What causes a P0490 code?

P0490 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 P0490 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with P0490 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

P0490

EGR Control Circuit High Voltage Fault

What it means

The Engine Control Module (ECM) has detected an abnormally high voltage signal returned from the Exhaust Gas Recirculation (EGR) valve control circuit, indicating a potential short to power or component failure.