One problem related to hazard flashing warning light unit has been reported for the 1999 Audi A4. The most recently reported issues are listed below.
When driving and upon depressing brake pedal when attempting to stop, experienced complete brake failure without prior warning which caused extended stopping distance. Also, directional signal and emergency lights malfunctioned.
| Headlight Concealment Device problems | |
| Hazard Flashing Warning Light Unit problems | |
| Hazard Flashing Warning Light problems | |
| Brake Light problems |