Knock Sensor: Description and Operation

ESC Wiring Diagram:

The Electronic Spark Control (ESC) system is comprised of a knock sensor, the ESC module, and the ECM. As the knock sensor detects engine knock, it sends a voltage signal to the ECM. The ECM responds by retarding the ignition timing until the knocking ceases. As detonation is reduced, the ECM advances the timing again in small increments back to the pre-programmed point for that engine speed and load.