Knock Sensor: Description and Operation

Electronic Spark Advance (ESA) Control System:

As an ECU input, the knock control system permits optimum control of the Electronic Spark Advance (ESA) System. With this input, the ECU is able to control timing and prevent knocking (detonation) under a wide range of engine speed and load conditions.

Two knock sensors, located one on the side of each cylinder head, detect knock and send a signal to the knock control unit. This component, located on the left side of the engine compartment adjacent to the igniter, processes the signal and sends it to the ECU. When knocking occurs, the ECU receives the signal and retards ignition timing until knock ceases.