What causes a P0593 code?

P0593 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 P0593 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with P0593 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

P0593

Cruise Control Multi-Function Input 'B' Circuit High

What it means

The Engine Control Module (ECM) has detected a voltage signal from the cruise control switch 'B' circuit that is higher than the calibrated range, typically indicating a short to power or a faulty switch.