Would anyone have any idea what would cause the amber hill descent light and the traction control warning light to come on at random after driving a few miles in my 2002 TD4.They go off again if you stop and pull away again the only clue is if you go round a sweeping left hand bend there is a squeel from the front left wheel. I have checked the pads and cant see anything wrong. The lights are not flashing but stay on Help !