What causes a SPN 6846 code?

SPN 6846 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 SPN 6846 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 6846 active.

How do I fix SPN 6846?

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

J1939 SPN

SPN 6846

Cummins fault code 6846

What it means

SCR Ammonia Sensor - Excessive Ammonia Concentrations Detected. This indicates the ammonia sensor has detected NH3 levels exiting the SCR catalyst that exceed pre-defined limits.