What causes a SPN 799 code?

SPN 799 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 799 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 799 active.

How do I fix SPN 799?

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 799

J1939 SPN 799 — Engine Management parameter

What it means

SPN 799 indicates an issue with the Engine Management Parameter. This code usually relates to an internal ECU error or a communication failure regarding specific engine configuration parameters stored in the Electronic Control Unit memory.