What it means
Same as P0575 with the input voltage above the plausible range. Wiring faults of this kind typically come from chafing, water ingress at connector seals, or pin push-back — a wiggle test on the harness while the code is active often confirms the location.
At a glance
- Usually lights the check-engine light
How it works
The cruise-control module monitors a dedicated input, often the set or resume button circuit, for the driver's command. P0577 sets when the input voltage rises above its plausible range, which can happen if the signal wire contacts a supply voltage.
Common causes
Most likely first.
- Input shorted to supply
- Connector pins corroded - high contact resistance
- Supply wire pinched against B+ source
Symptoms
- Cruise control may not engage or may stop working
- Cruise control buttons may respond inconsistently
- Check-engine light may come on
How to diagnose it
- Record freeze-frame data and monitor the cruise input voltage or button status to confirm it is high when the code sets.
- Inspect the set/resume switch wiring and connectors for pinched insulation, pin push-back, moisture, or contact with a powered wire.
- Use the wiring diagram to test the input circuit for a short to supply and check connector terminals for corrosion or damage.
- Move the harness gently while watching live input data to locate a short that appears only when the wiring shifts.
- Test switch output and module input against the manufacturer's specification before diagnosing the module itself.
Common fixes
- Repair wiring pinched against a supply source or shorted to a powered circuit.
- Clean or replace damaged connector terminals and restore the connector seal.
- Replace a set/resume switch that produces an out-of-range signal.
- Repair or replace the receiving module if the circuit and switch pass testing.
Can I keep driving?
Basic driving is usually unaffected, but cruise control may not work or may respond unpredictably. Do not depend on cruise control until the high input fault is corrected.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.