Electronic Spark Control System

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 zero volts and the ECM retards timing. Sensor is mounted at rear of intake manifold. The ESC module is mounted on right side fender.