Electronic control system of the engine is composed of various sensors and actuators, This paper is concerned with fault analysis for the stable operation of it. We suggest the technology that can systematically and reliably analyze fault causes of sensors and actuators by using the fault generating program. In results, we can acquire the systematic road map of occurring faults as well as the valuable information related to the operations of sensors and actuators. These results should be very useful to get the classification of fault causes, develop an electronic control system of engine, and review control strategies of it.