What causes a P1250 code?

P1250 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 P1250 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with P1250 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

P1250

Cylinder 4: Injector spill valve short circuit across injector

What it means

The ECM has detected a short circuit across the two terminals of the fuel injector spill valve for cylinder #4, preventing the injector from firing correctly.