Electronic Spark Control System Operation

ESC knock sensor detects engine spark knock. The ESC module receives sensor information and signals the ECM to retard timing. ECM normally receives a 8-10 volt signal from the ESC module. When spark knock occurs, module turns off the circuit to the ECM. Terminal "B7" goes to 0 volts and the ECM retards timing. Sensor is mounted at rear of intake manifold. The ESC module is mounted on right side fender.