Knock Sensor: Description and Operation

Knock Sensor:

The Knock Sensors, mounted in the top of the engine, are piezoelectric element tuned to resonate at the same frequency as engine knock (detonation). As the engine knocks (detonates), the piezo elements resonate at the same frequency and produces a voltage that varies according to the amplitude of the knock. This voltage is the input signal to the ECM. This signals are input to the ECM through the KNK1 and KNK2 pins.