What causes a SPN 3674 code?

SPN 3674 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 3674 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 3674 active.

How do I fix SPN 3674?

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 3674

J1939 SPN 3674 — Body/Chassis parameter

What it means

J1939 SPN 3674 indicates a configuration error or data mismatch regarding the Body/Chassis parameters communicated over the J1939 data link. It often triggers when the engine controller expects a specific signal from the body module that is missing or invalid.