What causes a SPN 7091 code?

SPN 7091 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 7091 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 7091 active.

How do I fix SPN 7091?

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 7091

Cummins fault code 7091

What it means

Aftertreatment 1 Control Module - Abnormal Update Rate. This indicates the ECM has lost communication with the Aftertreatment Control Module (ACM) over the J1939 data link.