What causes a P1565 code?

P1565 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 P1565 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with P1565 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

P1565

Idle diagnostic speed error fault

What it means

The Engine Control Module (ECM) has detected that the engine idle speed is outside of the pre-programmed parameters, meaning it is either too high or too low for the current engine state.