Knock Sensor: Description and Operation

Knock Sensor:

PURPOSE
The knock sensors (2) records engine vibrations (detonation), and signals the ECM, so that correct timing configurations can be set.

OPERATION
The sensors generate 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 ECM.