P0572 Cruise Control/Brake Switch A Circuit Low

P0572 indicates a low condition in Cruise Control or Brake Switch A circuit. The controller sees brake or cruise-cancel voltage below the expected range.

Code details

Generic OBD-II · P0

System: Speed / Idle
Code type: Generic (SAE / ISO controlled)
Standard: SAE J2012 / ISO 15031-6

Diagnostic boundary

A diagnostic trouble code reports that a monitored test failed. It does not prove one specific part is bad, and manufacturer logic can add vehicle-specific conditions.

Do not replace cruise components until brake switch A power, ground, adjustment, and stop lamp operation are verified.

Symptoms of P0572

Unstable, high, or low idle, or stalling.
Erratic speedometer, cruise-control, or shift behaviour.
Check-engine light with a hesitation or surge.

Common causes of P0572

A dirty throttle body, idle-control valve, or throttle-position sensor.
A failing vehicle-speed or wheel-speed sensor, or its wiring.
Vacuum leaks or a related sensor forcing the idle/speed strategy.

Useful checks before replacing parts

Compare brake switch A state, brake switch B state, stop lamp operation, cruise cancel status, vehicle speed, and freeze-frame conditions.
Inspect for short-to-ground faults, open power feed, misadjusted brake switch, damaged pedal wiring, blown fuses, and corroded terminals.
Press and release the brake pedal while watching both switch circuits to confirm clean transitions.

Related OBD-II codes

These nearby speed / idle entries can help compare wording and pin down the fault area.