Mitsubishi Montero (2002-2004). Manual — part 345

SYMPTOM PROCEDURES

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SWS SYMPTOM PROCEDURES

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INSPECTION PROCEDURE L-1: Fog Light: Fog lights do not illuminate when the fog light switch is
operated.

NOTE: This troubleshooting procedure requires the
use of scan tool MB991502 and SWS monitor kit
MB991862. For details on how to use the SWS mon-
itor, refer to "How to use SWS monitor

P.54Ba-8

."

Fog Light Circuit

SYMPTOM PROCEDURES

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SWS SYMPTOM PROCEDURES

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.

CIRCUIT OPERATION

• The ETACS-ECU sends a fog light illumination

request signal ("LIGHT ON" signal) to the front-
ECU when the fog light switch is turned on while
the headlights are on.

• Then the front-ECU switches on its relay to illumi-

nate the fog lights.

.

TECHNICAL DESCRIPTION (COMMENT)
If the headlights illuminate normally, the fog light
relay, the fog light switch, the front-ECU or the
ETACS-ECU may be defective.

.

TROUBLESHOOTING HINTS

• The fog light relay may be defective

• The fog light switch may be defective

• The front-ECU may be defective

• The ETACS-ECU may be defective

• The wiring harness or connectors may have

loose, corroded, or damaged terminals, or termi-
nals pushed back in the connector

DIAGNOSIS

Required Special Tools:

• MB991223: Harness Set

• MB991502: Scan Tool (MUT-II)

• MB991862: SWS monitor kit

STEP 1. Verify the headlight operation.
Q: Do the headlights illuminate normally?

The lights illuminate normally at both high and low
beams : Go to Step 2.
Headlights do not Illuminate at low beam : Refer to

Inspection Procedure J-2 "Headlights (low-beam) do
not illuminate normally

P.54Bb-308

."

Headlights do not Illuminate at high beam : Refer to

Inspection Procedure J-3 "Headlights (high-beam) do
not illuminate normally

P.54Bb-313

."

AC204183

CONNECTORS : A-07X, A-13X

A-13X

A-07X

AJ

AC204167

CONNECTORS : A-15, A-21, A-25

A-15

AQ

A-25(B)

A-21(B)

SYMPTOM PROCEDURES

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SWS SYMPTOM PROCEDURES

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STEP 2. Check the input signal by using "FUNCTION
DIAG." menu of the SWS monitor.
Set each switch to the following condition before checking input
signal from the fog light switch:

• Ignition switch: ON

• Fog light switch: ON

NOTE: Turn the ignition switch to the "ON" position in order to
disable the headlight automatic shutdown function.

CAUTION

To prevent damage to scan tool MB991502, always turn the
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991502.
(1) Connect scan tool MB991502 to the data link connector

(16-pin).

(2) Connect SWS monitor kit MB991862 to the data link

connector (13-pin).

(3) Operate scan tool MB991502 according to the procedure

below to display "F.FOG LIGHT"

1. Select "SYSTEM SELECT."
2. Select "SWS."
3. Select "SWS MONITOR."
4. Select "FUNCTION DIAG."
5. Select "LIGHTING."
6. Select "F.FOG LIGHT."

(4) Check that normal conditions are displayed on the items

described in the table below.

Q: Are normal conditions displayed on the "IG SW(IG1)"

and "F.FOG LIGHT"?
YES : Go to Step 3.
NO :

• Normal condition is not displayed on the "IG

SW(IG1)": Refer to Inspection Procedure O-2
"ETACS-ECU does not receive any signal from
the ignition switch (IG1)

P.54Bc-7

."

• Normal condition is not displayed on the "F.FOG

LIGHT": Refer to Inspection Procedure O-3
"ETACS-ECU does not receive any signal from
the fog light switch

P.54Bc-10

."

ITEM NO.

ITEM NAME

NORMAL
CONDITION

ITEM 30

IG SW(IG1)

ON

ITEM 36

F.FOG LIGHT

ON

AC204222AB

16-pin

13-pin

MB991502

MB991862

SYMPTOM PROCEDURES

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SWS SYMPTOM PROCEDURES

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STEP 3. Check the fog light relay.

Q: Is the fog light relay in good condition?

YES : Go to Step 4.
NO : Replace the fog light relay. Verify that the fog lights

illuminate normally.

STEP 4. Check the battery power supply circuit to the fog
light relay. Test at fog light relay connector A-13X.
(1) Disconnect fog light relay connector A-13X and measure at

the voltage available at the relay box side of the connector.

(2) Measure the voltage between terminal 3 and ground, and

also between terminal 4 and ground.

• The voltage should be approximately 12 volts (battery

positive voltage).

Q: Is the measured voltage approximately 12 volts (battery

positive voltage)?
YES : Go to Step 7.
NO : Go to Step 5.

BATTERY
VOLTAGE

TESTER
CONNECTION

SPECIFIED
CONDITION

Not applied

4

− 5

Open circuit

3

− Battery (+)

terminal,
1

− Battery (-)

terminal

4

− 5

Less than 2 ohms

4

5

3

1

AC204764

1

5

4

3

2

RELAY SIDE

AB

FOG LIGHT RELAY

AC204183

CONNECTOR : A-13X

RELAY BOX SIDE

AF

2 1

5

4

3

A-13X

1

2

3

4

5

ACX01590AB

CONNECTOR A-13X
(RELAY BOX SIDE)