Audi A4 B6 Avant TDI - Random Alarm /Flat Battery

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Thu 26 Nov 2015 09:17
Audi A4 B6 Avant TDI - Random Alarm /Flat Battery - A3 A4

Over the last month or so the alarm my A4 Avant has been going off randomly, even to the point that it sometimes won't switch off. It seemed to cure itself, about a month ago.
This morning the car had all its indicators going and a flat battery (18 months old) I'm guessing the alarm was triggered for whatever reason and as its not that noisey we didn't hear it.

Consequently the indicators keep flashing and flatten the battery. I'm guessing damp/condensation has something to do with it. I don't believe its the rear washers leaking into the lock switch, that has been fixed previously.

Is there anyway that the alarm can be bypassed so that when locking the car the alarm doesn't set, as I'm having to leave the car unlocked at the moment.

Any other ideas where I may trace this fault to, grateful for any help.

Thanks!

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Thu 26 Nov 2015 10:47
Audi A4 B6 Avant TDI - Random Alarm /Flat Battery - RobJP

There will be a method of disabling the alarm.

On BMWs, for example, you press the 'lock' button on the fob twice in rapid succession to lock the car and disable the alarm.

Do you have the handbook available ? Or know someone else with a similarly-age VAG car ? I'd guess they will all follow a similar procedure

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Thu 26 Nov 2015 10:51
Audi A4 B6 Avant TDI - Random Alarm /Flat Battery - dieselnut

Pull up the front passenger carpet & the thick foam underneath.

The comfort control ECU for the alarm & windows etc lives at the bottom of the floor & will probably be swimming in water.

As far as I know there is no way to bypass it, the indicators are wired in direct.

If it's wet there check the plenum chamber where the battery sits, the drainage holes get blocked.

Also replace the pollen filter HOUSING seal with the new solid rubber type.

Edited by dieselnut on 26/11/2015 at 10:58

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Thu 26 Nov 2015 11:45
Audi A4 B6 Avant TDI - Random Alarm /Flat Battery - A3 A4

Thanks for the reply's so far, I did check the plenum chamber when I changed the battery, it was dry, although I will check under the carpets at the weekend.

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Thu 26 Nov 2015 18:18
Audi A4 B6 Avant TDI - Random Alarm /Flat Battery - elekie&a/c doctor

I would disconnect the sounder,these can also give problems with the alarm sytem.If I recall,it is in the boot area ,below the right rear light.

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Mon 30 Nov 2015 12:34
Audi A4 B6 Avant TDI - Random Alarm /Flat Battery - A3 A4

Occured again over the weeked, this time after the battery went flat the remote central lock ceased to operate and connot 'retune it'.

Using the key, it will only unlock the doors, not the tailgate, I checked the ECU under the passenger carpet - bone dry, also checked the rear wiper motor for leaks, again bone dry, nighmare to remove and replace the trim.

Will the alarm sounder cause problems with the central locking?

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Mon 30 Nov 2015 13:22
Audi A4 B6 Avant TDI - Random Alarm /Flat Battery - elekie&a/c doctor

Possibly yes,thats why you need to disconnect the sounder.

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Tue 1 Dec 2015 23:33
Audi A4 B6 Avant TDI - Random Alarm /Flat Battery - A3 A4

Thanks for the advice, after a bit of graft removing the trim to get to the sounder, I removed it and the remote central locking started working again.

It would appear that the sounders fitted to A4s, 3s, 6s and TTs give a myriad of problems, the onboard rechargeables leak onto the circuitboard, as had happened in my case.

A little too early to say as the alarm was so random, hopefully its cured, all be it alarmless.

Edited by A3 A4 on 01/12/2015 at 23:46

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Thu 3 Dec 2015 15:31
Audi A4 B6 Avant TDI - Random Alarm /Flat Battery - A3 A4

Alas! Back again, again this morning, indicators flashing/flat battery, no central locking.

I have now noticed that when the rear o/s door when open does not activate the internal light or show on the dash as being open. Clutching at straws here, but could this be the problem? My thinking though is that if the microswitch is 'open' when the door is shut/locked only when the switch closes the alarm would go off, hence if the switch is permanently open the alarm won't be activated?

It could be that the switch is faulty and randomly closing thus activating the alarm, if so would cutting one of the wires be a problem? Is the switch open or closed to activate the alarm?

Thanks!

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