What causes a SPN 805 code?

SPN 805 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 805 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 805 active.

How do I fix SPN 805?

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 805

J1939 SPN 805 — Engine Management parameter

What it means

SPN 805 indicates a persistent error in the Engine Management Parameters stored in the ECU memory. It signifies that the control unit has detected data that is out of range, missing, or inconsistent with the engine's required configuration.