2005 GMC 6.6 NO START P0193, p0642, P0670, P1125, P2127

Customer brought in a truck for us to re-assemble. Was running when he started working on it, he was doing head gaskets and decided he didn't want to put it back together. Truck is all back together now and won't start. we bled the fuel system numerous times, no luck. Has the codes above, and they seem to be related to the 5v reference circuit. I checked the PCM and it seems to be getting power and ground but several of the 5V reference wires are not putting out voltage. The rail pressure is fixed at 26000 psi sensor plugged in or unplugged. It appears to be getting power and ground where it is supposed to. The APP sensor however, is supposed to get 3, 5V references, and there are 3 wires getting 5V, but on the wiring diagram 2 of the wires with voltage with the sensor uplugged are labeled signal wires? I am very confused and lost. Thanks

Well everyone, figured it out! The wires for the oil pressure sensor had gotten pinched behind the accessory bracket and were shorting to ground causing problems across the whole 5v circuit. Repaired and rerouted the wires and truck is all good!