Cruise Control Input Circuit High
The Powertrain Control Module (PCM) has detected a voltage signal from the cruise control input circuit that exceeds the maximum expected threshold. This typically indicates a short to voltage or a malfunctioning cruise control switch assembly.
This code primarily affects the cruise control system and does not impact the vehicle's core drivability or safety. It can be diagnosed and repaired at your convenience.
Common symptoms
- Check engine light is illuminated
- Cruise control system is completely inoperative
- Cruise control indicator light fails to illuminate on the dash
- Inability to set or maintain a cruising speed
- Other steering wheel controls may malfunction if sharing a clock spring
Likely causes
- Faulty cruise control multi-function switch
- Short to voltage in the cruise control input circuit wiring
- Damaged or failing steering wheel clock spring
- Corroded or loose electrical connectors in the cruise control circuit
- Blown fuse related to the cruise control system
- Faulty Powertrain Control Module (PCM) (rare)
What to check before replacing parts
Connect a scan tool and monitor the cruise control switch PID data.
Look for: Look for the switch status to remain 'ON' or show high voltage even when the buttons are not being pressed.
Visually inspect the wiring and connectors associated with the cruise control switch and steering column.
Look for: Check for chafed wires, pinched harnesses, or corroded pins that could cause a short to power.
Test the cruise control system fuses.
Look for: Identify if any related fuses are blown, which could indicate a severe short circuit in the system.
Perform a continuity and resistance test on the steering wheel clock spring.
Look for: An open circuit or high resistance reading when turning the steering wheel indicates a faulty clock spring.
Measure the voltage and resistance directly at the cruise control switch.
Look for: Compare the multimeter readings to the manufacturer's specifications; out-of-spec resistance when buttons are pressed confirms a bad switch.
This page explains the generic P0577 definition and is general reference information, not a diagnosis for your specific vehicle. Actual causes, severity, and repairs vary by make, model, engine, and mileage — always confirm with a scan tool and a qualified technician before replacing parts.
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