My 06 MCS popped up an SES light. I had Advance Auto read the code. P0456, small evap leak. I checked the gas cap and indeed it was on crooked. I put the cap on correctly but the light did not go away. Later, I cleaned the cap gasket and added silicone grease, still had a light. Then today, about four days and umpteen restarts later, the light goes off.

Is this normal for the the system to wait that long to turn the light off?

YD

 

My wife put the gas cap on crooked once when we first got the MINI...didn't get a SES light though, just the "Check Filler Cap" light. Turned off the car, put the cap on right, started it back up and the light was off.

 

My understanding, YD, (and I've been wrong before) is that some emissions codes take up to 7 restarts to clear. Or the cap could be leaking a little air.

 

The same code cleared after about 5-7 restarts on my MCS.

If there is a leak, the light will most likely come back.

 

Yes it is normal not just for the MINI. Best bet is to have a code reader and clear the code.
Our Honda has the same thing and also takes about 8 starts to clear the dash light. (My wife is the primary driver of the Honda and does not worry about the gas cap and dash lights )