What it means
Same as P0564 with the analogue 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 reads the A input from the multi-function switch to identify driver commands. P0581 sets when that input is higher than its plausible range, which can result from a short to supply or a poor connection that disrupts the signal.
Common causes
Most likely first.
- Signal shorted to supply
- Connector pins corroded - high contact resistance
- Supply wire pinched against B+ source
Symptoms
- Cruise control unavailable or disengages
- Cruise-control buttons may not respond
- Check-engine light
How to diagnose it
- Review freeze-frame data and scan-tool switch-status data to see whether the A input remains high with all cruise buttons released.
- Inspect the switch connector and A-input harness for water entry, pin push-back, chafing, or contact with a power wire.
- Using the wiring diagram, measure the A signal at the switch and module connectors while pressing and releasing each cruise-control button.
- With the circuit isolated as specified by the manufacturer, check whether the signal wire is shorted to a supply circuit.
- If the signal and wiring behave correctly at the module connector, compare the module's reported input with the measured value to check for an internal fault.
Common fixes
- Dry, clean, and secure a contaminated cruise-switch connector.
- Repair A-input wiring shorted to a supply wire.
- Replace damaged terminals or correct a pushed-back connector pin.
- Replace a faulty cruise-control switch or stalk if it holds the input high.
- Repair or replace the cruise-control module only after verifying the external circuit.
Can I keep driving?
Normal driving is generally possible, but cruise control may not engage or may disengage without warning. Do not rely on it to maintain speed; use the accelerator and stay attentive to traffic.
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.