P0573 Cruise Control/Brake Switch A Circuit High

P0573 points to a high condition in Cruise Control or Brake Switch A circuit. The controller sees brake or cruise-cancel voltage above 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 ignore a high brake-switch signal because it can disable cruise and affect shift or start interlocks.

Symptoms of P0573

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 P0573

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

Review brake switch A and B states, stop lamp operation, cruise cancel status, vehicle speed, freeze-frame data, and related brake switch codes.
Inspect for short-to-voltage faults, open grounds, switch misadjustment, stuck pedal hardware, connector corrosion, and harness damage near the pedal.
Verify the switch changes state correctly and is not stuck high with the pedal released.

Related OBD-II codes

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