Developing PC-Based Automobile Diagnostic System Based on OBD System

This paper introduces automobile diagnostic technique and on-board diagnosis (OBD) system, compares and analyzes several kinds of diagnostic protocols widely used in on-board diagnostics system. As for the problems of hand-hold diagnostic devices used in the current market, a general PC automobile fault diagnostics system based on OBD system design scheme is presented in this paper. In view of the diversity of physical layer and link layer in several widely used protocols, a general protocols electrical level transfer circuit is designed and solidified software for the protocol conversion is developed. Based on PC, multifunctional diagnostic software is also developed. The performance of each module is tested on vehicles, and the results show that the communication of this system is reliable, the diagnostic result is accurate, and the performance in human-computer interaction is good, able to meet the vehicle maintenance diagnostics and new models development and testing requirements.