The Knock Sensor (KS) is used to detect the knocking of the motor. In general, this sensor has two wires, one that gives a 5 volt reference to the sensor and the other wire is a return signal that comes from the Knock Sensor (KS) to the Powertrain Control Module (PCM).
The signal cable gives information to the Power Train Control Module (PCM) when a blow occurs, in addition to indicating the seriousness of said blow. Typically, the PCM can learn the spark shock tendencies of the engine when it functions normally.
When the P0328 DTC code is established, OBD2 indicates that the voltage has exceeded 4.5 volts, but it must be taken into account that this value depends on the make and model of the vehicle.