Mitsubishi Montero (2002-2004). Manual - part 254

SYMPTOM PROCEDURES

TSB Revision

SWS SYMPTOM PROCEDURES

54Bb-63

INSPECTION PROCEDURE B-1: Tone Alarm: Ignition key reminder tone alarm function does not work 
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

."

.

CIRCUIT OPERATION
The ETACS-ECU operates the ignition key reminder 
tone alarm function (sounds the tone alarm intermit-
tently), based on input signals from the following 
switches:

• Ignition switch (IG1): OFF

• Key reminder switch: OFF

• Driver’s door switch: ON

The ETACS-ECU operates the ignition key reminder 
tone alarm function (sounds the tone alarm intermit-
tently) if any of the following conditions are satisfied:

• Ignition switch: LOCK position (key inserted)

• Driver’s door: OPEN

.

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 key reminder switch may be defective

• The front door switches 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

Ignition Key Reminder Tone Alarm Function

SYMPTOM PROCEDURES

TSB Revision

SWS SYMPTOM PROCEDURES

54Bb-64

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 ETACS-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" 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.54Bb-25

."

AC204222AB

16-pin

13-pin

MB991502

MB991862

SYMPTOM PROCEDURES

TSB Revision

SWS SYMPTOM PROCEDURES

54Bb-65

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 inserted)

• Driver’s door: open

• Front passenger's door: closed

Operate scan tool MB991502 according to the procedure below 
to display "KEY RMND. ALM."

1. Select "SYSTEM SELECT."
2. Select "SWS."
3. Select "SWS MONITOR."
4. Select "FUNCTION DIAG."
5. Select "BUZZER."
6. Select "KEY RMND. ALM."

Check that normal conditions are displayed on the items 
described in the table below.
NOTE: The scan tool display changes when the driver's or the 
front passenger's door is opened. If any of the doors is open, 
the system can not be checked correctly.

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

"FRONT DOOR SW" and "BUZZER"?
YES : Replace the ETACS-ECU. The ignition key reminder 

tone alarm function should now work normally.

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 "FRONT 

DOOR SW": Refer to Inspection Procedure O-5 
"ETACS-ECU does not receive any signal from 
the driver's or the front passenger's door switch 

P.54Bc-23

."

• Normal condition is not displayed on the 

"BUZZER": Go to Step 3.

ITEM NO.

ITEM NAME

NORMAL 
CONDITION

ITEM 30

IG SW (IG1)

OFF

ITEM 32

FRONT DOOR SW

ON

ITEM 43

BUZZER

ON

AC204222AB

16-pin

13-pin

MB991502

MB991862

SYMPTOM PROCEDURES

TSB Revision

SWS SYMPTOM PROCEDURES

54Bb-66

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 MB991502 according to the procedure below 
to display "PULSE CHECK."

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

• Check whether scan tool MB991502 sounds or not when 

the ignition key is removed and reinserted.

Q: Does scan tool MB991502 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.54Bc-49

."

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 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

."

.

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

AC204222AB

16-pin

13-pin

MB991502

MB991862

Light Reminder Tone Alarm Function