Patent ID: 8457834

Claim:
An abnormality judgment device having a first diagnosing section configured to perform a first diagnosis for judging whether a steering angle sensor is normal, the first diagnosing section periodically obtaining a steering angle from the steering angle sensor, the first diagnosing section comprising: a first change amount calculator configured to calculate an absolute difference between a currently-obtained steering angle and a previously-obtained steering angle, as a change amount; a first storage section configured to store a maximum value of the change amount which is calculable by the first change amount calculator when the steering angle sensor is normal, as a normal threshold value; a reference setting section configured to set the previously-obtained steering angle as a reference steering angle when the change amount exceeds the normal threshold value; an incrementing section configured to continue gradually incrementing the normal threshold value after the change amount exceeds the normal threshold value, for a first judgment time; a deviation comparator configured to compare an absolute deviation between the currently-obtained steering angle and the reference steering angle with the gradually-incremented normal threshold value, and to count a first counter when the absolute deviation exceeds the normal threshold value, for the first judgment time; and a first judgment section configured to judge that the steering angle sensor is abnormal when the first counter reaches a predetermined value within the first judgment time.