2009 Polaris Sportsman 850 XP EFI EPS Service Manual, Page 67Get this manual
ELECTRONIC FUEL INJECTION ECT Sensor Replacement
12Drain coolant to level below sensorDisconnect the ECT sensor from engine harnessRemove the T-MAP sensor to allow access to the ECT sensor
IGNITION COIL
Operation Overview
The ignition coil is used to provide high voltage to fire the spark plugsWhen the ignition key is on, DC voltage is present in primary side of the ignition coil windingsDuring engine rotation, an AC pulse is created within the crankshaft position sensor for each passing tooth on the flywheelThe two-tooth gap creates an "interrupt" input signal, corresponding to specific crankshaft positionThis signal serves as reference for the control of ignition timingThe ECU then calculates the time interval between the consecutive pulses, and determines when to trigger the voltage spike that induces the voltage from the primary to the secondary coil windings to fire the spark plugs