POST UPDATED IN September, 2020
As the name of this sensor indicates, it is used to define the position of the piston, and it does this when an explosion is needed. It is located inside the distribution.
The Top Dead Centre Piston (TDC) is very important because the Powertrain Control Module (PCM) must be informed about the position of the piston, as this information is a measurement data.
The Powertrain Control Module (PCM) has to be aware of everything that happens inside the engine, to compare it with data from other sensors and know the compression, something that will define the internal pressure of the cylinder.
The function of the Top Dead Centre Piston Sensor (TDC) is similar to that of the CKP (Crankshaft Position Sensor), unlike the latter detects the position of each cylinder, while the TDC sensor determines the position of the piston in the cylinder when it starts the vehicle.
If the signal sent by the CKP (Crankshaft Position Sensor) to the PCM (Powertrain Control Module) is not as expected, the signal sent by the TDC sensor is used by the PCM to balance the times and at the same time the PCM indicates the fault in the CKP sensor.