What causes a SPN 3943 code?

SPN 3943 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 3943 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 3943 active.

How do I fix SPN 3943?

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 3943

J1939 SPN 3943 — Body/Chassis parameter

What it means

SPN 3943 indicates an issue with the Body/Chassis data parameters communicated via the J1939 data link. This usually means the data sent by the body controller is out of range, missing, or incompatible with the chassis controller's expected configuration.