Detonation (Knock) Sensor

Detonation sensor is a piezoelectric crystal capable of converting vibration caused by engine knock (detonation) into voltage signals. Intensity of voltage signal is proportional to severity of knock. 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. Q45 uses 2 detonation sensors (one for each side of engine).