Knock Sensor
WARNING: This page does not describe the selected car, but rather 32 other vehicles, including the 2002 Mercury Sable, 2002 Mercury Mountaineer, 2002 Mercury Grand Marquis, 2002 Mercury Cougar, and 2002 Lincoln Town Car. However, it is still accessible from the selected car via links, so may be relevant.
The Knock Sensor (KS) is a tuned accelerometer located on the engine, which converts engine vibration to an electrical signal. PCM uses this signal to determine the presence of engine knock and retards spark timing accordingly.