Have a 2015 TDI. Short story. Yesterday had warning come up ad Blue waring 1000 miles. Got home added about 1/3 of 2.5 litre jug I had at house. Left today to go out of town and check engine light came on and about 20 miles later ad blue has 250 miles came on. Stopped and put 3 gallons in and got back in and light stayed on. Went about 20 miles and bought more and finished filling up. light stayed on. Rented car and went on trip. Got back to car and drove home, about 60 miles. Now shows 95 miles to not starting. check engine light still on. Had services 3000 miles ago and know I didn't burn a whole tank in 3000 miles. Any ideas to resetting?