Here is the response I sent to a similar question from Colin:-
I had a problem with the MIL light coming on with our 2014 GDI +4. It would usually come on with gentle or long downhill driving and would usually (but not always) reset by the next day. The code stored had the same description as you have experienced. Anyway the front sensor was changed under warranty (after a long wait for a replacement) and all was well for a while. After a couple of months it came on again and although the reading was the same the dealer said it was now the other one. They changed the rear one within a few days (again under warranty) and the light has not come on again since and we have recently completed a run of a couple of thousand miles down to Provence and back.
