I've got standard Sigma alarm on my 05 wrx. It keeps going off randomly. Even when there's no one around. It's only just started doing it which is weird.

Any ideas what can cause it?

Edit:

Also had a new battery at Xmas and starts up fine so I can't see it being that.

 

do you have the handbook ? as it will explain how to self diagnose the issue or point you towards what triggered it,
bonnet pins are common.
hth

 

Just says check doors, windows are closed and remove air fresheners (hanging ones) and close air vents.

I'll give it a try and see what happens.

 

seems a popular issue
https://www.scoobynet.com/lighting-a...arm-issue.html

 

Most the time it's the ultrasonic sensors, there rubbish

 

Ive found more problems with bonnet pins if honest

 

B. Diagnosis - Last Trigger Memory:
The following should be used to find the last triggered circuit of the alarm. This is useful for identifying the
source of an alarm sounding.
Arm/disarm with remote key or keypad
Then type *17856
(This is the programming PIN code -The alarm will bleep once)
Then *38
(This is the function code to display the last triggered circuit)
Then #
(This sends the request to the system - The alarm will give either one long bleep or two short
bleeps)
The dashboard LED will then flash to indicate the following:
1 Flash = Ignition
2 Flashes = Door Trigger (or Boot or Bonnet on Add On Models Only)
4 Flashes = Boot Trigger (Remote Models Only)
8 Flashes = Bonnet Trigger (Remote Models Only)
16 Flashes = Ultrasonics

Regards Ian

 

Thanks guys i'll have ago and see what happens.