B6 S4 - intermittent key fob and alarm/immobiliser issues

[spen68]

Hi folks, I'll quickly run through a potted history of what's happening - would really appreciate some ideas and suggestions on what to check next.


1) The car alarm goes off intermittently - no noise, just rapid flashing of the hazards until I unlock and re-lock the car.
2) It's twice forgotten the remote key fobs.


• First time I dropped the only key on a hard floor and the next time I went to use it it wouldn't remote unlock the car but I could open the door with the key and start the car OK.
• I bought a new spare key from the Audi dealer and took the car in to have it programmed and left there with 2 keys working.
• Both keys continued to work up until recently - now neither work, but I was still able to unlock the door and start with the key. Central locking works fine when you turn the ignition.


3) Last year I had a brand new battery fitted after the previous one went flat and couldn't get a good recharge.


Where I am now.. Night before last the alarm went off and must have been going all night. In the morning there was enough juice to open the door but turned the key in the ignition and nothing. Battery has been trickle charged over night and this morning it's the same. I get lights on the dashboard but the starter motor doesn't even try and turn it over. I've left it on charge and will try again later but I'm starting to suspect there's something weird going on with the alarm/immobiliser perhaps??


Any ideas folks?


Thanks, Spencer

[Sam]

Check the battery plenum area for a pond and check the front footwells for damp.

[kite]

Scan for faults.
Replace alarm unit. The batteries leak and destroy the circuit board.

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