i had the same problem... again usually on hot days with the sun roof vented.... my passanger side vanity mirror light continuously stayed on.. even when the car was off and key was out of the ignition so i took car of that and i haven't had the alarm problem... don't know if its luck or that was the problem

 

heat related im sure ( internal sensors will detect anything that moves ) even a fly so it could be the sensors are too sensitive or you left the dog and kids in the car ( look for the obvious first )

 

Random alarms are usually caused by faulty latches, trunk latch, hood latch, door latches.
If the latch is malfunctioning when the alarm is active it will tell the central electrics module that the door is open and will trip the alarm. See it all the time. You need to monitor the latches with the VAG COM, can't tell you which data blocks they all are though.

 

and leaving the dog in the car or kids that's how interior sensors workmovement

 

^^^^^That too. [:-]

 

i think that motion sensor is the most useless thing on our cars. i would jsut rip it out and splice the wires together.

 

Yeah, my 98 the alarm goes completely randomly during the night, day, with the doors locked and windows up. I've even seen it start when I was looking at it from my house. Any Ideas?

 

One of your latches are screwed up or the interior monitoring is going haywire. Push the button on the driver's side b pillar tonight and see if the alarm goes off, that will disable the interior monitoring.

 

Are any A4s made without the motion sensor? Because when I checked for the button, one was labeled for the tilt sensor, and the other was blank. By the way, its 2:18 AM right now, and I'm only awake because my car alarm just went off again... what a pain.

 

If you can find someone with a VAG or VAG it yourself it will tell you a list exactly what has set off the alarm.