Knock Sensor: Description and Operation

Knock Sensor:

PURPOSE
Knock sensor detects engine knock and sends a signal to the PCME. When knocking occurs, PCME retards ignition timing until knock ceases.

LOCATION
Beneath intake manifold, between cylinder banks.

OPERATION
When sensor crystal structure is distorted by a knock of sufficient intensity and frequency, a small voltage potential is created. Voltage signal is interpreted by PCME as engine knock and timing is retarded as needed until knock is eliminated.

CONSTRUCTION
Knock sensor contains a crystal element with electrodes attached to opposing sides.