crono35

it's worth pressure testing at least once just to see if the repair is in an easy to do area. Just pressurize the line going from the evap canister to the filler neck (I used a bicycle pump and cut up an old tube, sealed off one end, and clamped the other end around the pipe). This + soapy water found the leak in about half an hour.

I wasn't able to find the leak with the filler off the car because my old cap wasn't holding pressure. If you haven't tried replacing the cap yet, I'd recommend doing so... I went through 2 used oem caps, 2 new aftermarket caps before splurging on a new OEM. Never would have found the issue if I didn't.

clancy

Thanks for the tips. Also, I would normally never buy a gas cap from Audi, now I will.

crono35

If you have vag-com and run group 71 in basic settings, you can actually hear the cap hissing. I actually ran the test halfway and turned the car off so I could hear it better, and there definitely was a hiss coming from the cap- telltale sign it needs replacement.

clancy

I have VCDS but continue to forget to use it. Thanks