2012 Sportsman 400/500 and EFI Tractor Service Manual 9923412, Page 385Get this manual
ELECTRICAL IGNITION SYSTEM
Overview
The Sportsman has incorporated into it's design DC CDI ignition systemThe DC ignition system relies on battery power for ignitionEFIInstead of generating DC voltage via flywheel magnetic induction, 12 Vdc current is supplied from the IgnitionFuel Pump Relay to the Ignition coilAt the ECU, small AC signal from the CPS helps the ECU pre-determine Top Dead Center (TDC), which in turn signals the ECU to release the electrical charge collapsing the coil field for ignition (based on the ECU timing map)CDI- 12 volt DC current is supplied directly from the battery to the CDIAt the CDI, DC current is supplied to the coil for the initial ignition chargeA small AC signal from the stator pulse coil triggers the CDI to fire the coilDCignition systems have the ability to ignite with as little as volts of powerSome of the advantages of DC ignition are: Stronger, more consistent spark at low rpm for better performance Easier starts Fault detection by the ECU (EFI)