What causes a SPN 3399 code?

SPN 3399 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 3399 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 3399 active.

How do I fix SPN 3399?

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 3399

J1939 SPN 3399 — Body/Chassis parameter

What it means

J1939 SPN 3399 typically refers to a generic 'Configuration Conflict' or 'Invalid Data' received from a body or chassis controller. It indicates that the ECM is receiving data from the chassis that it does not recognize or that contradicts its internal programming.