Knock Sensor(s)

Knock sensor(s) works like a microphone to "listen" for spark knock (detonation). When detonation occurs, ignition timing is retarded until knock is eliminated.

On Corrado SLC and Passat, 2 knock sensors are mounted on side of engine block. Knock sensor I monitors cylinders No. 1, 3 and 5. Knock sensor II monitors cylinders No. 2, 4 and 6.