Abstract: A position sensing apparatus (10) for detecting the manually selected operating mode of an automatic transmission (14) in a motor vehicle comprising a digital position sensor (20) for providing a digital position signal and an analog position sensor (22) for providing an analog position signal. The position sensing apparatus 10 may be used to advantage in a position selection and detection system which further includes a selector (12) for selecting one of a plurality of predetermined selectable positions and a decoder (18) responsive to both the digital position signal and the analog position signal for determining the selected position.

Abstract: This invention tests the mechanical integrity of an evaporative purge system and fuel system by applying a vacuum to a fuel tank and measuring the extent to which this vacuum bleeds down over a time period. Included in the test method are the steps of closing the vapor management valve positioned between the engine manifold and the evaporative purge flow path of the fuel tank; waiting a predetermined period of time; and obtaining an indication of the extent to which pressure is increasing in the fuel tank due to vapor generation.