[martin.smith]

My X3 emissions warning light comes on intermittently. I have just had it to the dealer who wants to book it in to do some test. This sounds an expensive option to me, anyone any idea what it could be? Secondly, I am assuming it's straightforward enough to change the rear pads but what is this "centre" thing the dealer said I would need. I want to do the work myslef and have changed pads before, just wanted to know what this "centre" is.