Jeep Wagoneer/Commando/Cherokee 1984-1998

Knock Sensor



The knock sensor is a tuned piezoelectric crystal transducer that is located in the cylinder head. The knock sensor provides the MCU with an electrical signal that is created by vibrations that correspond to its center frequency (5550 Hz). Vibrations from engine knock (detonation) cause the crystal inside the sensor to vibrate and produce an electrical signal that is used by the MCU to selectively retard the ignition timing of any single cylinder or combination of cylinders to eliminate the knock condition.