WE have a new to us 06 with 40k on it and last week y wife put 87 octane in it by accident. about 4 days later the SES and CGC lights both came on. the SES light has stayed on for a week and the CGC light comes and goes. I have since drained the gas and refilled with 97 octane.
Question is do the 2 lights work together? The oil was changed at the dealer before we bought it and maybe the SES light just needs a reset. But what about the CGC light?

 

New vehicles pressurized the gas tank to check for leaks. Most cars just toss a SES light, but mini has a specific one for the cap to save a trip to the station. If your cap is broken or an incorrect one, it could be all you need. Otherwise there may be a leak (it can be an air leak...for environmental issues they don't want fumes escaping) that you have to find. The cap must be tight or you will (and are supposed to) get a light. Buying a new one is probably the best first step if it won't work, though a radiator cap testor often has a gas cap adapter to test them too.

Scanning the codes may help figure it out.

 

Make sure the cap is on tight. Those cap lights usually go off within a day or two. If it stays on longer, buy a new cap. As far as the SES light being on, 9 times out of ten it was because of the 87 octane gas, but don't worry about that. The computers will control timing so you won't do any damage. Performance will suffer though. Next time this happens, you don't have to drain the tank, just put a bottle of octane booster into the tank. Find out what the code is for the SES and go from there. In any case, sounds like you are okay.

 

I'm having a similar prob with my 2003 mini S. My SES light comes on and off as well as my check filter cap light... Any ideas as to what it could be??