2006 chevy sierra 2500hd 6.0 p1516 and p2135

[briantmustang]

I been having this problem on and off for about 1.5 years and I have changed harness to throttlebody and soldier the connections,throttlebody twice,checked grounds,replaced tac module,replaced throttle pedal assembly,took to dealer for reprogram bullten. One day I came to work and I came to a stop and the motor shut off and it came up p2135 and I got it a few more times so I put my old pedal assembly on and took if for the reprogram and it has not came back on but still every few days I am getting the p1516 still. I have read some threads on here about the fuse box wires and adding a ground to the pcm and I have not done those yet but is there anything else besides checking the resistant in g103 and 104? I have checked the wires from the throttle all the way back to the firewall, I have talked to the local dealerships and they do not know the fix for this problem. Please any help would be appreciated!