I have a 2006 Ford five hundred ltd all wheel drive with 170,000 miles. Let me start with I just had my AC fixed a must have in the desert. Yesterday when I was sitting with the car running and AC on full blast when I went to move out of park into reverse my car reved rpms and went back down but would have taken off if my foot wasn't on the break. Then I backed up and went to put it in drive and it started doing that again and then she died and a wrench came up on the dash. Car started back up I turned off the AC and it has had no issues. This has happened a few times but has never stalled and gave a code. Got the code read today and it is U0401-20 invalid or missing (CAN) data from the (PCM). I have called a couple Ford dealers and no one wants to mess with it because it's more than 10 years old. Is there anything I can do myself? Or any helpful information would be great. I love my car and want to keep it on the road. I know she has some life left in her because she runs great and loves the open road. She just doesn't seem to like the AC running on full blast and sitting still.

 

Let me know if you need something else.

 

There is a problem with the ETB, electronic throttle body or the info it is sending to the PCM.