Various electrical faults, such as glitches with remote locking system, power windows and various drivetrain-related sensors. Various squeaks and rattles common. Water entering sealed headlights. Engine ignition coils failure issue supposedly fixed by now, but some still report problems. Major problem with oil sludge accumulation after 100,000 kms, largely with pre-2005 turbo models, leading to total engine failure, but Audi simply added larger oil filter to all post-2005 cars now and recommends synthetic oil.
