Abstract: A single sensor apparatus and method for determining engine position and engine speed is disclosed. The apparatus includes a gear rotating in synchronism with the camshaft of an internal combustion engine. The gear includes a number of equiangularly spaced teeth, and an additional tooth mechanically synchronized with top dead center position of a particular cylinder of the engine. An algorithm is disclosed for detecting the added tooth with a high reliability and accuracy. In addition, engine speed is determined by measuring the time interval required for a predetermined quantity of gear teeth to pass the sensor by detecting the pulses corresponding to the gear teeth. The resulting time interval is converted into engine speed through a known relationship between the number of teeth on the gear and their angular spacing.