Have been trying to figure out this no bus issue. Bought superchips tuner just over a month as go and put the performance tune on and it worked great. Drove it to a friends about 15 minutes away and of course I had fun with it but when I went to leave my friends place I turned the key and it right before the engine went to start like normal and everything lit up on dash and what not it died right after. Almost like it was in theft mode. Kept trying to reset it disconnected the battery and it's like it kept flashing in and out of theft mode by itself. After about 30 minutes it finally just randomly went back to normal and it started. But on the drive back i noticed the it wasnt driving the same way back as it did there. The next day I ended up changing out the wire harness inside the dash and since then I've had this no bus issue. Truck works and drives all lights and stuff work. I've disconnect each module on the pci as recommended and cannot think of anything else to do. I did notice my dash doesnt fully light up where the fuel gauge is. What I'm about to do now is go check for breaks on the circuit board in that spot and solder back if I have to. I also nocited that there are 3 wires from the newer harness I installed that do not connect to any wires at the junction box under the steering wheel. I traced one wire to the cluster I believe and the other two I do not know where they go yet. Also I am unsure of what exact truck the newer harness came out of. I just looked at all the connectors and seen it was a match and everything did plug right up but just having those 3 extra wires I am insure where I messed up if I did at all

 

No bus generally implies something on the 5 volt bus is dragging it down. O2 sensors are famous for that trick, but, they ain't always the culprit. Start unplugging sensors on the 5 volt bus, and see if you dash comes back.

 

If it is the o2 sensors can I just unplug the fuel management harness to get 5 volts back? They all measure 1.275 volts as they have been unplugged for a while. My truck runs like absolute trash when they're not plugged in. Always have a misfire when they're all installed and plugged In. I also read that there is 2 5 volt circuits and o2 sensors arent on either list