Hello, I am Italian and I have a smart 450. In the last days I have your same problem. When you run with the smart over 3.500/4000 rpm , the trust plus light come on and the throttle does not respond. I must turn off and then then on the car to run again. I cheked errore with a Mbstar diag and it tells me error 46 or P2046 "Load faluire in monitoring module". I checked all the suction system parts and replaced all! The turbo ,all hoses, all sensores on the engine but the problem persist. Can I have your help? Thanks a lot