What causes a SPN 3993 code?

SPN 3993 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 3993 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 3993 active.

How do I fix SPN 3993?

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 3993

J1939 SPN 3993 — Body/Chassis parameter

What it means

SPN 3993 typically refers to an 'Unexpected Configuration' or 'Inconsistent Parameter' related to Body/Chassis data received over the J1939 network. It indicates the engine or transmission controller is receiving body integration data that does not match its programmed logic.