Why does an accelerator pedal stop working after replacing the throttle control? on 2007 Dodge Caliber

In winter 2013 my car Dodge Caliber sxt 2007 didn't start. It was diagnosed that that there was a problem with a fuse box. The fuse box was replaced. While being replaced the throttle control went wrong. Afterwards the later was also replaced. For 5 minutes the car had worked perfectly but then the accelerator pedal stopped reacting (working). So my mechanic is puzzled and can't diagnose the problem. Could you help me?

Asked by for the 2007 Dodge Caliber