Knock Sensor: Description and Operation

The knock sensor is mounted to the engine block under the intake manifold. The sensor is used to detect engine detonation. If knock is detected, the PCM will retard the spark timing based on the signal from the knock sensor. The PCM will always try to work back to zero compensation level or not spark retard. This new type of knock sensor, flat response, is not like the resonant sensor which was tuned for the engine. The flat response sensor creates a broader signal that is filtered within the PCM.