Aiming at the problems of LRV TCMS’s real-time fault detection and diagnosis, the study of real-time fault diagnosissystem based on C++ programming language was described. Current fault status information was obtained real-timely by cyclic retrievinga list of fault, and according to the fault dictionary, the fault content was find and located, which displayed through the human machineinterface (HMI) fault display interface for drivers and maintenance personnel. Actual vehicle application demonstrated the effectivenessand scalability of this approach.