audi a4 cabriolet alarm issue

[seany]

Hi needs some help i fitted an aftermarket stereo to my audi a4 cabriolet yesterday . Since i installed it my cars alarm keeps randomly going off the stereo was plug & play so no wire cutting . Any advice greatly apprieciate .
Thats Sean

 

[pauldazzle]

I'd try unplugging the new stereo. & see if it still happens.
If it doesn't then the batteries in the alarm siren box have probably leaked on the internal PCB, which causes the alarm to go off randomly.(common problem on Audi's)

 

[seany]

Thanks mate will try disconnecting the stereo see what happens. If it is the alarm pcb is it an easy fix ?
Thanks Sean

 

[pauldazzle]

Easy fix is to disconnect it. New siren box from Audi or used on ebay.

 

[seany]

Ok nive one where is the unit mate?
I have taken the stereo out see what happen's over the next couple of day's. I have contacted xtrons & they have suggested it might be there canbus interface draining battery voltage thus setting the alarm off .

 

[pauldazzle]

Not sure about the Cabby, but It's usually buried down in one of rear inner wings.

 

[vr6gordy]

Open up your roof but just let the metal bit lift up then just remove 2 little clips on the drivers side and the alarm is found in there

 

[seany]

Ok guys its defo the new stereo causing the alarm to go off . The new stereo is an xtrons PF72A4AGTR unit with sat nav etc with a can bus decoder every thing works the can bus interface works on the dash display etc . With the new stereo fitted the car alarm randomly goes can be 2-3 hours or 6-8 hours between the times it goes off . i have left the car with no stereo fitted for a couple of days & the car alarm does not go off !!!! I have reinstalled the OEM stereo & the alarm does not go off !!! refit the PF72A4AGTR stereo & after a few hours the car alarm goes off . Any ideas greatly appreciated .

Thanks Sean

 

[vr6gordy]

Your stereo might be running on the same frequency as the alarm ..messing up the signal?? That's why it could be going off ????

 

[seany]

Ok guys my alarm is now going off with the OEM stereo fitted . How do i check the alarm unit to see if it's causing it . It seemed to take a day or so before it would go off bit now its going off every few mins . How do i stop it ?
I done a double din conversion when i fitted the stereo could i have done something to cause it ?

 

[vr6gordy]

The battery's will be dead in the alarm box .. you might be lucky and do the battery mod to fix it if not and the battery's have leaked then you need a new alarm box

 

[vr6gordy]

When you lock the car look at your led on the door if you get a normal pattern of flashes then your alarm is ok but if it misses a flash then it's your alarm

 

[seany]

Hi guys thanks for all the replys . Had my car plugged into vag com on thursday & all the codes cleared . Fingers crossed the alarm has not gone off since .