To restrain wrong determination of an abnormality detecting device by canceling abnormality determination when the wheel speed detection value of a specified wheel is substantially zero, and the wheel speed detection values of other wheels are not substantially zero, and in the case where the rotation of the specified wheel is physically restrained as compared with the rotation of other wheels.
Output signals from the respective wheel speed sensors 10-10z of wheels WFL-WRR are input through an A/D converter 12 to a processor 24 in a control device 100, and the wheel speed is detected by using a program of a ROM 16 to conduct various control. When the wheel speed of a specified wheel is decided to be abnormal, the control device 100 compares the wheel speed average of all wheels with an estimated wheel speed based on the rotating speed of an engine by operation, and determines that there is no abnormality of the wheel speed sensor when these numerical values agree or substantially agree. Thus, abnormality determination in the stack state during running on a bad road by four-wheel drive can be canceled so as to restrain wrong determination.
ISHIKAWA TOSHIMI
ISHIDA YASUTO
AISIN SEIKI
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