What causes a P2425 code?

P2425 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 P2425 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with P2425 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

P2425

EGR Cooler Bypass Control Circuit Open

What it means

The Engine Control Module detects an open circuit in the EGR cooler bypass valve control loop, which can lead to improper exhaust gas cooling and elevated NOx emissions.