Mitsubishi Montero (2004+). Manual - part 793

SYMPTOM PROCEDURES

TSB Revision

SIMPLIFIED WIRING SYSTEM (SWS)

54B-429

RELAY 
BOX

JUNCTION
BLOCK

ETACS-
ECU

JUNCTION
BLOCK

FUSIBLE
LINK

1

REAR
PERSONAL
LIGHT

(LH)

(RH)

CARGO
SPACE
LIGHT

DOME LIGHT

MAP
LIGHT

MAP
LIGHT

DOME
LIGHT

Interior Light Circuit

SYMPTOM PROCEDURES

TSB Revision

SIMPLIFIED WIRING SYSTEM (SWS)

54B-430

.

CIRCUIT OPERATION
The ETACS-ECU illuminates the front dome light, the 
cargo space light and the rear personal lights accord-
ing to the following signals:

• Ignition switch (IG1)

• Key reminder switch

• Front door switch (LH)

• All door switches

• Driver’s door lock actuator switch

.

TECHNICAL DESCRIPTION (COMMENT)
If the front dome light and the rear dome light do not 
illuminate normally, the dome light bulb(s) may be 
burned out or the input circuit system from the 
switches, the power supply lines to the switches or 
the ETACS-ECU may be defective (refer to "CIR-
CUIT OPERATION"). Alternatively, the delay-off 
function may be set to "0 second" by using the con-
figuration function.

.

TROUBLESHOOTING HINTS

• The key reminder switch may be defective

• The door switch may be defective

• The driver’s door lock actuator switch may be 

defective

• The dome light may be defective

• The cargo space light may be defective

• The rear personal light 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

ACX02274

FUSIBLE LINK (1)

AE

BATTERY

AC204170

CONNECTORS : D-26, D-28

BP

D-28

D-26

AC204173

CONNECTORS : D-207, D-211

D-207

D-211(B)

AQ

AC204174

CONNECTOR : D-222            

AE

AC204177

CONNECTORS: F-03, F-04

AP

F-03

F-04

AC204178

CONNECTORS : F-06, F-08

AR

F-06

F-08 (GR)

SYMPTOM PROCEDURES

TSB Revision

SIMPLIFIED WIRING SYSTEM (SWS)

54B-431

DIAGNOSIS

Required Special Tools:

• MB991223: Harness Set 

• MB991958: Scan Tool (MUT-III Sub Assembly)

• MB991824: Vehicle Communication Interface (V.C.I.)

• MB991827: MUT-III USB Cable

• MB991911: MUT-III Main Harness B

• MB991813: SWS Monitor Kit

• MB991806: SWS Monitor Cartridge

• MB991812: SWS Monitor Harness (For Column-ECU)

• MB991822: Probe Harness

STEP 1. Verify the adjustment function.
Q: Is the interior light delay-off time set to "7.5 seconds," 

"10 seconds," "15 seconds" or "30 seconds" by using 
the adjustment function?
YES : Go to Step 2.
NO :  Set the interior light delay-off time to "7.5 seconds," 

"10 seconds," "15 seconds" or "30 seconds" by using 
the adjustment function. Verify that the interior light 
illuminates normally.

STEP 2. Use scan tool MB991958 to select "ECU COMM 
CHK" on the SWS monitor display.
Check the ETACS-ECU.

CAUTION

To prevent damage to scan tool MB991958, always turn the 
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991958.
(1) Connect the special tool. Refer to "How to connect SWS 

monitor 

P.54B-7

.

(2) Turn the ignition switch to the "LOCK" (OFF) position.
(3) Operate scan tool MB991958 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."

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

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

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

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

with ETACS-ECU is impossible 

P.54B-42

."

AC309091

MB991911

MB991827

MB991824 

AB

MB991806

MB991862

DATA LINK
CONNECTOR 
(16-PIN)

DATA LINK
CONNECTOR 
(13-PIN)

SYMPTOM PROCEDURES

TSB Revision

SIMPLIFIED WIRING SYSTEM (SWS)

54B-432

STEP 3. Check the input signal by using "DATA LIST" 
menu of the SWS monitor.
Turn the ignition switch to the "OFF" position before checking 
input signals from the ignition switch:
Operate scan tool MB991958 according to the procedure below 
to display "ETACS ECU."

1. Select "SYSTEM SELECT."
2. Select "SWS."
3. Select "SWS MONITOR."
4. Select "DATA LIST."
5. Select "ETACS ECU."

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

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

YES : Go to Step 4.
NO :  Refer to Inspection Procedure O-2 "ETACS-ECU 

does not receive a signal from the ignition switch 
(IG1) 

P.54B-505

."

ITEM NO.

ITEM NAME

NORMAL 
CONDITION

ITEM 30

IG SW (IG1)

OFF

AC309091

MB991911

MB991827

MB991824 

AB

MB991806

MB991862

DATA LINK
CONNECTOR 
(16-PIN)

DATA LINK
CONNECTOR 
(13-PIN)