What can cause pulsation?
Pulsation can come from more than one brakes branch. Operating conditions, warning behavior, scan data, and physical tests are needed to separate the supported cause from look-alikes.
Plausible causes
- Brake hydraulic, assist, friction, or ABS concern
- Hydraulic or assist fault
- Friction, hub, or wheel issue
Useful next checks
- Photograph warnings, note stationary pedal feel, and view the reservoir through its translucent wall. Record brake-only versus rolling noise and any one-wheel heat or odor; never touch a hot wheel or rotor.
- Full brake/ABS module scan
- Hydraulic leak, fluid, hose, caliper, and assist inspection
Sources and method
This answer provides hypotheses and a verification plan, not a component verdict. Exact repair procedures require authoritative service information for the specific vehicle.
Brake Pulsation Diagnostic Guidelines · NHTSA / Audi