Patent ID: 7835833

Claim:
An abnormality detection device of a shift position sensor having at least three shift positions, a sliding contact movable in accordance with a shift position selecting manipulation of a driver, and a plurality of position contacts outputting prescribed contact signals when coming into contact with the sliding contact, said sliding contact having a movable range, the movable range including a plurality of shift position locations corresponding respectively to said shift positions and a transition region positioned between each adjacent two of said shift position locations, said plurality of position contacts including a plurality of first position contacts each provided to include corresponding one of said shift position locations and a part of said transition region on each side thereof, and a second position contact provided corresponding to every one of said shift position locations, at least some of said plurality of first position contacts being positioned such that arrangement locations of adjacent two of said first position contacts overlap each other by a predetermined range, said shift position sensor being configured to detect that said shift position is selected, when said contact signal is output from said second position contact, based on a combination of said contact signals output from said plurality of first position contacts, said abnormality detection device comprising: an adjacent region determination unit determining whether the combination of said contact signals from every one of said first and second position contacts belongs to any of a plurality of predetermined adjacent regions set corresponding to respective ones of said plurality of shift position locations among a plurality of regions defined corresponding to the combinations of said contact signals; and an abnormality detection unit detecting a failure of said second position contact when said contact signals have changed to experience two or more different ones of said predetermined adjacent regions by passing over said shift position location during a period in which said contact signal from said second position contact is maintained in a non-output state.