The Ignition Knock (Detonation) Sensor, also known as the Knock Sensor or KS, “listens” for certain harmonic frequencies associated with engine knock or “ping” and sends a voltage signal to the Engine Control Module (ECM) when detected.
The ECM calculates proper ignition spark timing based in part on the Ignition Knock (Detonation) Sensor’s signal. A malfunctioning or inoperative Ignition Knock (Detonation) Sensor can allow engine knock or “ping” to occur for which the ECM would otherwise adjust ignition timing to eliminate. It can also cause the Check Engine Light (CEL), Service Engine Soon (SES), or Malfunction Indicator Lamp (MIL) to illuminate and can set a trouble code (P-code) in the ECM when not functioning correctly.
Not correcting a failed Ignition Knock (Detonation) Sensor condition can cause reduced fuel mileage and performance under load, increased emissions, and damage to other components. Prolonged engine knock can cause internal engine damage from the piston skirt “slapping” against the cylinder wall.