Subaru 2002 Impreza Service Manual page 74

SENSORS AND SWITCHES
Fuel injection (Fuel
System)
G: KNOCK SENSOR
0
The knock sensor is installed on the cylinder block, and senses knocking that occurs in the en-
gine.
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The sensor is a piezo-electric type which converts vibration resulting from knocking into electric
signals.
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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.
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The knock sensor harness is connected to the bulkhead harness.
( 2 ) .
( 3 ) '
(1) Nut
(2) Weight
(3) Piezo-electric element
NF0391
(4) Housing
(5) Resistor
FU-24