Yep, thats it, the ef signal between the PCM and the IDM. So it can be a bad IDM, or a bad PCM, or a bad wire/lose connection..Rustler, sounds like you have been there before.
Customers truck just worked on by a shop, area-parking brake. So, I put 2 and 2 together and believe it is related to work on truck. Guess I have to dig deeper, and AGAIN fix others work.. THANKS GUYS..
P.S. pulled chip to see if that was it.