About 2 weeks ago the check coolant level message would show up randomly on the DIC. But the coolant level is fine. Then in the past week it remained on. I checked the connection at the tank but nothing changed. Looking at the tank I find the sensor is not replaceable other than replacing the entire tank. Without removing any hoses, I unfastened the tank from its mountings. Figuring I had nothing to lose at this point, I tapped the area of the sensor with a plastic hammer. No change. The I shook the tank vigorously hoping a contaminate would fall off the internal sensor. It has worked fine ever since, saving me the cost of a new tank. Just FYI.