Mitsubishi Montero (2002-2004). Manual — part 314

SYMPTOM PROCEDURES

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SWS SYMPTOM PROCEDURES

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General circuit diagram for the daytime running lights

SYMPTOM PROCEDURES

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INSPECTION PROCEDURE J-1: Headlight and Taillight: Taillights does not illuminate normally.

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

."

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CIRCUIT OPERATION
When the lighting switch is set to "TAIL" position, the
"TAIL" signal is sent through the column-ECU (incor-
porated in the column switch) to the front-ECU. If the
front-ECU receives the "TAIL" signal through the col-
umn-ECU, the front-ECU turns on the taillight relay
(incorporated in the front-ECU), thus causing the tail-
lights to illuminate.

.

TECHNICAL DESCRIPTION (COMMENT)
If the taillights do not illuminate normally, the column
switch or the front-ECU may be defective.

.

TROUBLESHOOTING HINTS

• The column switch (taillight switch) may be defec-

tive

• The front-ECU may be defective

• The wiring harness or connectors may have

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

Taillight Relay Circuit

AC204183

CONNECTOR : A-07X

AG

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DIAGNOSIS

Required Special Tools:

• MB991223: Harness Set

• MB991502: Scan Tool (MUT-II)

• MB991862: SWS monitor kit

STEP 1. Use scan tool MB991502 to select "ECU COMM
CHK" on the SWS monitor display.
Check the following ECUs:

• Column-ECU

• Front-ECU

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) Turn the ignition switch to the "LOCK" (OFF) position.
(4) Operate scan tool MB991502 according to the procedure

below to display "ECU COMM CHK."

1. Select "SYSTEM SELECT."
2. Select "SWS."
3. Select "SWS MONITOR."
4. Select "ECU COMM CHK."

(5) Scan tool MB991502 should show "OK" on the "ECU

COMM CHK" menus for both the "COLUMN ECU" and the
"FRONT ECU" menus.

Q: Is "OK" displayed on both the "COLUMN ECU" and

"FRONT ECU" menus?
"OK" are displayed for all the items : Go to Step 2.
"NG" is displayed on the "COLUMN ECU" menu : Refer

to Inspection Procedure A-2 "Communication with
column switch (column-ECU) is not possible

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16

."

"NG" is displayed on the "FRONT ECU" menu : Refer to

Inspection procedure A-4 "Communication with front-
ECU is not possible

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STEP 2. Check the input signal by using "FUNCTION
DIAG." menu of the SWS monitor.
Check the input signals from the following switches:

• Ignition switch: ON

• Lighting switch: TAIL

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

AC204222AB

16-pin

13-pin

MB991502

MB991862

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Operate scan tool MB991502 according to the procedure below
to display "TAILLIGHT."

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

Check that normal conditions are displayed on the items
described in the table below.

Q: Are normal conditions displayed on the "TAILLIGHT

SW", "H/L AUTO-CUT" and "FRONT ECU ACK"?
YES : Go to Step 3.
NO :

• Normal condition is not displayed on the "TAIL

LIGHT SW": Refer to Inspection Procedure O-6
"ETACS-ECU does not receive any signal from
the taillight switch

P.54Bc-31

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• Normal condition is not displayed on the "H/L

AUTO-CUT": Refer to Inspection Procedure J-9
"The headlight automatic shutdown function does
not work normally

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."

• Normal condition is not displayed on the "FRONT

ECU ACK": Replace the front-ECU. Verify that the
taillights illuminate normally.

ITEM NO.

ITEM NAME

NORMAL
CONDITION

ITEM 01

TAILLIGHT SW

ON

ITEM 35

H/L AUTO-CUT

OFF

ITEM 70

FRONT ECU ACK

NORMAL ACK

AC204222AB

16-pin

13-pin

MB991502

MB991862