Dimmer switch

Fog light switch

ON

OFF

Fog light

AB

SYMPTOM PROCEDURES

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SIMPLIFIED WIRING SYSTEM (SWS)

54B-409

BATTERY

FOG LIGHT
RELAY

RELAY BOX

FOG LIGHT
SWITCH

FOG
LIGHT (LH)

FOG
LIGHT (RH)

RHEOSTAT

COL

UMN-ECU

COLUMN SWITCH

LIGHTING

SWITCH

DATA LINK
CONNECTOR

IGNITION
SWITCH (IG1)

ETACS-
ECU

22

RELAY BOX
(FUSE     )

6

RELAY BOX
(FUSE     )

DIMMER

·P

A

S

SING

SWITCH

(HEAD)

(T

AIL)

(DIMMER)

(P

AS

SING)

IGNITION
SWITCH (IG2)

JUNCTION BLOCK

SYMPTOM PROCEDURES

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SIMPLIFIED WIRING SYSTEM (SWS)

54B-410

IGNITION
SWITCH (IG1)

ETACS-
ECU

COMBINATION
METER

CPU

RHEOSTAT
CIRCUIT

22

RELAY
BOX
(FUSE     )

DATA LINK
CONNECTOR