I was driving in EV mode yesterday and I heard a beep and the emissions light came on. I havent had the ICE come on in over 100 miles so not sure why. I went home and disconnected the negative lead from the battery for 15 minutes (very easy with one bolt). I trickle charged the 12v battery after I hooked up the neg lead back up. Cleared the error code and everything seems to be back to normal. The manual states that unplugging the battery resets the emission codes so I thought I would try it. If it pops up again I WILL immediately take it to the dealership. Just thought I would share.