What causes a SPN 820 code?

SPN 820 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 820 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 820 active.

How do I fix SPN 820?

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 820

J1939 SPN 820 — Engine Management parameter

What it means

Source Address 185 (Engine Management) communicating via the J1939 data link has reported a parameter error or is failing to communicate correctly.