In this paper, a new actuator fault detection and isolation method for a four wheel independent drive electric vehicle is proposed. Also, a controller based on sliding mode control method is proposed for lateral stability of the vehicle. The proposed control method is designed in three high, medium and low levels. At the high-level, the vehicle desired dynamics such as longitudinal speed reference and yaw rate reference are determined. The medium-level is designed to achieve desired traction force and yaw moment based on the sliding mode control. At the low-level, by defining and optimally minimizing a cost function, proper force or torque signals are determined to apply to the wheels. Moreover, this paper also presents a new method for actuator fault detection and isolation in electric vehicles. The proposed fault detection method uses comparison of sliding ratio of different wheels. Using the proposed method, value of the actuator fault and its position are accurately estimated and diagnosed. Then, the proposed controller is modified and adapted to new conditions using the fault identification results. Finally, the validity of proposed controller is confirmed by the conducted simulations in MATLAB and CARSIM environments
