I have a 2014 Leisure travel van with the same MB Sprinter engine and also got my first low Def fluid warning around 4000 miles or so. I added fluid and no problem. Around 5000 Miles a check engine light came on which was related to the emissions system. A MB DEALER checked it out and reported some kind of sensor needed replacing. It was well under warranty and I'm keeping my fingers crossed! If the government in their infinite wisdom didn't require all that******on the engines we'd get better mileage and have a lot more power! BTW, I add DEF fluid from Walmart, and appreciate the tip to keep the reservoir topped off! Might save some grief later?
