What causes a P1846 code?

P1846 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 P1846 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with P1846 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

P1846

Upstream NOx sensor ECU-ID message high rate fault

What it means

The engine control module (ECM) or Aftertreatment Control Module (ACM) is receiving data packets from the Input (Upstream) NOx sensor at a frequency higher than the specified J1939 protocol limits.