Knock Sensor: Description and Operation

The knock sensors bolt onto the cylinder block below the intake manifold. They are designed to detect engine vibration that is caused by detonation.

Highly sensitive anti-knock sensors can distinguish knocking conditions in individual cylinders and retard the ignition timing on the cylinders that are knocking. This anti-knock control prevents damage to the engine and allows operation on lower grade fuel, but only in emergencies. Premium grade fuel is required under normal operating conditions to ensure full power and economy, and because the anti-knock control system may not be able to prevent knocking on low grade fuels under all operating conditions.