Mitsubishi Montero (2004+). Manual - part 757

SYMPTOM PROCEDURES

TSB Revision

SIMPLIFIED WIRING SYSTEM (SWS)

54B-285

SYMPTOM PROCEDURES

TSB Revision

SIMPLIFIED WIRING SYSTEM (SWS)

54B-286

INSPECTION PROCEDURE I-1: Seat Belt Warning Light: Seat belt warning light does not illuminate.

NOTE: This troubleshooting procedure requires the 
use of scan tool MB991958 and SWS monitor kit 
MB991862. For details on how to use the SWS mon-
itor, refer to "How to use SWS monitor 

P.54B-10

."

IGNITION
SWITCH (IG1)

JUNCTION 
BLOCK

ETACS-
ECU

· IGNITION SWITCH (IG1)

· DRIVER'S SEAT BELT SWITCH  

INPUT SIGNAL

COMBINATION
METER

Seat Belt Warning Light Circuit

AC204170

CONNECTORS : D-03, D-04

BK

D-03(GR)

D-04(GR)

AC204173

CONNECTORS: D-208, D-210

D-208

D-210

AR

SYMPTOM PROCEDURES

TSB Revision

SIMPLIFIED WIRING SYSTEM (SWS)

54B-287

.

CIRCUIT OPERATION

• The ETACS-ECU operates the seat belt warning 

light according to the following switch signals:

• Ignition switch (IG1)

• Driver's seat belt switch

• If the driver turn the ignition switch to the "ON" 

position without fastening the seat belt, the seat 
belt warning light illuminates.

.

TECHNICAL DESCRIPTION (COMMENT)
If the seat belt warning light does not illuminate, the 
input circuit, the combination meter (seat belt warn-
ing light bulb or printed-circuit board) or the 
ETACS-ECU may be defective.

.

TROUBLESHOOTING HINTS

• The driver's side seat belt switch may be defec-

tive

• The combination meter (seat belt warning light 

bulb or printed-circuit board) 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

• 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

AC204174

CONNECTOR : D-224

D-224(B)

AG

SYMPTOM PROCEDURES

TSB Revision

SIMPLIFIED WIRING SYSTEM (SWS)

54B-288

STEP 1. 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) When the ignition switch is turned to the "ON" 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 2.
NO :  Refer to Inspection Procedure A-3 "Communication 

with ETACS-ECU is not possible 

P.54B-42

."

STEP 2. Check the input signal by using "DATA LIST" 
menu of the SWS monitor.
Turn the ignition switch to the "ON" position before checking 
input signals from the ignition switch (IG1).
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: Is normal condition displayed "IG SW (IG1)"?

YES : Go to Step 3.
NO :  Refer to Inspection Procedure O-2 "ETACS-ECU 

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

P.54B-505

."

AC309091

MB991911

MB991827

MB991824 

AB

MB991806

MB991862

DATA LINK
CONNECTOR 
(16-PIN)

DATA LINK
CONNECTOR 
(13-PIN)

ITEM NO.

ITEM NAME

NORMAL CONDITION

ITEM 30

IG SW (IG1)

ON

AC309091

MB991911

MB991827

MB991824 

AB

MB991806

MB991862

DATA LINK
CONNECTOR 
(16-PIN)

DATA LINK
CONNECTOR 
(13-PIN)