Cadillac Repair: 1997 cadillac diville, plastic jug, engine coolant

Question
last week i was driving and all of the sudden my air shut off and it said low refrig ac off, a few days later of driving with my windows down i went to autozone and bought a can of refrigerant for the ac and it said psi 999 and on the can it said seek professional help because it was in a red zone on a psi meeter that came with the can, but now today i was driving in the morning and i noticed it still had that message but it also says check coolant, is that engine coolent now that its talking about? also my car didnt overheat or blow smoke but it was a very short drive and what do you suggest i do?

Answer
It is now referring to engine coolant. Check your radiators plastic overflow jug and make sure that it is at the FULL MARK on the jug. If it is and remains on the FULL MARK and you keep getting this message, the coolant sensor in the plastic jug is most likely faulty and needs to be replaced.