I found this in the Polaris ATV forums, from a fellow in NY with a 2011 X2 Sportsman 550 w EPS:
"Mine does this from time to time, it has to do with the vehicle speed sensor being a bit to sensitive. This almost always happens when shifting from reverse to forward ot vice versa/ When you shift gears, the shift fork in the transmission engages a gear, the gears may "jump" as they mesh together. The teeth on the gear that the speed sensor reads off of sees 2 gear teeth go by really quickly and the ECM interprets this as high vehicle speed and the CEL comes on.
There are a few threads on this, there is no real fix for it. Mine has done it 7 or 8 times in 1600 miles. I spoke to my dealer about it and he didn't have much to say other than to replace the vehicle speed sensor. A new sensor made no difference in mine. It doesn't happen often enough for me to worry about it, so I just ride it lol. The code always goes inactive and CEL always goes off on the next shift."
And this in the PRC Ranger Club Forum from a fellow with a 2014 900XP LE White Lightning Ranger :
Took the Ranger to the dealer about the code. When hooked up to their machine they saw the saved code but couldn't do anything about it. Ranger was running perfect. They pulled the sensor and checked it another way and nothing. Last time I rode the code came up and I let the dealer know and document it but was told if its running fine don't bother bringing it in! This is just an fyi post!
Sounds like we have a few Polaris owners experiencing this problem across different models, and are having the sensors replaced. But do we know that it is the cure, or is it what the dealers are doing in hopes that will fix it. Sometimes manufacturers leave the dealers hanging until they determine what is actually happening. It's always possible a certain component was made and didn't quite meet the standards required.
I applaud Polaris dealers for doing all they can, taking care of their customers, and diligently working to find the fix, sometimes without direction from the manufacturer. All warranty work does not pay off! Manufacturers don't always pay their warranty claims, especially if you have the same issue more than one time. And sometimes it costs more to file the claim than it does to just fix the customer's problem and eat the cost of fixing it.
Here's an example of a manufacturer hiding an issue, and making their customers pay to fix their problem unless they are the "squeaky wheel"!
My boss had an engine failure in his top of the line '07 GMC Yukon Denali @ 67,000 miles. We found a "dealer only" (not public knowledge) tech bulletin that stated that if trouble codes were these certain numbers, the engine ran rough and had a miss, then after removing the valve cover, you should find one or more valve springs laying loose on the head. If so, replace the engine!!! This was the GM Vortec 6200 engine. He had to press the regional GM service manager to get any help with the cost, as it was a private bulletin. Apparently, they had some valves that were not properly heat treated, and they could break and fail at any time. GM was apparently hoping that the majority of them would get out of the GM warranty period, and then they could redact the bulletin and charge customers for their own defective parts problem. The valves may have been sourced from China, or who knows where. Things can happen anywhere, but to try to cover it up or hide it, not recall the problem, that's the bad thing for the general public.
If the codes come back in the machines with the new sensors installed, I would be inclined to lean towards the explanation about the false speed being picked up in the computer from the gearing "jumping" and throwing the code. Polaris may be trying to replicate the error which throws the code with equipment connected to determine the actual malfunction. I am just glad that at least the code clears out and the vehicle goes back to operating properly until it gets thrown again. That's different than what is in our autos and trucks. That code stays in the computer until a scan tool clears it out...and the vehicle may or may not run properly. I would hate to pay a tow bill or push a dead ATV out of the woods!
We'll see what transpires.