Mitsubishi Montero (2004+). Manual - part 704

SYMPTOM PROCEDURES

TSB Revision

SIMPLIFIED WIRING SYSTEM (SWS)

54B-73

TONE ALARM

GENERAL DESCRIPTION CONCERNING TONE ALARM

M1549021000229

The ECU related to the alarm function types and var-
ious control functions are as follows.

Ignition key reminder tone alarm function
When the driver’s door is opened with the ignition key inserted 
in the ignition key cylinder (ignition switch is in the OFF posi-
tion) the tone alarm sounds intermittently (horning sound) to 
indicate that the ignition key has not been removed.

Light reminder tone alarm function
When the taillight or headlight is ON, if the ignition key is 
removed and the driver's door is opened, a tone alarm will 
sound continuously to warn that the light is illuminated. How-
ever, if the taillight or headlight has been turned off by the 
headlight automatic-shutdown function, the tone alarm will not 
sound.

FUNCTION

CONTROL ECU

Ignition key reminder tone alarm function

ETACS-ECU

Light reminder tone alarm function

ETACS-ECU, column switch

Seat belt tone alarm function

ETACS-ECU

RV meter operating sound function

ETACS-ECU, RV meter

AC005427AB

ON

OFF

ON

 (Key removed)

OFF

 (Key inserted)

ON (Open)

OFF (Closed)

ON (Tone alarm 

sounds)

OFF (Tone alarm 

does not sound)

Ignition switch
(IG1)

Key 
reminder 
switch

Driver's
door
switch

Ignition key 
inserted 
reminder 
tone alarm 
output

AC005428

AB

ON

OFF

ON 

(Key removed)

OFF 

(Key inserted)

ON (Open)

OFF (Closed)

ON (Tone alarn 

sounds)

OFF (Tone alarm 

does not sound)

Tail light or 
headlight

Key 
reminder 
switch

Driver's
door
switch

Light 
reminder 
tone
alarm output

SYMPTOM PROCEDURES

TSB Revision

SIMPLIFIED WIRING SYSTEM (SWS)

54B-74

Seat belt tone alarm function
If any of the following conditions is met with the igni-
tion switch at "ON" or "ST", the ETACS-ECU sounds 
the tone alarm by using the driver's seat belt switch 
signal.

• The ETACS-ECU sounds the tone alarm for six 

seconds if the ignition switch is turned "ON" while 
the seat belt switch is on (the driver's seat belt is 
not fastened).

• The ETACS-ECU sounds the tone alarm 12 

cycles (after 0.5 seconds) if the seat belt switch is 
on (driver's seat belt is not fastened) when sixty 
seconds or more have elapsed since the ignition 
switch is turned "ON". One cycle consists of 
five-second "on" and then three-second "off".

NOTE: The ETACS-ECU stops sounding immedi-
ately when the seat belt witch is off (driver's seat belt 
is fastened) or the ignition switch is turned to the 
"OFF" or "ACC" position while the seat belt tone 
alarm function is working.

RV meter operating sound function
When tone alarm sounding is requested from the RV 
meter, the ETACS-ECU activates the built-in tone 
alarm. The RV meter will "beep" when adjusting the 
brightness level, only with the ignition key in the 
"ACC" position.

AC308767

Seat belt

tone alarm

sounding 

cycle

ON

(Tone alarm

sounds)

OFF

(Tone alarm

dose not 

sound)

T

t1

T: 3 second

t2: 0.52 second

t1: 0.16 second

t1

t1

t2

6 second 

60 second 

1cycle

(approx.8 second) 

12cycle (applox.90 second) 

5 second 

1 second 

ON

OFF

ON

 (UNFASTENED)

OFF

 (FASTENED)

Ignition

switch (IG1)

Seat

belt

switch

Seat

belt

tone

alarm

output

ON

(Tone alarm

sounds)

OFF

(Tone alarm

dose not 

sound)

AB

SYMPTOM PROCEDURES

TSB Revision

SIMPLIFIED WIRING SYSTEM (SWS)

54B-75

General circuit diagram for Ignition key reminder tone alarm function

SYMPTOM PROCEDURES

TSB Revision

SIMPLIFIED WIRING SYSTEM (SWS)

54B-76

General circuit diagram for light reminder tone alarm function