Hall Effect Sensor

On Golf III and Jetta III, sensor is an integral part of distributor. On Corrado SLC and Passat, sensor is mounted on end of camshaft (near ignition coil). Sensor consists of a magnetic enclosure and integrated semi-conductor circuit. A voltage signal is generated when trigger wheel, turning at camshaft speed, interrupts magnetic field created by semi-conductor. Hall Effect sensor and engine speed/reference signals are used to identify TDC position of cylinder No. 1 for sequential fuel injection and spark knock regulation.