Knock Sensor: Description and Operation

Knock Sensor:

PURPOSE
The knock sensor's piezoelectric element detects engine detonation and converts it to a voltage signal for the Engine Control Module (ECM).

OPERATION
The Knock Sensor sends a voltage signal to the ECM during "engine knock" episodes. The ECM will retard ignition timing until engine knock is no longer detected by the Knock Sensor.

CONSTRUCTION
(C) The knock sensor, consists of a (3) housing a (4) piezoelectric crystal mounted on a (5) threaded sleeve between (6) two connector strips. One side of the assembly is fitted with a (7) damping weight and (8) spring washer secured by a (9) nut.