why does the check eng. light stays on all of the time on 2000 Cadillac DeVille

does it have anything to do with losing coolage

Asked by for the 2000 Cadillac DeVille
You need to have your check engine light codes read to see what systems have a fault. If you are also loosing coolant, you could be at serious risk of damaging your engine. Once the technician knows what system has a fault, they can determine the exact cause and recommend a repair.