One problem related to power window has been reported for the 2001 Audi Quattro. The most recently reported issues are listed below.
Trouble occurred with both driver and passenger windows, but at different times. Passenger window was still under warranty at the time. Window would not close properly and then would spontaneously open. Attempts to close it entirely were often not successful. Motor was replaced on both windows-one under warranty, the other not. A second occurrence with driver window required another costly repair, although the cause was different. This happens also currently with rear passenger window when it is cold. I have had nothing but mechanical issues with this vehicle.