4 beeps & alarm siren battery

My A3 had a siren replaced under (used) warranty at about 3.5 years old for exactly that problem. It's a bastard to get to on the A3. You have to remove the side trim, subwoofer, cd changer and C/L pump.

I don't know if the siren is coded to the ECU- does anyone know.

I looked in the boot and yes the side trim will have to come off and it is also supposed to be behind the woofer I've been told, so I reckon it won't take the few minutes I was led to believe initially. My only concern is whether it is actually the siren or whether the low voltage problem is elsewhere. Atleast if the siren has an error code that would indicate the exact issue. Does anyone know if it does???

I have the same problem in my 2000 A4. A series of beeps just as I start the engine. I have also checked the forums and come to the conclusion that it is the backup battery for the alarm. I decided to ignore it after reading that it was a pain to fix. Interestingly enough it has stopped doing it over the last few days, I don't know if this is a good thing or not. I have scanned the whole car using VAG-COM and nothing was stored so I guess it doesn't log a fault. I am not even sure of the location of the batteries (if this is problem) as I cannot find them listed in the Bentley manual.

Hope this helps.

Richard

Apparently the batteries are sealed in the horn siren so you have to 'break' the case to go in it. If you've scanned the car and nothing came up then my options look like replace the battery backup and if that fails assume that it there is not enough amps in the main battery. (though it's a Bosch silver and is 71Ah). As the car starts alright I am guessing it's the battery back up.

I scan the car regularly and have never seen any faults related to the alarm and have done this several times while getting the beeps.

Its good to know that the batteries are sealed within another unit !!! My 'main' battery is relatively new and is strong so I suspect my fault is the alarm batteries.

Thanks Richard

I'm glad you told me that - I mainly do very short journeys (school run) so my concern was that it might be the main battery had lost it's capacity to hold charge as well as it used to, though the battery is only about 8 months old. I reckon I'll take it to the local Audi specialist and get them to fit the new unit.

It was definitely the siren unit that was replaced on my A3.

I've since 'top up' charged up by main battery. I think this has meant that the alternator has been able to charge up the battery backup and now the beeping has stopped. Either that or the battery backup has lost so much charge it doesn't work - I'm not sure that is the case as everything else seems fine with the alarm. Think I shall wait and see whether the beeping comes back - I don't want to replace something that isn't broken.