My S-Max is just over a year old and the exhaust started making a noise yesterday. Took it to Kwik-fit and they looked at it and said that the front sensor had corroded and come away from the exhaust. It should thread into the exhaust under the engine but the metal around the thread has corroded away. Also there were no warning sensors flashing on the dashboard. They said it should be covered by warranty and local garage wants £60 to look at it. Do you think this is a warranty issue as I don't see why I should be paying out loads for a new exhaust for a 1 year old car.