Note. For circuit reference, see WIRING DIAGRAMS article.
Circuit Description
Knock Sensor (KS) is used to detect engine detonation. The KS is a piezoelectric element which generates an AC signal when vibrated. Normal engine operation will cause KS to generate a signal of a certain known frequency. When engine knock is present, KS frequency changes which signals the PCM to retard ignition timing. By retarding ignition timing, engine detonation detected should be reduced.
DTC will set when engine is running and KS signal detected is greater than 3.98 volts for more than 10 seconds.