Subaru 2002 Impreza Service Manual page 37

SENSORS AND SWITCHES
Fuel Injection (Fuel
System)
0
As the crankshaft rotates, each tooth aligns with the crankshaft position sensor. At that time, the
magnetic flux in the sensor's coil changes since the air gap between the sensor pickup and the
sprocket changes. This change in magnetic flux induces a voltage pulse in the sensor and the
pulse is transmitted to the ECM.
NF0398
(1)
Crankshaft position sensor
(2) Crankshaft sprocket
(3) Crankshaft half rotation
FU-21