Operation CHARM: Car repair manuals for everyone.
Manuals through 2025 now available!

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Knock Sensor: Description and Operation

Knock Sensor (KS) Sensor:






The knock sensor is located in the engine block. The sensor sends a signal to the ECM, by way of the Electronic Spark Control (ESC) module, to retard ignition timing during a spark knock condition. When engine detonation stops and there is no knock signal being sent to the ECM, timing is advanced in small increments. This allows the ECM to maintain maximum timing advance under various engine load conditions.