ABNORMALITY DETERMINATION DEVICE FOR ROTATION SENSOR

Disclosed is an abnormality determination device for a rotation sensor for detecting the rotation of a crankshaft. The rotation sensor comprises a first sensor unit and a second sensor unit which output signals phase-shifted from each other, and outputs a pulse signal. When the direction of change of the output signal of the second sensor unit is a first direction, the pulse signal having a first duration is outputted. When the direction of change of the output signal of the second sensor unit is a second direction, the pulse signal having a second duration is outputted. The abnormality determination device comprises a calculation unit which calculates the time interval between the output start times of the pulse signal, and a determination unit which determines that the rotation sensor is abnormal when the difference between two time intervals calculated continuously by the calculation unit is larger than a threshold value.