2011 GMC Sierra HD2500 U0100 won't start or turn over

[jdd01]

I've had this truck for about 7 months.

 

6.0 gas WT trim if that makes any difference.

 

This morning it wouldn't start. Tried jumping battery. Voltage seems ok, still won't turn over. Has a new starter in it from for about 2 months.

 

I though ignition switch initially so I replaced it, still the same. Hooked the code reader up to it and got u0100

 

No communication with ECM/PCM

 

I checked all visible wiring under the dash, behind pedals, under body, nothing loose, damaged or pinched visibly...

 

I need help, am I going to have to take it in? I'm not a bad mechanic but I mostly work on my tractors and older trucks, not much on computer controlled engines..

[anumber1]

Have you checked the fuses?

[jdd01]

I swapped the relays for crank/run, and starter with another relay same part number, no change. It gets power, the dash and everything lights and chimes... just no turn over. I will check fuses when I'm back at the house in a bit, but when I looked before I did see anything else related to starter...