Damn alarm keeps going off. Any ideas as to the cause?

[SyA3Turbo]

I spent most of the night last night switching the alarm on my T sport quattro off. I was round at the girlfriends and the alarm started going off so i disarmed then rearmed it. A few minutes later and it was going again. Checked the bonnet boot and doors and reset it. A few mins later it was going again.

I decided at this point to just leave it unlocked as i really couldnt be bothered. The good old Audi locked itself on its own lol and the alarm went off a few mins later.

In the end i just disconnected the battery and left it unlocked.

Any ideas whats causing it to set off for no reason. All the doors and sensors seemed okay?

 

[god_thats_quick]

I could be because one of the sensors for one of the doors thinking it's left open, my S3 was doing this when the passenger door switch was on the way out. Do any of the interior lights pulse or flash when your in the car. I found that if I slammed the door shut it would help sort the alarm problem, but in the end I changed the door latch (inc switch).

 

[dickys3]

If you would have unlocked the car, opened the door and then close it the car wouldn't have auto alarmed.

Probably a door sensor. This affects people when the weather gets cold so could be related.

 

[paul_brad]

my alarm kept going off, and it was because the siren housed in the boot near your amp was either faulty, or the battery was running low (not the car battery).

Either way, you have to replace the whole unit. If you have been having the 4 beeps upon ignition sometimes when its cold, it will be this. This sound signifies the battery isnt charged properly in the boot.

 

[SyA3Turbo]

Hm, i put the main battery on charge and the "ready" light came on pretty quick, the alarm active "beeb" sounded when i locked it again too.

I have had the four beebs on the ignition a few times, but not recently.

Is the battery actually in the unit itselt?

Anyway of checking the sensors with vagcom?

 

[paul_brad]

the battery is in the siren unit, in the boot. They supply them made as one unit, so even if the battery is dead, you have to get a new siren! I think it throws up errors if you vagcom.

I think it was something like £60 for the unit, plus labour.

I think the problem is, when its cold, the charge isnt holding very well in the battery in the alarm, so when its drained, it thinks its being disconnected, so the alarm goes off! I had to leave mine unlocked for a couple of nights until it was fixed.

good luck!

 

[SyA3Turbo]

Cheers for the info.

Much apreciated!

 

[darkspin]

[ QUOTE ]
the battery is in the siren unit, in the boot. They supply them made as one unit, so even if the battery is dead, you have to get a new siren! I think it throws up errors if you vagcom.


[/ QUOTE ]

fully agree here as i had the same problem recently and had to change the siren unit and now the alarm doesn't go off at all.

The only issue i had was after going to Audi to get the part, Bosch had changed the design of the siren and so it didnt fit back into its usual place on my pre facelift so I had to accomodate it by tying it down next to the rear light in the boot so it didnt move around whilst driving.