gregstormd

We took our 2002 TT 225hp (40,000 miles) to our mechanic (not the dealer, but an VW/Audi specialist who we trust) after the battery completely died, and were told that our car had a slow parasitic leak. It turns out the leak was faster than they thought, as the new battery died just days later.

They haven't been able to find the cause, and we're hoping the exact symptoms may ring a bell with someone here:

- 380 ma drain after 30 minutes
- drain drops to .028 after 45 min to 1 hr

The next step in the diagnosis is for them to dismantle the dash and check the instrument cluster, but the $$$ are starting to add up on finding this leak.

We did take our TT to a dealer about a year ago when the gas gauge stopped working, but they said the computer indicated it was the tank sensor that had failed, and that there was nothing wrong with the cluster.

Thanks in advance!

Greg D

RVTS4

Hmmmm maybe you could try pulling some fuses to see if it goes away. Or some sensor plugs. That would help narrow it down.

TTinCT

Check your brake light switch....it could be faulty and stuck in the on position.

AudiTTR225

any aftermarket accessories like bluetooth, radar detector, head unit, amplifier, etc? anything like that could be improperly wired to a 12v constant rather than switched power supply, draining your battery.

hahnmgh63

All the above are great things to check so I'll throw in something different since you gave the time braced on a time frame. What about the after run coolant pump? Runs when the engine is shutdown for a while then should quit unless the temp sensor is giving it bad data and sending a little juice to it even after the engine is cool.

gregstormd

Thanks for all the suggestions. Our mechanic will be checking them tomorrow, though they say it's most likely the instrument cluster. Apparently the tank sensor error message can also mean there's a fault with the cluster (a detail that the Audi dealer failed to tell us!)

I'll post the outcome.

gregstormd

TTinCT was right on the money--it was the brake light switch. We still may end up replacing the cluster because of the malfunctioning fuel gauge, but at least it's drivable now!

Thanks again for everyone's input.