Brake-pedal information can be used by several vehicle systems. P0571 relates to the brake/cruise-switch circuit, while P0572 and P0573 distinguish low and high circuit conditions. Keep the manufacturer’s full wording: an implausible signal is a diagnostic finding, not a replacement instruction.
Why a simple lamp check is only part of the picture
Tell the workshop whether the brake lamps operate consistently, stay on, or fail intermittently. Also record any cruise-control problem, starting restriction or warning that appears with the same event. Do not drive with defective brake lamps or an abnormal braking response; arrange an appropriate assessment.
Ross-Tech’s VAG P0571 entry includes wiring, fuses, the brake switch and bulb faults among the possibilities. It also notes that an incorrect bulb specification can matter on applicable vehicles. These checks prevent a body controller being blamed before the lamp circuit is understood. P0571 reference.
A useful enquiry includes
- The vehicle, year, engine and full scan report.
- Which lamps work, and whether any were recently changed.
- Whether the warning follows pedal movement or appears without touching the pedal.
- Details of switch replacement, adjustment or wiring repairs already attempted.
Switch installation and adjustment procedures differ. A replacement fitted incorrectly can leave the original symptom unresolved. Diagnostic live data should be compared with the actual pedal and lamp behaviour before a controller assessment is requested.
For help with the electrical investigation, contact AXION. Further reading is available in our body-module collection.
Reviewed September 2026. Use the complete manufacturer-specific fault description and vehicle repair information.