P0571: Brake Switch "A" Circuit
P0571 means Brake Switch "A" Circuit. The brake pedal switch tells the engine computer when the brakes are applied. This code points to a fault in the brake switch "A" circuit.
Can I keep driving? Limit driving and diagnose promptly. Continued driving can cause damage, stalling or limp mode.
Common symptoms
- Brake lights not working or always on
- Cruise control not working
- Push-button start may not work (vehicles that require pressing the brake)
- Automatic transmission may not leave Park
Possible causes
- Failed or misadjusted brake light switch
- Blown brake light fuse
- Wiring or connector fault
- Failed brake bulbs (on some vehicles)
How to diagnose P0571
- Check whether the brake lights work.
- Check the fuse.
- Check the switch adjustment and operation with a scan tool or meter.
Working brake lights are a safety item. Fix this before driving more than necessary.
What the code means, digit by digit
Generic codes have the same definition on every OBD-II vehicle (petrol cars from model year 1996 in the US, 2001 in the EU; diesels later). Manufacturers can add their own enhanced codes; those are not listed here.
General guidance only. Fault codes describe what the engine computer saw, not which part failed: confirm with testing before replacing parts, and follow the vehicle's service information.