Check coolant level light on 2000 Cadillac DeVille

Check coolant level light comes on almost as soon as the car is started. The level has been checked, coolant flush was done and the light still comes on. I was told it was the sensor and the coolant tank needed to be replaced. Is this a common problem??

Asked by for the 2000 Cadillac DeVille
i put another tank on. but light still come on.what to do next. i had the tank plug check. but do not have fire going throug it. what next?
2 more answers
The low coolant sensor is in the radiator overflow/surge tank in the bottom. It may very well be the problem. The only way to know is to have someone check the paramaters of the coolant sensor with a scan tool.
I've had this problem on several general motor! I replace the tank problem solve.