Oil deterioration detecting device

PROBLEM TO BE SOLVED: To detect abnormality in an oil deterioration detector, and to prevent the quality of a lubricating oil from being erroneously determined in the abnormality. SOLUTION: This oil deterioration detector 1 for measuring acidity and basicity of the vehicular oil using an oil deterioration sensor 10, and for detecting the oil quality based on a measured value therein is provided with a measuring circuit 50 for measuring an output from the oil deterioration sensor 10, and an abnormality detecting circuit 80 connected between the measuring circuit 50 and the sensor 10, and having a switching means 81 contacting separably in parallel with the oil deterioration sensor 10. The abnormality detecting circuit 80 is connected in parallel to the oil deterioration sensor 10 during a prescribed time using the switching means 81, in a partial period within the whole period for measuring the output by the measuring circuit 50. COPYRIGHT: (C)2004,JPO