ELECTRIC POWER STEERING DEVICE

PROBLEM TO BE SOLVED: To provide an electric power steering device in which a memory abnormality diagnosis is restricted during a steering assistance control operation except for during the start-up time, and a memory abnormality is efficiently detected. SOLUTION: In the electric power steering device having an electronic control device that controls an electric motor generating a steering assistance force for a steering mechanism, the electronic control device includes a data storage part that stores data necessary for the execution of the steering assistance control operation for controlling the electric motor, an abnormality diagnosis part that performs abnormality diagnosis for the data storage part, and an abnormal time control unit that changes the mode of the steering assistance control operation based on the result of the diagnosis by the storage abnormality diagnosis part. The abnormality diagnosis part performs abnormality diagnosis when the electronic control device starts up and when a state change that affects the data storage part occurs. COPYRIGHT: (C)2010,JPO&INPIT