What causes a SPN 3874 code?

SPN 3874 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 3874 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 3874 active.

How do I fix SPN 3874?

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 3874

J1939 SPN 3874 — Body/Chassis parameter

What it means

The SPN 3874 indicates a configuration or communication error regarding Body/Chassis parameters transmitted over the J1939 data link. It often signifies that the engine is receiving unexpected or invalid data regarding body-specific functions like PTO operation or interlocks.