Help!!! Central Locking Issue & Battery Drain


Registered User
Hey guys, i have a 2001 S3 AMK
I wondered if anyone has experienced a fault I've got to point me in the right direction. I've read many threads and can't find any that have the same issue.
Basically central locking/alarm has been playing up for a little while and now totally given up on me.
Firstly the alarm started randomly just going off for no apparent reason.
Then sometimes I'd get it work and it wouldn't lock or arm the alarm.
I replaced the battery in the key thinking this was the fault however after a couple of days of working fine it totally stopped. But more than that I'm also getting a power drain that kills the battery after 4-6 hours. Also fuse 37 blew one morning after having the car running.
Also when I drive the locking vacuum pump is trying to work as I here a clicking for 10 secs then nothing then starts again.
The central locking doesn't work even with the key, it also doesn't work from the button on the inside of the drivers door. It doesn't seem to have effected any other electrics (windows etc)
I've taken the pump apart to inspect and all seems intact. However not ruling out that has a fault.
I've checked fuses are not blown
I'm wondering if it maybe a module fault, ECU fault, is there a relay that controls it? Or maybe a broken wiring somewhere?
If anyone's got any ideas it'd be much appreciated before I pay out £££ to an auto electrician.
Thanks in advance.
Last edited:

Alan Gunn

Registered User
Sounds like the ccm unit under the carpet on the passenger side front.
Is the carpet wet/damp on that side at all.


Registered User
Alan thanks for your suggestion as I hadn't thought of that.
I've just check the carpets and they are bone dry, I won't rule out looking further though as the unit could be still at fault.


Registered User
Give it a scan with vcds. I scanned mine and it found old faults from the previous owner about a central locking leak.