P0581 Cruise Control Multi-Function Input A Circuit High

P0581 indicates a high condition in Cruise Control Multi-Function Input A circuit. The input A signal is 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 PCM or BCM until the input A wiring and switch network are tested.

Symptoms of P0581

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 P0581

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 input A voltage, switch states, reference voltage, ground path, brake switch data, vehicle speed, and freeze-frame data.
Inspect for short-to-voltage faults, open grounds, damaged clockspring wiring, stuck switch contacts, liquid intrusion, and connector corrosion.
Operate each input A function while watching live data to see whether the signal is stuck high or only high for one switch.

Related OBD-II codes

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