Right. I have a 97 Audi A4 tdi and I've just had the alternator replaced, since then the alarm seems to randomly go off. Once parked up it will be ok for 10-15mins then the alarm will sound, if I turn it off and on again it'll do the same 10 mins later. Could this be caused by a knackered battery? I'm thinking the battery is dropping voltage, causing the alarm to sound. The battery is fine when driving along though. Basically trying to figure out if this is related to the alternator incident, or something different. Cheers for any help.