if there is a problem in the transmission electronics there will be codes recorded but the data plug is not being connected up properly to read them. I suspect a faulty TCM will be the answer.
at first,try to add coolant slowly to the radiator not to the reservoir,then start the car ,keep adding coolant on it ,until it is very full.u should see the radiator fan should be also running ,then that is the right tempature.drive a little bit & observe the tempature is the normal or not."""but if u have a coolang pressure tester""",u should do a pressure test & see any leak.it might somewhere in cooling sytem leak.hope it wasn't too late,it might cause head gasket burn,it will turn out a big job.