I just bought an 07 Civic EX a little over a week ago. The first thing I always do after buying a new vehicle is install a new head unit. I did the install by plugging harnesses into the factory harness and then into the new unit. After the install my check engine light was on. My car went into limp home mode. And now I get no response at all from the accelerator. The dealer checked the APP and said its functioning correct. They said a signal is going to the ECU, but the ECU isn't sending a signal to the throttle body. (Pretty sure that's how he said it). Called crutchfield tech support, and they said other than the speed sensing wire (which isn't used in the new head unit) nothing should even come close to have effecting the ECU, throttle, or accelerator. Thoughts on what could've happened. I've been installing radios since I was 15 and never had anything happen until this.