Subaru 2002 Impreza Service Manual page 39

SENSORS AND SWITCHES
I
Fuel Injection (Fuel System)
F: KNOCK SENSOR
0
The knock sensor is installed on the cylinder block, and senses knocking that occurs in the en-
gine.
0
The sensor is a piezo-electric type which converts vibration resulting from knocking into electric
signals.
0
In addition to a piezo-electric element, the sensor has a weight and case as its components.
If knocking occurs in the engine, the weight in the case moves causing the piezo-electric element
to generate
a
voltage.
0
The knock sensor harness is connected to the bulkhead harness.
(2)
(1) Nut
(2) Weight
(3) Resistor
(4) Housing
(5) Piezo-electric element
B2H1998B
A: To knock sensor harness
FU-23