Crankshaft Position Sensors
The Crankshaft Sensor measures either the crankshaft position or rotational speed depending on it's O.E. specification. Located in most cases next to the crankshaft pulley or flywheel, the sensor feeds position or speed information to the vehicles ECU.
There are two main technologies used, hall effect and inductive. The hall effect sensor varies its output voltage in response to a magnetic field. One or more magnets are located on the crankshaft pulley or flywheel as they pass they trigger the sensor which feeds the voltage variance to the ECU that in turn interprets this signal accordingly.
The inductive sensor consists of an induction loop that has electricity passed through it to create a magnetic field. When this magnetic field is interrupted by metal passing through it the amount of current passing through the loop increases. This change in current is signalled to the ECU which in turn uses this value to calculate position or speed of the rotating component.