Alarm keeps going off unprovoked

[Red Head]

I have a 2003 A3 TDI Sport. A few days ago the boot sensor was playing up by saying that the boot was open when it was closed, so I simply opened and closed the boot to eradicate the symbol saying that the boot was open.

The error was fine over the past few days and did not reoccur, but last night the alarm sounded at least once every hour throughout the night. I turned the key in the lock twice to deactivate the alarm but it still sounded, and the symbol did not appear to show that the boot was open. As far as I know, there were no creepy-crawlies in the car. It was not overly windy.

Audi are going to charge £98 simply to initially diagnose the problem, I cant afford that after just buying the car, and no-one I know has the correct lead for Vag Com.

So what is making the alarm sound in an unprovoked manner, every hour throughout the night? It hasn't gone off since 9am htis morning, a knockternal torture of a car alarm, and it sounds crap too!

 

[consilio]

Maybe disconnect the battery for 30mins to clear out any nasty electrical/computer faults?

 

[Gti Jazz Blue]

Sorry but you are going to need a scan to see what is setting the alarm off.

Given that you have had the boot open issue, it could well be a problem with the boot lock. Now I haven't taken a good look at the lock on an A3 but the mark IV Golf has the switch built into the lock.

There was a lot of problems with water from the rear washer leaking into the lock on the Golf. Not saying that the A3 (8P) is the same but it is possible and given that the car has been falsely reporting an open boot - that would be where I'd start looking.

Have you taken a ganders in the phone book to see if there is a local Audi specialist as they may have the required diagnostic capability (CAN-BUS) but charge a lot less than Audi to diagnose the problem.

Paul

 

[Red Head]

Im getting a Canbus cable off ebay and will see if it works when it arrives in a few days. Water leaking is a possibility as it was a damp and miserable night, will investigate further. Plus the rear wash wipe doesnt work-the tank is filled with water and the rear wiper and motor work but the water doesnt come out onto the rear window...

thanks

 

[steveg9]

On my (first) VW Touran it was the comfort sensor (? correct term) that caused random alarm 'events'

 

[Red Head]

Comfort sensor? As in the internal sensor?

 

[Red Head]

Given that you have had the boot open issue, it could well be a problem with the boot lock. Now I haven't taken a good look at the lock on an A3 but the mark IV Golf has the switch built into the lock.

There was a lot of problems with water from the rear washer leaking into the lock on the Golf. Not saying that the A3 (8P) is the same but it is possible and given that the car has been falsely reporting an open boot - that would be where I'd start looking.

Paul

Just started the car there and by chance, the symbol on the dash display says that the boot is open when it is clearly not, gonna tighten the rear lights and have a hoke about to see where the water is coming from, plus look at the rear wash to see where it leads to

 

[Gti Jazz Blue]

Well if you can hear the pump run when you try and wash the rear screen that may well be what is causing your issue.

If it is and you are lucky you may get away with sorting the leak and drying the lock mechanism out.

Paul

 

[Red Head]

Thats it, its where the water is actually being pumped to...

I stuck my fingers down to the catch for the boot lock and it was quite damp, will get a chance to look at it later and fingers crossed that's what the problem is, will be glad to find out

 

[Davidb67]

I had this happen on my `54 2.0 TDi Sport - DIS panel showing boot open, then a few days later the alarm started going nuts.
Luckily my car was still under warranty (not now), and Audi's solution to fix it was to replace the whole boot-catch mech - about £200's worth (although warrantied) if i recall.....

Kinda making up for it now though, £4500 spent in 8 weeks on the piggin thing.....

 

[Red Head]

£4500 spent in 8 weeks? That's a helluva lot of money!

Interestingly, the source of the problem was that the rear wash wipe didnt work when i bought the car. The interior panel was removed in the boot lid and to cut a long story short, after hoking about with the rear wiper mechanism, the water jets were completely blocked on the rear wiper, but the motor was still pumping water to the wiper. This water obviously couldnt escape from the blocked jets so it therefore had nowhere to go and hence exited through near the wiper motor under the interior trim panel in the boot lid.

So with this water exiting at the wrong place, the water travelled a short distance down to the sensor attached beneath the plastic trim panel, then transferred to the catch from the sensor, hence causing the sensor to show that the boot was open on the dash display when it was actually firmly closed and setting the alarm off! Just beacuse of the misdirected water!

Easily sorted, all because the damn washer jets were blocked!

 

[Gti Jazz Blue]

Right I shall keep an eye on that then. Glad you resolved your issue.

Paul

 

[Red Head]

Right I shall keep an eye on that then. Glad you resolved your issue.

Paul

You were right about the mark IV golf, that inspired me to check the boot lock area, spot on thanks!

The alarm hasn't gone off since in the A3, problem solved and boot is dry!

Something to look out for on the 8P's!

Jen

 

[Amchlolor]

There was a lot of problems with water from the rear washer leaking into the lock on the Golf.

Yup, my MKIV Gti had that, so the alarm went off willy-nilly.