All codes
Brake Switch A Circuit Malfunction
P0571 indicates a fault related to brake switch a circuit malfunction. Learn the likely causes and a practical diagnostic order before replacing parts.
What you may notice
Symptoms
- 01Warning light may illuminate
- 02System function may be impaired
- 03Symptoms depend on the vehicle and fault conditions
Where to look first
Common causes
- 01A misadjusted brake switch, failed lamp circuit, or damaged wiring can alter the brake input.
- 02Connector, wiring, ground, or supply-voltage fault
- 03Vehicle-specific mechanical or control problem
A sensible sequence
Best diagnostic order
- 01Record codes and freeze-frame data
- 02Confirm brake lamps operate correctly and compare both brake-switch states while pressing the pedal; inspect adjustment and wiring.
- 03Compare results with vehicle-specific service information
- 04Verify the repair and monitor readiness
Step by step
What to check and repair
- 01Confirm brake lamps operate correctly and compare both brake-switch states while pressing the pedal; inspect adjustment and wiring.
- 02Repair the confirmed cause and retest under the original fault conditions
Read the signals
Live-data clues
Brake switch states
- Typical behavior
- Plausible for the current operating condition and vehicle specification
- Possible clue
- An implausible value or dropout helps localize the fault
| Parameter | Typical behavior | What it can suggest |
|---|---|---|
| Brake switch states | Plausible for the current operating condition and vehicle specification | An implausible value or dropout helps localize the fault |
What P0571 means
P0571 is an OBD2 diagnostic trouble code for brake switch a circuit malfunction. The code identifies a detected condition, not a confirmed failed part.
Diagnostic direction
Confirm brake lamps operate correctly and compare both brake-switch states while pressing the pedal; inspect adjustment and wiring.
Before clearing the code
Save stored and pending codes and freeze-frame data. Confirm the exact vehicle procedure and specifications, repair the verified cause, and repeat the applicable test or drive cycle.