The EGR VALVE POSITION SENSOR is used to know the position of the Exhaust Gas Recirculation Valve (EGR). It has 3 lines, which are: one ground, one positive and one signal. It is the case that the positive voltage is 12 volts and in other 5 volts.
It should be noted that in sensors of this type, the positive power and ground of the ECU (Engine Control Unit) does not help to induce a transducer, but rather to make the potential difference in the signal line of the sensor.
It works in a similar way to the TPS sensor (Throttle Position Sensor), since when the throttle valve moves, so does the potentiometer when changing the resistance value. By doing this, the voltage of the ECU (Motor Control Unit) drops on the signal line.
The Engine Control Module (ECM) studies the position of the EGR valve (Exhaust Gas Recirculation), in order to make sure that the valve is performing its function correctly, and responds to your orders as appropriate the value of the sensor signal to the position that the Engine Control Unit (ECU) has ordered before.
This sensor helps determine if the EGR valve is performing its function properly, since it may be stuck or its work may be performing slowly.