A method of transmitting data across a J1939 network comprises communicating at least one sensor, if not a plurality of sensors or operator interface devices, related to a utility service body data mounted on a chassis across the J1939 network on unassigned PGN/SPN combinations for various uses. Furthermore, at least one controller can evaluate other J1939 data, such as transmission gear and/or engine RPM before permitting operation of at least one function of the utility service body or upfit body with at least some embodiments.