P0571 to P0573 and P0504: brake pedal switch A
The main brake pedal switch (A) has a circuit fault or reads low or high, or it disagrees with the second brake switch (B) about whether the pedal is pressed (P0504).
SeverityHighCarrying on can cause expensive damage, so deal with it now.
Can you keep driving?Only as far as the workshopWhat does P0571 mean?
On most cars the main brake switch lights the brake lights and tells the computers that the driver is braking. The engine computer uses it to cancel cruise control and, on cars with an electronic throttle, to cut engine power if the accelerator and brake are pressed together; the gearbox uses it to release the lever from park. Many cars have a second switch so the computer can cross-check them, and P0504 is that check failing. A faulty switch can leave the brake lights off, or on all the time.
What causes P0571?
- A brake switch out of adjustment, often after pedal or brake work
- A failed switch, or a broken plastic stop on the pedal that the switch presses against
- A blown brake light fuse or failed bulbs, on some cars
- A damaged wire or connector above the brake pedal
What to check first for P0571
- Have someone press the brake pedal while you look at all the brake lights
- Check whether the brake lights stay on with the pedal released
- Inspect the switch above the brake pedal and the plastic stop it touches
- Watch both brake switch signals on a scan tool while pressing the pedal slowly
Can you drive with P0571?
Drive only to a workshop, and only if the brake lights work normally, because drivers behind you rely on them. If they do not come on, or stay on, do not drive until the switch is fixed; the brakes themselves still work, but cruise control and the gear lever may not.
Since May 2018 an engine warning light that stays on is a major defect at the MOT, so the car fails until the fault is fixed.
Codes on this page
- P0504Brake Switch "A"/"B" Correlation
- P0571Brake Switch "A" Circuit
- P0572Brake Switch "A" Circuit Low
- P0573Brake Switch "A" Circuit High
Related codes
Checked on · Rafael Soares
These are the generic meanings every manufacturer shares. Each brand adds its own detail, so your car's handbook, its service information and a qualified mechanic have the last word. OdoKeep has no connection with any manufacturer, and the app does not read codes from the car.
