STill working on this  problem.   I could not find the little rubber tubing on the gas filler cap.   Confused on this one.   I reset the OBD11 again and ran the car for 100 miles  and two cycles.   The lights went out, stayed out for awhile.   The the check filler cap light came on and went out.   No codes displayed on the OBD11.   Next day the perform enginge maint light came on again with the check filler cap light.   OBD11 now reads P0455  (large leak). displays again.  

Anyone know how to test the fuel tank vent valve.   I cannot seen any visibale hose damage anywhere.

Thanks

Sounds like you may have pinched or twisted the little rubber tubing that comes out of the end of your gas filler cap??? That would set the light(s) off that you described. If I remember right, it will eventually reset itself.        Mini Estate

Check the vacumm lines around the valve cover.

Check the hoses to the purge valve - the vertical black plastic cylindrical object between the passenger side engine mount the supercharger plenum.

Ken

I am not sure about the MINI, but most new cars with OBD11 use a purge valve to vent the fumes from the Canister to the engine,If that is not working it may cause the problem,the canister itself may also have a canister vent shut valve.And the other thing i have seen is rats or mice eating the tasty plastic tubing that the car companys are using for everything from quick connectors to fuel line components.

Minsuki.

I have a 2003 Cooper S and recently had the perform maintenance light and loose filler cap light come on.    I replaced the gas filler cap and the LDP unit.   Reset the OBDll and ran the car for 100 miles. I was told that to reset the ECU that you had to run the car for 100 miles.   The lights are coming on again and pushing a code of P0455 (Evaporative Emission system leak detected (large leak)).   Anyone have this problem or  can lead me in the right direction to the cause of the code?   Car has 68,000 miles.