What causes a SPN 502 code?

SPN 502 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 502 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 502 active.

How do I fix SPN 502?

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 502

J1939 SPN 502 — Engine Management parameter

What it means

SPN 502 indicates a 'Maximum Vehicle Speed Limit' or 'Engine Speed/Load' plausibility error. It suggests the Engine Control Module (ECM) detected a vehicle speed that exceeds the programmed limit or is inconsistent with other engine parameters.