Sportsman 450! HELP PLEASE!!!

Okay, so its been running great, and still does for the most part, its a 2006 450. btw. but i was driving the other day coming into a open field and the whole guage cluster went blank and the quad died. luckily it came back on and fired up. but the speedo was going crazy and eventually stopped working all together.. bare with me here. well i went back and checked the gopro footage and realized the speedometer was not working for the whole ride. EVERYTHING else works fine, just no speedo and i jacked all 4 wheels off the ground and hit the throttle and all wheels spin while the switch is in 2×4. is it supposed to do that??? im very confused right now. I am dropping it off at the dealers tomorrow for them to replace my ECM for the warranty, so any other input would be great! and thank you. Personally email me if you have to @ tyhochfelder@gmail.com