What causes a SPN 3704 code?

SPN 3704 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 3704 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 3704 active.

How do I fix SPN 3704?

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 3704

J1939 SPN 3704 — Body/Chassis parameter

What it means

SPN 3704 typically refers to a Body/Chassis data link or parameter mismatch, often specifically related to the PTO (Power Take Off) or Remote Throttle interlock signals communicated over the J1939 network.