Faulty alarm on 51 reg A4

[outside 12]

Hi there

i have a 2001 51 reg A4 sport TDI and the alarm keeps going off on its own, i've tried various things but have not had any luck so far, it seems to go off is when it drops below 4 degree's, could the senses get tripped by the temperature ? my local Audi garage have not heard of any alam faults before but can put the car on the diagnostic machine. if anyone has had this problem or has advice it will be greatly appriciated

kind regards

13

[JR001]

If your local Audi garage thinks this then it would appear that perhaps they don't know what they are talking about! My first reaction for a car of this year and showing these symptoms is that your siren and its dedicated battery unit need replacing. Unless, of course, you can be sure that this has already been done.
Your complaint is a very common one on this forum and one that I managed to solve in my own car a couple of months ago. My local AUDI garage ran the diag (free of charge) and found error codes related to what I have said above. I saved £70 by removing old and installing new myself. Other forum users have solved their similar problems in this manner also. The part is £83ish from Audi and is only available from them.

There is a cheap method to find out for yourself - remove siren unit and get a multimeter to measure the dc voltage between two of the three terminals (can't remember which ones though). Mines was showing about 6.3 volts but I'm not sure what the voltage should be - I assumed 6.8V to be too low though. I'm guessing it should be between 9V and 12V.

If you want removal and installation instructions and diagrams then I'll need your email address to attach the word document.

Hope this helps.

[outside 12]

Hi JR001

Many Thanks for your reply

while starting my car today i found some other symptoms which may further pin down the fault ??? the interior lights were fading in and out when i unlocked the car kinda like they were getting burst's of power ???

does this sound right ?

kind regards

13

[JR001]

Hiya,
I didn't notice any other symptoms along the lines you're describing. Ican't help with this one I'm afraid.

Does your alarm sound come from the driver's side of your boot?

I don't know if your prob may be related to your whole central locking mechanism or not. I have no experience of this aspect. A VAG.COM diag check from your Audi garage would show this hopefully, or even a VW/Audi specialist. Or, buying a fault code reader, get one for about £30 on ebay, you could run a fault code check yourself.
A zero-cost option would be to check your siren battery voltage. If this proves to be okay then you could look to go ahead with a proper diag check.
Are there any other indications?
It is IMO 99% certain that it is your siren battery, it is a common situation with 5-6yr old Audis.

Sorry I can't help any more with your second post!

[diode]

Hi
Sounds like the problem I had My car A4 TDI 2001

It started with the alarm going off at silly times and a quick blast around the block used to sort it out.
Then the fobs refused to work followed by interior lights electric windows and rear doors.

Taking the car to Audi dealer in Sunderland and they blamed the fob first then the fobs and then the ecu all in the space of 10 mins and a cup of coffee that will be #80 quid mate.

It turned out to be a faulty ecu under the carpet on the passenger side.\
This is well covered as a water ingress problem but in my car no water dry as a bone.
I got a new ecu and as it happens I got the old ecu repaired so I now have a spare if anybody wants to buy one.

I also have a VAG lead for sale that works or if you live near me in the North East I can check it out
Hang on I will post the thread if I can find it. http://vwaudiforum.co.uk/forum/showthread.php?t=3629

[dude001]

[quote=outside 12;15574]Hi JR001

Many Thanks for your reply

while starting my car today i found some other symptoms which may further pin down the fault ??? the interior lights were fading in and out when i unlocked the car kinda like they were getting burst's of power ???

does this sound right ?

kind regards

hi jr001 i am having the exact same problem with my car. Can you tell me if you managed to fix the problem and what the cause was. many thanks dude