Knock Sensor: Description and Operation

Knock Sensor:

PURPOSE
The knock sensor records engine vibrations (detonation), and signals the ECU, so that correct timing configurations can be set.

LOCATION
The sensor is mounted to the engine block, near the oil fill tube.

OPERATION
The sensor generates a signal whenever a vibration is sensed. When a knock occurs, the piezo-electric crystal (piezo element) in the sensor is compressed by the weight above it. The squeezing of the crystal, generates a low voltage signal readable by the ECU.