One problem related to battery dead has been reported for the 2001 Audi TT. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2001 Audi TT based on all problems reported for the 2001 TT.
Battery was dead. Replaced battery and by next morning the new battery was dead. Turns out that the heated seats were short circuiting and was draining the battery even when shut off. Disconnected the fuse. Found out that in order to get fixed could cost in excess of $1000 since it requires taking the dashboard apart.