Flat Battery

M

MissSpentYouth

Member
Well I have a long running flat battery problem with my 52 plate A2 Tdi with 130K on the clock.

If I leave the car for a few days she wont start as the battery is flat, I have replaced the battery some time back. If I put an ammeter in line with the battery terminal I get 460mA with everything off keys out doors shut locked up etc hence flat battery.

I have an issue with a passenger front window which if I remove the door card and pull the connector off the motor this drops the current drawn by 50mA will source a new one shortly.

Pulling the fuses makes little difference only a small drop when I remove the central locking fuse.

Interior and boot lights all off.

If I disconnect the central convienience module completely then I get a small drop also replaced it with a known good unit no difference. If I pull the codes I do get some central convienence module errors hence disconnecting it and swapping it out to no avail.

What else is live when the ignition is switched off ?

How can I disconnect the alarm ?

Any help much appeaciated as I am really stumped on this one

Any one have a wiring diagram ?

cheers Ben
 
MissSpentYouth said:
Well I have a long running flat battery problem with my 52 plate A2 Tdi with 130K on the clock.

If I leave the car for a few days she wont start as the battery is flat, I have replaced the battery some time back. If I put an ammeter in line with the battery terminal I get 460mA with everything off keys out doors shut locked up etc hence flat battery.

I have an issue with a passenger front window which if I remove the door card and pull the connector off the motor this drops the current drawn by 50mA will source a new one shortly.

Pulling the fuses makes little difference only a small drop when I remove the central locking fuse.

Interior and boot lights all off.

If I disconnect the central convienience module completely then I get a small drop also replaced it with a known good unit no difference. If I pull the codes I do get some central convienence module errors hence disconnecting it and swapping it out to no avail.

What else is live when the ignition is switched off ?

How can I disconnect the alarm ?

Any help much appeaciated as I am really stumped on this one

Any one have a wiring diagram ?

cheers Ben
Click to expand...

There were a few members with faulty head units that keeps drawing power from the battery at ignition off. Try disconnecting yours and see if that is the problem.
 
Hi Humps, Pulled the head unit no difference :-( I suspect pulling the fuse would have identified a problematic head unit. thanks anyway Ben.
 
Well in desparation I pulled every fuse out of the car and let it sit for 5 minutes and hey presto current drain fell to 0 result. Traced it back to the two fuses the drive the central locking 36 & 42 basically with those out if you leave the car for a minute without opening or closing any door or disconnecting anything then current drain falls to 50mA. Traced it back to the comfort control module if I pull the main input connector off that then I can reinstall the two fuses and after a minute current drain falls to 50mA with the car all locked up doors closed etc. With the CCU fully connected up then current drain only falls to 170mA. If I remove my dodgy CCU (it has VAGCOM errors) and intal LAU's known good unit then current drain falls to 50mA after a minute result :) So after all that it was the damn CCU in the first place which was the first thing I tried to replace but got completely confused by this waiting a minute for steady state conditions if you open or close a door or disconnect or reconnect a door window module then current drain shoots back up and you have to wait a minute for it to settle down again. Will send my unit off to Lau to get it repaired. cheers Ben.
 
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Good on ya Pal, well done and thanks for letting us know, I'm sure it will help someone along the A2 journey :)


Cheers
Sarge
 
It's under the passenger footwell (if you pull the carpet up, you will find a hidden access panel). If you DO open it up, make a note of everything you find written on it.

The CCU controls the locks, internal lights, window winders (and climate control?). The car will work without it, but you won't be able to lock etc.
 
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