Almost certainly lambda sensor as mentioned above. As for the 12V socket, check the fuses behind the glovebox. Can't remember number off the top of my head number 36 or 37 or 46 or 47 I think. Underside of the glovebox tells you should be 15A I think in there. I've stuck a 25A in because my bloody 12V air compressor keeps blowing them on the initial plug in.