2014 159" Diesel 52,000 miles. Wondering if anyone has ever had this happen: The DEF Low Refill Soon message appeared, but the tank is full. My mechanic (not a dealer shop) is able to imitate the sensor with the scan tool so we are pretty sure it not an electrical issue. Could the tank level sensor be fouled with crystals? Trying to avoid the 2k for a new tank. Thanks in advance.