Alarm keeps going off!?

[tara_nta]

A4 1.9 tdi 1999
Since I've had the car (3 weeks) whenever I lock the car wether I do it by the button or by the key the alarm doesn't shut up! It doesn't go off straight away, for example last night I got home at 10pm, locked the car by the button. By midnight it was going off!

I had noticed the wires that go to the squishy bonnet sensor thingy lol (please excuse my fantastic descriptions) had come off, so I put new connectors on the ends of those wires and plugged them back in. Still no difference. I haven't got anything loose or hanging inside the car.

Any ideas guys?

 

[aragorn]

Vagcom scan to find out whats triggering it.

It could be a failing siren.

 

[tara_nta]

My friend has got a diagnosticp machine from snap on, wil that scan it? If not how much is vagcom and where to get it? Thanks very much

 

[aragorn]

No idea if the snapon tool will connect to the appropriate controller.

You can buy a vagcom cable off ebay for a tenner and use the free-ware version of the software to get you started.

 

[tara_nta]

Ah lovely, dont suppose you have a link for a the right one?
Thanks for your help mate

 

[tara_nta]

Right, got hold of a vagcom lead and software. Ive plugged it in and scanned the car and its showing fault - alarm triggered terminal 15.
What and where is terminal 15? Bonnet sensor? Door sensor?

 

[Arrkon]

T15 is the ignition feed IIRC... could have a duff ignition switch. if the alarm is armed and it detects a "key on" event, the alarm will trigger.

 

[aragorn]

You'll really need to clear the codes, and wait for the alarm to trigger again.

That T15 code could be ancient.

 

[tara_nta]

Codes have been cleared, alarm has triggered again and its brought up interior monitoring sensor this time. Apparently according to an Audi specialist there is a sensor in the headlining. Remove interior light to reveal it? That sound right?

 

[aragorn]

Nope, interior monitoring is in the tops of the B pillars, two ultrasonic things each side.

If you press the button on the B pillar when you get out, it should disable the interior monitoring. If that doesnt work its presumably a fault with the interior monitoring control box, rather than the sensors.

 

[tara_nta]

Yep, still goes off if i press the button on the b pillar. Where is the monitering box located?

 

[CraigG]

under the rear seat, right in the middle, red plug iirc.

I guess you could try just completely unplugging that control box and see what happens?

 

[tara_nta]

Craig. . . . . Thankyou, i wil investigate! Fingers crossed i can simply unplug it and leave it at that.

 

[tara_nta]

Thanks for your help fellas. . . . . I unplugged the monitering box and the alarm has kept itself quiet!

 

[jcb]

my money is on the alarm siren battery.
it drops dead around the 10 year mark and fritzes everything

I had all those codes and it was the battery unit causing it

 

[Craig Adams]

I have a 1999 A4 B5 (2.8). My similar issue turned out to be corrosion in the key lock pump module (trunk by the tail light). I took the panel off the bottom and found corrosion on the circuit board (top side of the board). I bushed it off with a wire brush and....so far no more random alarms.

 

[Rallyman]

I had this at the 8/9 year old mark, the Nicad batteries die in the alarm. On the avant, the alarm box is located rear drivers side d pillar new central door locking system.
Main stealer part only, the alarm is sealed and is very difficult to repair and put back into service. About £80 ish!