Mitsubishi Montero (2004+). Manual - part 706

SYMPTOM PROCEDURES

TSB Revision

SIMPLIFIED WIRING SYSTEM (SWS)

54B-81

STEP 3. Check the input signal (by using the pulse check 
mode of the monitor.)

Check the input signals from the key reminder switch.
Operate scan tool MB991958 according to the procedure below 
to display "PULSE CHECK."

1. Select "SYSTEM SELECT."
2. Select "SWS."
3. Select "PULSE CHECK."

• Check whether scan tool MB991958 sounds or not when 

the ignition key is removed and reinserted.

Q: Does scan tool MB991958 sound when the ignition key 

is removed and reinserted?
YES : Replace the ETACS-ECU. The ignition key reminder 

tone alarm function should now work normally.

NO :  Refer to Inspection Procedure P-1 "ETACS-ECU does 

not receive any signal from the key reminder switch 

P.54B-545

."

INSPECTION PROCEDURE B-2: Tone Alarm: Light reminder tone alarm function does not work 
normally.

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

."

.

AC309091

MB991911

MB991827

MB991824 

AB

MB991806

MB991862

DATA LINK
CONNECTOR 
(16-PIN)

DATA LINK
CONNECTOR 
(13-PIN)

Light Reminder Tone Alarm Function

SYMPTOM PROCEDURES

TSB Revision

SIMPLIFIED WIRING SYSTEM (SWS)

54B-82

CIRCUIT OPERATION
 The ETACS-ECU operates the light reminder tone 
alarm function intermittently according to the follow-
ing signals:

• Ignition switch (IG1): OFF

• Front door switch (LH): ON

• Taillight switch: ON

• Headlight switch: ON

 The ETACS-ECU operates the light reminder tone 
alarm function intermittently under the following con-
ditions.

• Ignition switch: LOCK position (key removed)

• Driver’s door: OPEN

• Lighting Switch: Tail or Head position

.

TECHNICAL DESCRIPTION (COMMENT)
If the function does not work normally, the input cir-
cuit system from the switches or the ETACS-ECU 
may be defective (refer to "CIRCUIT OPERATION").

.

TROUBLESHOOTING HINTS

• The front door switches may be defective

• The column switch (turn-signal light and lighting 

switch) 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

SYMPTOM PROCEDURES

TSB Revision

SIMPLIFIED WIRING SYSTEM (SWS)

54B-83

STEP 1. Use scan tool MB991958 to select "ECU COMM 
CHK" on the SWS monitor display.
Check the following ECUs:

• ETACS-ECU

• Column-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) 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 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."

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

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

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

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

Inspection Procedure A-3 "Communication with 
ETACS-ECU is not possible 

P.54B-42

."

"NG" is displayed on the "COLUMN ECU" menu : Refer 

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

P.54B-35

."

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-84

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: OFF (key removed)

• Lighting switch: TAIL or HEAD

• Driver’s door: open

• Front passenger's door: closed

Operate scan tool MB991958 according to the procedure below 
to display "LGT MONI. ALRM."

1. Select "SYSTEM SELECT."
2. Select "SWS."
3. Select "SWS MONITOR."
4. Select "FUNCTION DIAG."
5. Select "BUZZER."
6. Select "LGT MONI. ALRM."

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

Q: Are normal conditions displayed for "HEADLIGHT SW", 

"TAILLIGHT SW", "IG SW IG1", "FRONT DOOR SW", 
"H/L AUTO-CUT" and "BUZZER"?
Normal conditions are displayed for all the items : 

Replace the ETACS-ECU. The light reminder tone 
alarm function should now work normally.

The scan tool does not show the respective normal 
condition for item "HEADLIGHT SW" : Refer to 

Inspection Procedure O-6 "ETACS-ECU does not 
receive any signal from the headlight switch 

P.54B-527

."

The scan tool does not show the respective normal 
condition for item "TAILLIGHT SW" : Refer to Inspection 

Procedure O-6 "ETACS-ECU does not receive any 
signal from the taillight switch 

P.54B-527

."

The scan tool does not show the respective normal 
condition for item "IG SW (IG1)" : Refer to Inspection 

Procedure O-2 "ETACS-ECU does not receive any 
signal from the ignition switch (IG1) 

P.54B-505

."

ITEM NO.

ITEM NAME

NORMAL 
CONDITION

ITEM 00

HEADLIGHT SW

Either of items 
is ON

ITEM 01

TAILLIGHT SW

ITEM 30

IG SW (IG1)

OFF

ITEM 32

FRONT DOOR SW 

ON

ITEM 35

H/L AUTO-CUT

OFF

ITEM 43

BUZZER

ON

AC309091

MB991911

MB991827

MB991824 

AB

MB991806

MB991862

DATA LINK
CONNECTOR 
(16-PIN)

DATA LINK
CONNECTOR 
(13-PIN)