2000 Passat Stationwagon: Battery Drain

[deMeadville]

Greetings!

Close friend's 2000 Passat Stationwagon seems to have battery drain after several days of non-use. Car has undergone a lot of R/R in last few years, most recently being the heating core and both water pumps. According to AAA, the battery and alternator are fine and there is no evidence of any door "light switches" being stuck "on".

Any clues from you fine gurus?

Thanks,

...m...

[Dmitry at Pelican Parts]

Hello - I was able to find some info for you in regards to the battery draining. Someone suggested that it sounds like you may have abnormal parasitic battery drain caused by a module not going to sleep like it should, after the car powers off - perhaps take it to a dealer for a proper diagnosis. If you have a scan tool, it could also help with future diagnoses of issues. Here is a link if you're interested Schwaben Pro Scan Tool for Audi and VW

Current drain on the battery can be checked with an ammeter. Make sure the ignition is off, then disconnect one of the battery cables. Connect one ammeter lead to the battery and the other to the cable. The normal current drain on most vehicles should be about 25 milliamps or less. If the key-off drain exceeds 100 milliamps, there's an electrical problem that requires further diagnosis.

Finding the hidden current drain can be time consuming. The easiest way to isolate the problem is to pull one fuse at a time from the fuse panel until the ammeter reading drops. This will tell you which circuit is draining the battery. Then you have to check the wiring and each of the components in that circuit to pinpoint the problem.

Hope this helps you a bit - best of luck!

[deMeadville]

Dear Dmitry,

Thanks so much for your timely assessment of this problem. I have passed your recommendation on to the owner and hopefully your expertise will lead getting this issue resolved.

Best wishes,

...m...