ABS system troubles

[roadrage201]

I've got a 2012 Silverado 1500 Z71 and I'm disgusted with it. The trouble started when my 4wd would not go into 4 Auto and would barely shift into 2hi and 2lo. I received a "service four wheel drive" display. My local shop pulled the code that basically said the front differential actuator was faulty. I cant remember the exact code.. anyway, I changed the actuator (very easy fix...I thought). The problem persisted. Now, I'm not sure what prompted me to do this, but I pulled the encoder motor from the transfer case. As I was doing  this, the motor bumped into the t case and arced. This is when the lights on the 4wd knob went out. So, after that I bought a new encoder motor. I also replaced the TREC fuse. It had popped, I'm guessing, when the arc occurred. Now, after all this, not ONLY is my 4wd auto STILL not working, but my dash is lit up with the same "service 4wd system", but also the "service trailer brake system", brake light and traction control light. I got the codes read again, and it is displaying U0121, Cannot communicate with ABS controller. I have inspected the ABS controller connection for corrosion and loose fitting as well as checked ALL fuses. I tested the grounds and hot wire pins. I also tested and cleaned the chassis ground connection on the frame. All good. I suspect that the OBD2 needs to be reset but I'm not sure.  Anyone have any suggestions?