What causes a SPN 5929 code?

SPN 5929 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 5929 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 5929 active.

How do I fix SPN 5929?

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 5929

Cummins fault code 5929

What it means

Active Grill Shutter (AGS) Damper - Abnormal Update Rate. This indicates the Engine Control Module (ECM) has lost communication with the grill shutter actuator or the actuator is not responding to commands.