OBD-II code · Powertrain (generic)
P0571 Brake Switch "A" Circuit Malfunction
The brake light switch signal seen by the ECU is implausible — for example, both contacts active simultaneously, or no signal change despite the brake pedal being pressed (cruise control engages and disengages on this signal). On many cars also disables shift interlock.
Is it safe to drive with P0571?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyBrake switch failed (worn contacts, internal break)
- PossibleSwitch misadjusted (does not actuate at correct pedal position)
Repair at a glance
- Difficulty
- Easy
- DIY friendly
- Often, with basic tools
- Typical labour
- 0.2–1 h
- Emissions test
- Usually unaffected
- Parts involved
- Brake Light Switch, Brake Light Switch Wiring
Related codes
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.