Audi A4 Cabriolet - Audi A4 (2005) Alarm Problem

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Sun 31 May 2020 21:23
Audi A4 Cabriolet - Audi A4 (2005) Alarm Problem - Ads75

Hi, The alarm on my Audi A4 has suddenly started sounding for no apparent reason. The key fob won't stop it and it even carries on when I start the engine. If it does stop and I lock the car with the fob the red alarm light on the doors flashes for a second and then stays red before the alarm sounds a few seconds later.

The only way I can seem to stop the alarm is to disconnect the negative terminal on the battery. Yesterday I swapped the battery in the key fob and thought id sorted it. The car locked fine with the red alarm lights on the doors going back to intermittent flashing. Unfortunately it only lasted 26 hours before the alarm was going off again!

A quick internet search has suggested the alarm sounded unit itself. Apparently it contains a back up battery which may have died?

I would appreciate some ideas of what could be wrong and approximate costs for fixing at a garage.

Many thanks!

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Sun 31 May 2020 22:17
Audi A4 Cabriolet - Audi A4 (2005) Alarm Problem - Big John

I recently helped a neighbour with a 2003 Audi Avant that was having the very same issue. It was indeed the battery in the sounder that had failed – the problem was getting to it. On the Avant it was under the subwoofer assembly housed in the side of the boot and I had to take half the trim to bits and remove the subwoofer unit and it was just under this. Not sure where it would be on the cabriolet – follow that sound!

In the case of his car we removed the sounder to investigate but fortunately his car has worked perfectly ever since – obviously without the alarm. To properly repair may be interesting as I don’t think you can buy the battery packs now!

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Sun 31 May 2020 22:23
Audi A4 Cabriolet - Audi A4 (2005) Alarm Problem - elekie&a/c doctor

I'll go with that . Battery failure in the power sounder has failed and may have damaged the pcb. I'm sure its in the boot area. The power hood system is in the right side, so either forward of that or on other side. Most people just disconnect it and remove it from the car.

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