Knock Sensor: Description and Operation

GF07.04-P-6030MAR Knock Sensor, Component Description
- refinement package
- as of model year 09

Component Identification:

Location
The LH knock sensor is located on the left and the RH knock sensor is located on the right of the cylinder crankcase.
They are protected from the effects of overheating by a heat shield (shown detached in the picture.

Task
The knock sensors detect the vibrations on the cylinder crankcase (combustion knocking) for knock control.

Knocking can also be an indication of engine damage (e.g. increased engine noise by a widened piston groove).

Function
The vibrations on the cylinder crankcase are converted by the piezo crystals in the knock sensors into electrical DC signals. These DC voltage signals are sent directly to the ME-SFI control unit (N3/10) over 2-pin shielded lines.

Component Identification:

Piezo-electric effect: An electrical voltage is generated by the mechanical force on a piezo crystal.