Alarm going off randomly... Help!

[jedwa115]

I've got what seems to be the same problem as a lot of people - the alarm on my S3 goes off randomly and the only way to stop it happening some days is to leave the car unlocked. Have read a few threads and seems that this is prob a problem with lock sensors or batteries in the boot.

My Q's are:

1. Will a diagnostics check tell me anything categorically or will I still be guessing after paying for it to be plugged in?

2. Am I right that there is no way to lock the car without alarming it?

Cheers, Jon

 

[madvw]

All you will be able to tell from scanning fault codes is how the alarm was triggered. This will be useful in identifying which door or boot latch/lock needs replacing.

However, it won't tell you if the siren battery is duff.

 

[god_thats_quick]

If you disable the interior sensors I think it will stop the alarm going off, it's the button on the drivers door pillar.

 

[jedwa115]

If you disable the interior sensors I think it will stop the alarm going off, it's the button on the drivers door pillar.

No good. That's the first thing I tried. Makes no difference.

As I type, it's been about an hour without going off. That's after "properly" shutting (read "slamming"!) all doors and bonnet. Had the same prob a few weeks back and that seemed to stop it then.

Seems I'll need to have the fault codes checked and then I know which door to have a look at.

 

[AndyMac]

Disconnect the battery and lock it manually.
Had this on my old A3 and it was always on cold nights at 3am, so I put it down to the battery backup issue.

 

[SyA3Turbo]

Its the siren thats the problem. I had my alarm going off randomly. Then it got broken into and didnt sound.

Fitting a new unit in the boot has sorted it though!