Just another 01

So I have a launch scan tool, why doesn’t any of my transmission data read? It has a place for a reading but there is lousy a line there, no reading. Also my overdrive button on my column shifter doesn’t work. I’m driving the truck right now and it shifts fine. I ordered the OBD2. It will be here tomorrow.

So, lets just say there is no message and or no pulse, then what?

Where do I buy one of those scan tools? Does it have to be that particular one? The pcm i just got back yestereday. it supposed to be good. set to my vin

the pcm is brand new. the codes are 920,921,999. I also put a new APPS

I need some help. I have no gauges on my dash except for my tack that works. I have put a new transmission wiring repair kit, I have cleaned all the terminals, I have checked all the wires that I can see and I put a new pcm on it. it will crank and drive but i have to start off in first and to get it started going then I can put it in drive and it will shift on its own. Im about ready to drive it off a cliff. (lol) any suggestions will be much appreciated and at this point I'm willing to try anything.