P0571Powertrain
Brake switch circuit malfunction
Where to start
The brake light switch circuit. A recognisable symptom: cruise control will not engage and the gearbox will not leave Park. The switch is cheap, sits on the pedal and is replaced without removing anything — but more often it has merely slipped out of adjustment.
A code is not a diagnosis. It says which check failed, not which part to replace. Clearing it without repair only means the car will report it again in a few trips.
How to put together a report a mechanic will actually read
We have a detailed piece on thisCruise control gone: codes P0500, P0501, P0504, P0571
How the code is built
Letter — the systemPowertrain: engine and transmission
Common or the maker's ownGeneric code: the same on every car
Which part of the engineIdle and auxiliary systems
Number of the faultThe serial number inside that group — it does not say how serious the fault is
All codes in «Idle and auxiliary systems»
How it feels behind the wheel
The same fault shows itself in different ways. Each sign below says what to look at in the live data.
How the app helps
CarScan reads this code from your car through an OBD-II adapter, shows whether it is active now or only stored, names the module that reported it, and puts it into a plain-text report for your mechanic.