Knock Sensor: Description and Operation

Knock Sensor (KS) Circuit:

NOTE: Because different models and engine applications vary in wire colors, circuit numbers, and pin numbers, the above image is a typical example. Refer to COMPUTERS AND CONTROL SYSTEMS/SCHEMATIC AND ROUTING DIAGRAMS for specific schematic applications.

PURPOSE:
The knock sensor is located in the engine block and sends a signal to the control module to retard ignition timing during a spark knock condition. When the knock sensor senses no more knocking the control module advances timing in small increments. This allows the control module to maintain maximum timing advance under various conditions.