ABNORMALITY DETERMINATION DEVICE FOR ROTATION SENSOR

Provided is an abnormality determination device for a rotation sensor for detecting the rotation of a crankshaft. The rotation sensor comprises a sub sensor and a main sensor each of which outputs a pulsed signal every time the rotation body rotates by a predetermined angle. The rotation sensor is configured to, when the condition that the output signal of the sub sensor has a predetermined value and the output signal of the main sensor has changed is met, output a pulse signal in a different output form according to the direction of change of the output signal of the main sensor when the condition is met. The abnormality determination device is provided with an electronic controller which determines that the rotation sensor is abnormal on the basis of the fact that the output form of one pulse signal and the output form of the other pulse signal of two pulse signals outputted continuously from the rotation sensor within a determination period in which the crankshaft rotates in only a predetermined direction are different.