Hi Guys, Just wanted to tell you, Before you go crazy over this as we did. The wiring harness was the issue. as we were testing the PCM i decided to lift up the harness in the back of the motor, as I did this, the PCM we were working on showed 5 volts and when I let it down it went away, so I lifted it up again and got 5 volts back, at that moment I took a zip tie and secured it lifting it up and tieing to the back wall of the truck. Once I did this limp mode went away and now I have no issues, So the harness must have had a short or grounding out.
Glad I lifted it up when I did cause we would have never figured the problem out by just changing parts. Hope this helps. 2004 Dodge Ram 1500 5.7 Hemi 4WD