System and method for modifying the operation of an engine comprising an engine control unit coupled to the engine, a command module coupled to the engine control unit, wherein the command module is operable to modify operating characteristics of the engine by reconfiguring the function of the engine control unit. The engine control unit further comprises software and/or firmware, and the command module reconfigures the function of the engine control unit by altering the software and/or firmware. The command module may modify the engine operation, for example, based upon environmental conditions, topographic conditions, and/or traffic conditions.