I was thinking the same thing. So I ran the jumper wire last night as seen here
https://chevroletforum.com/forum/sil...-update-39893/

Now the transmission acts as if it is unplugged. Pressure at idle, in p/n is 175 psi, Reverse is 180 psi, And drive is 225psi.

I also have a CEL and the code p1864 for TCC Solenoid. Should I have not ran the jumper wire? Or am I finally getting somewhere? Has anyone out there ran into this issue before? Should I remove the jumper wire at the pcm and continue with dropping the pan and checking the epc solenoid or continue on the path I am on and see what is wrong with the tcc solenoid. I did not have any CEL's before the jumper wire install but I also did not have pressure. Any help would be appreciated.