Apparatus are provided for PTO related engine control having improved failure modes and communication with PCM or ECM independent of input architecture. The apparatus includes a control module for a vehicle powertrain having an input circuit receiving signals corresponding to a four-bit code, and a processor connected to the input circuit and outputting a control signal corresponding to one of a plurality of four-bit coded engine control states. The engine control states are coded such that potential errors in communication between the control module and powertrain, and their resulting effects on powertrain operation, are minimized. For example, a single bit change during communication does not result in a transition from one engine control state to another engine control state.