What causes a P0457 code?

P0457 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 P0457 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with P0457 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

P0457

P0457 Evaporative Emission System Leak Detected (Fuel Cap Loose/Off)

What it means

This code indicates the Engine Control Module has detected a significant pressure loss in the evaporative emission system, typically associated with a missing or improperly sealed fuel filler cap.