What it means
The control module detects a low input in the cruise control multi-function input A circuit.
At a glance
- Usually lights the check-engine light
How it works
The cruise-control module reads the A input from the multi-function switch to identify commands such as set, resume, or cancel. P0580 sets when that input is lower than the module expects, often because the signal is grounded or the connection has excessive resistance.
Common causes
Most likely first.
- Signal shorted to ground
- Connector pins corroded - high contact resistance
- Harness chafing through insulation
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
- Check freeze-frame data and scan-tool switch-status data to confirm whether the A input stays low or changes when a cruise button is pressed.
- Inspect the cruise-control switch or stalk connector and nearby harness for corrosion, loose pins, or insulation rubbed through to ground.
- With the circuit diagram, check the A signal at the switch and module connectors while operating the controls, looking for a persistently low reading.
- Check for continuity to ground on the isolated signal wire to find a short, and inspect connector pins for high resistance or poor contact.
- If the wiring and switch signal are sound, compare the module's input reading with the measured circuit state to assess a module fault.
Common fixes
- Clean and secure corroded or loose cruise-switch connector terminals.
- Repair chafed A-input wiring that is shorted to ground.
- Replace a faulty cruise-control switch or stalk if its output remains low.
- Repair a damaged connector or pin with poor contact.
- Replace or repair the cruise-control module only after the input circuit checks out.
Can I keep driving?
The fault usually disables cruise control rather than affecting normal throttle operation. Drive using the accelerator and be prepared for cruise control to be unavailable or to disengage unexpectedly.
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.