The pump could have a jammed relief valve also.. if it got some junk in it it can jam up like that. If it isn't that front cam plate, the other side of that oil gallery is plugged by the rear cover, so it could be that as well. I would recommend replacing the oil bayonet plug and rear main seal while you have the rear cover off if you make it that far.
I had the transmission go out on my 2011 Suburban over the 4th of July weekend. It was also getting low oil pressure and throwing a code. I'm pretty sure my issue was the sending unit and screen, but I also had a nasty leak from the back of the motor. So while I have the trans out, I pulled the rear cover last night and have changed the bayonet plug, resealed the bottom of the cover(that's where the majority of the leak was coming from), installed a new cover gasket, and will put a new main seal in while I'm at it. I also had a very minor weeping leak coming from the outer bottom of the main seal(which I thought was an odd place for it to leak). Hopefully tonight I can finish the rear cover replacement and start her up to check the oil pressure and do a few other engine related things while I'm waiting on two replacement molded pistons to come in for the transmission rebuild.