What causes a P2456 code?

P2456 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 P2456 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with P2456 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

P2456

DPF Differential Pressure Sensor Circuit Intermittent

What it means

The Engine Control Module (ECM) has detected an erratic or intermittent signal voltage from the Diesel Particulate Filter (DPF) differential pressure sensor which measures the pressure drop across the filter.