What causes a P1046 code?

P1046 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 P1046 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with P1046 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

P1046

High error fault of FAFPD diagnosis in idle

What it means

The Engine Control Module (ECM) has detected that the fuel rail pressure is significantly higher than the commanded setpoint while the engine is idling.