Inductive pulse sensor (Opel Vectra B)

The pulse sensor is located in the direction of travel in front on the right in the engine block, immediately behind the crankshaft belt pulley. The sensor contains a coil and a magnet. The opposite part is the sensor disk, equipped with metal teeth. Each time a tooth of the disk passes under the pulse sensor, the magnetic field of the permanent magnet changes and voltage is created in the coil. A bicycle dynamo functions in the same way. The control unit calculates the number of revolutions of the crankshaft based on the number of voltage pulses.

To determine the ignition timing, the control unit needs information about the crankshaft position. For this purpose, two teeth are missing on the perimeter of the sensor disk. If the hole with missing teeth on the disk passes through the measurement area of the pulse sensor, then for a short moment it stops sending voltage pulses. The control unit receives information about the crankshaft position by the brief absence of voltage pulses.