Knock Sensor (KS)
Knock Sensor (KS)

The knock sensor is used to detect engine detonation (spark knock). As a result, a voltage sent to the PCM will retard spark timing. The KS is a piezoelectric accelerometer with the sensor designed to resonate at approximately the same frequency as the engine knock frequency. The KS uses the resonant frequency to mechanically amplify the vibrations. This method allows relatively large signals to be achieved without electrical amplification and with small package size.

knock sensor diagram