Two problems related to power assist brake vacuum have been reported for the 1999 Audi A4. The most recently reported issues are listed below.
99v131001/brake booster vacuum valve. The owner is experiencing the same defects that are described in the recall. However, the vehicle identification number was not included in the recall.
While in route to have recall repair on the brake booster by pass, the brakes locked up and the consumer slid into a ditch, damaging vehicle.