What causes a P0566 code?

P0566 can be triggered by several issues — see the verified probable causes and step-by-step diagnostics shared by mechanics and owners on OBDIY.

Can I drive with a P0566 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with P0566 active.

Follow the step-by-step diagnostic on this page, then read the verified fixes contributed by other Heavy Truck owners — the answer marked "Verified Cause" worked for the original poster.

OBDIY

OBD-II

P0566

Cruise Control Off Signal Performance Fault

What it means

The Engine Control Module (ECM) detects an invalid or out-of-range voltage signal from the Cruise Control 'OFF' switch circuit, indicating a potential hardware failure or wiring issue.