Automotive electronic engine control systems require complex interactive software designs which must provide appropriate responses to a variety of engine conditions. Software design verification will help achieve a high level of confidence in the released product. Several approaches to software design verification are discussed. Each technique provides an additional degree of confidence with a corresponding level of effort. Primary attention is given to the time based stimulus generation, the real time performance measurements, time based tolerance generation, and data reduction of a real time software design verification test system. A recommendation for future software design verification system capabilities is made.