On the older models the key on key off thing worked. The new models are a little different.
2010 550 xp
1. With transmission in PARK.
2. Press and release the SELECT button until the flashing check engine waring indicator appears in the display.
3. A set of two numbers will also appear in the display.
This is on page 43 of your owners manual
I can tell you it has to be a hard code to be able to retrieve...
1985 Tri-Z 250, 1986 Tri-Z-250, 2010 Sportsman 850 XP EPS, snorkeled, 2in spring spacers, 3in SLC lift, Rad relocate, Dalton clutch kit, 31 Outlaws