What causes a SPN 555 code?

SPN 555 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 555 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 555 active.

How do I fix SPN 555?

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 555

J1939 SPN 555 — Engine Management parameter

What it means

SPN 555 indicates an internal Engine Management parameter error, typically related to a memory or software checksum failure within the ECM.