Audi A4 B6 Common Problems

The B6 uses a pneumatic pump in the trunk to lock the doors.

Pixels missing in the center display, intermittent or dead gauges (speedo, fuel), or the entire cluster goes dark. Cause: Poor internal solder joints and failing driver transistors. Fix: Professional rebuild service (approx. $200–$400) or DIY resoldering (requires skill). Tip: If the cluster fails completely, the car may not start due to immobilizer issues. audi a4 b6 common problems

The Quattro automatic is much better, but not perfect. The B6 uses a pneumatic pump in the trunk to lock the doors