I bought an 02 avalanche a few months ago and i've been chasing issues with it..

It started with some dash gauges not working and the DTC/OBDII Port not working. Unplugged the TCCM and got the gauges back and the DTC port working.
Now i have codes u1301, p0134 and, p1860. I did have p1626, but a relearn seemed to have cleared that up; but the security light still flashes when the truck is off. I have a new pwm and tcc solenoid and filter, but i don't want to slap them in there and still have p1860 because of the communications error.

I saw another user comment about how much voltage you have at Pin 2/PPL on the OBDII connector and i only have .22-.56v with the key on, engine not running.

I feel like it's another module issue. I'm going to crawl under the truck and unplug the abs to see if the u1301 will go away, but i'm hoping someone can help me diagnose without having to spend more hours tracing down each circuit

 

Update:
Crawled under the truck unplugged the abs module under driver door and no more u1031.. replaced by u1041 (loss of ebcm communication) which is expected.

Looks like i'll need to replace both modules and inspect the wiring.

 

Horn wires behind the airbag in the steering wheel, what is this wire called and more specifically what is supposed to hold it in place. Horn works when I push it into position and hold it there, won't latch/clip to anything and doesn't work unless I'm holding it.