Owner manual says "The exhaust emissions have deteriorated. Have the vehicle checked as soon as possible." Is this a serious engine problem or one of those emissions issues that really doesn't affect the engine?

 

Can be anything -- How is the car running/performing?

 

Car seems to be running normally. Just filled up with gas.

 

Can be something simple like a loose gas cap.

 

I have this same problem. I was driving back to Tulsa from Oklahoma City at 80mph and the light came one. The car seems to be driving normally. Has anyone had experience with going to Autozone, O'Reilly's, etc. to have them plug a diags appliance into the OBD port to see what the code is?

 

I received a letter from MINI USA in August 2009 that gave notice about a possible oxygen sensor failure that would cause the OP's described symptoms. MINI USA stated in their letter that they were extending the emissions warranty for the oxygen sensor to 10 years or 100,000 miles for 2004 through 2006 models. If appicable, it might be worth having a MINI repair technician look at it?