Impreza RS Coupe AWD F4-2.5L SOHC (1999)
Crankshaft Position Sensor: Description and Operation
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The crankshaft position sensor is installed on the oil pump, located in the front center portion of the cylinder block, to detect the crankshaft
position. It is designed so that the ECM accurately reads the number of pulses which occur when protrusions provided at the perimeter of the
crankshaft sprocket (rotating together with the crankshaft) cross the crankshaft position sensor.
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The crankshaft position sensor is a molded type which consists of a magnet, core, coil, terminals, etc.
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Crankshaft rotation causes these protrusions to cross the crankshaft position sensor so that magnetic fluxes in the coil change with the change in air
gap between the sensor pickup and the sprocket. The change in air gap induces an electromotive force which is transmitted to the ECM.
