What causes a SPN 7672 code?

SPN 7672 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 7672 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 7672 active.

How do I fix SPN 7672?

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 7672

Cummins fault code 7672

What it means

SCR Catalyst Efficiency - Catalyst 1, Bank 1 - Effectiveness Below Normal. The Aftertreatment SCR Catalyst system is not meeting the required NOx conversion efficiency.