Transmission range sensors record the transmission speed. This information is required by the control unit to regulate the shifting pressure when shifting gears and to decide which gear needs to be engaged at which point.
There are two types of transmission range sensor design: Hall generators and inductive sensors.
The rotation of the ring gear changes the magnetic field, which, in turn, changes the voltage in the transmission range sensor. These voltage signals are forwarded to the control unit by the transmission range sensor.