Genuine OEM Volkswagen Knock Sensor, part number 07C905377AQ. This sensor is designed to detect abnormal combustion vibrations (knocking or pinging) within the engine cylinders. Upon detection, it sends an electrical signal to the engine control module (ECM), allowing it to adjust ignition timing to prevent engine damage. It is usually mounted directly onto the engine block. Genuine OEM sensors provide the precise calibration and sensitivity required for optimal engine management and performance.