P0577
Cruise Control Input Circuit High.
- Generic
- Powertrain
- Generic code
- Low severity
How this code is built
- P
- SystemPowertrain
- 0
- Defined bySAE, the same on every car
- 5
- AreaVehicle speed, idle control and auxiliary inputs
- 77
- FaultThe specific fault in that area
What it means
P0577 is the SAE J2012 generic code for a Cruise Control Input Circuit High fault. The control unit monitors the voltage on the cruise control switch or input circuit and saw it higher than the expected range, which points to an open circuit, a short to voltage or a faulty switch. The exact circuit layout, and which module monitors it, varies by model.
Symptoms
- Cruise control will not engage or set
- Cruise control cancels itself unexpectedly
- Cruise control warning light or message on the dash
- Steering wheel or stalk cruise buttons unresponsive
- Engine management light may be on
- Other steering wheel controls may also stop working on some models
Possible causes
- Faulty cruise control switch or steering wheel/stalk control assemblylikely
- Damaged, corroded or loose wiring or connector in the cruise control input circuitlikely
- Short to voltage or open circuit (for example a broken ground) in the input signal wiringpossible
- Worn or damaged clockspring or contact ring in the steering column, where fittedpossible
- Water ingress or contamination in the switch or connectorpossible
- Faulty control unit or input circuit within the modulerare
How to diagnose
- Read all stored codes and freeze frame data, and note whether other body or steering wheel control faults are present
- Check the cruise control buttons and note which functions work, if any
- Inspect the switch, stalk and connectors for damage, corrosion, moisture or loose pins
- Check the wiring between the switch and the control unit for chafing, breaks or a short to a power supply, following the model's wiring diagram
- Measure the supply, signal and ground at the switch connector against the manufacturer's specification
- Check the switch's resistance or signal values in each button position against specification
- Inspect the clockspring or column connections if fitted, following the manufacturer's procedure
- Clear the code and road test to see whether it returns, and only suspect the control unit once the wiring and switch are proven good
How to fix
- Replace the faulty cruise control switch or control assembly
- Repair or replace damaged wiring, and clean or replace corroded connectors
- Correct the short to voltage or restore the open ground in the circuit
- Replace the clockspring or contact ring if it is found faulty
- Dry out and clean any contaminated connectors, and trace and fix the source of water ingress
- Repair or replace the control unit only after all other causes are ruled out
Can I keep driving?
Low severity
The car is normally safe to drive as only the cruise control function is lost. Book it in for repair at your convenience, but have it checked sooner if other steering wheel controls or warning lights are also affected.
Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.