Abstract:The article designed a fault diagnosis algorithm based on analytic model to achieve the selfdiagnosis function of sensors signals. Firstly the article established the fundamental frame, Then two fault diagnosis algorithms were designed based on parity equations and observer. Parity equation algorithm was designed by linear vehicle model and kinematic equations which show the relations among the different key sensors signals of vehicle stability control system, and was used for them to diagnose each other. Observer algorithm was designed by nonlinear vehicle model to obtain fault information by Dragon Berger observer. Considering sensitivity and false warning rate, the fusion of the two algorithms were proposed to improve diagnosis effect, and the diagnosis rules were also reset. Finally, the fault diagnosis algorithm was testified through several kinds of onroad tests with different working conditions. The results showed that the algorithm can provide accurate different types fault information of different sensors as well as the fault degree.