The P0571 code indicates that the engine control module has detected a malfunction in the brake light switch circuit. This typically occurs when the signal from the brake pedal switch is missing, intermittent, or logically inconsistent with other vehicle inputs.
The internal electrical contacts of the switch have worn out or failed mechanically.
Frayed, corroded, or broken wires in the circuit leading to the switch or the control module.
A blown fuse has interrupted the power supply to the brake light switch circuit.
The switch is physically misaligned, preventing the brake pedal from triggering the contact.
An internal failure within the engine control module's signal processing circuit.
Yes, many modern vehicles require a confirmed brake signal to engage the starter motor for safety.
No. While some may suggest replacing the PCM, this code is almost always caused by a faulty switch, wiring issues, or a blown fuse.
It is potentially unsafe because the brake lights may not function, and the cruise control may not deactivate when the brakes are applied.