Table 1 shows one common service brakes related problems of the 2001 Audi S4.
| Problem Category | Number of Problems |
|---|---|
| Power Assist Brake problems |
Brake booster check valve fails causing vac hose feeding to booster unit to become totally separated from valve. Result is no brake assist. This happened to me in my 2001 Audi S4!!!! at highway speed!.