Diagnostic apparatus and method for motor driven power-assisted steering system

摘要

In diagnostic apparatus and method for a motor-driven power-assisted steering system, an abnormality determining section detects a state in which the detected normal/reverse drive current indicates an opposite to a direction of the normal/reverse revolution drive torque and determines whether the state is in excess of a predetermined abnormality determination criterion so as to determine an occurrence in abnormality of the power-assisted steering system, the abnormality determining section comprising a sensitivity reducing section that varies a sensitivity of the abnormality determination criterion in a decrease direction as an absolute value of the detected normal/reverse drive current becomes smaller.