What causes a SPN 3942 code?

SPN 3942 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 3942 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 3942 active.

How do I fix SPN 3942?

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 3942

J1939 SPN 3942 — Body/Chassis parameter

What it means

J1939 Body/Chassis Parameter Data Not Received or Invalid Data. This code indicates a communication mismatch or missing data regarding specific body-builder parameters (such as PTO status, liftgate position, or specialized chassis configurations) across the vehicle network.