P0577 Cruise Control Input Circuit High

P0577 indicates a high condition in the cruise control input circuit. The controller sees cruise input 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 condemn the controller before checking the cruise input circuit for short-to-voltage and ground faults.

Symptoms of P0577

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 P0577

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 cruise input voltage, switch states, shared resistor circuit behavior, brake switch status, vehicle speed, and freeze-frame conditions.
Inspect for short-to-voltage faults, open grounds, damaged clockspring wiring, stuck switches, connector corrosion, and liquid intrusion.
Monitor live data while operating cruise switches to confirm whether the input is stuck high or only high for one request.

Related OBD-II codes

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