Detonation (Knock) Sensor

The detonation sensor is a piezoelectric crystal capable of converting vibration caused by engine knocking (detonation) into voltage signals. The intensity of the voltage signal is proportional to the severity of the knocking. The ECU modifies ignition timing to reduce detonation. Detonation is not a result of normal engine operation and should not be present on a properly functioning vehicle using quality fuel. Two detonations sensors (one for each side of engine) are used.