'97 deville service engine soon

just bought '97 deville, runs great but service engine light came on after about 1 month. Nothing seems to be wrong. Just low on ac coolant. Any ideas.

You will have to check the computers stored error codes. There is a way to do it manually, or go to a place like Autozone where they can check it for you with a scan tool.

thank you very much. it is very appreciated.