I have an 850 turbo with 164000 miles on it. First off, the check engine lamp came on. The engine feels fine but the light is on. Upon checking of the codes I get the following...535...413...out of the A2 sockett. As I understand it the codes are 535: Turbocharger control valve signal, and 413: EGR temp sensor signal. (alldata) I reset the codes and have driven 30+ miles without a repeat but what do the codes mean? Also I have noticed a exhaust rattle type sound while letting off of the gas whilst in a turn. I put the car on a lift and grabbed the exhaust to find nothing loose or otherwise. Could this noise be my turbo going bad while "spinning down"? It only seems to happein in a residential neighborhood while making many turns from about 30 mph going down to ~15mph and then 30 mph again and again. The sound is difficult to describe but it almost sounds like a heat shield or something of that nature. God I hope it is not my turbo, I am clueless as to how many thousands it will cost me... Help, please.