I recently coded p0715 turbine/speed sensor, I did some research. Bought a new connector plate and 6 quarts of trans fluid. After replacing and cleaning the pan and everything involved we replaced the connector plate and the fluid to the appropriate level. I am still stuck in limp mode and I still code p0715. Today I drove the car to a repair shop to see if they would be able to clear the code more in depth than I was able to with "turbo" the android app. They "cleared" it (*probably no less in-depth than I*) but when I started the car the code came back on. What do you guys think I should do? My dads losing faith in the car and i'd rather not sell it.
Could it possibly be:
I read some things about the TCM being the issue with limp mode and I believe my dad checked it out. He took one of the plugs and unplugged it for about 30 seconds but what I had read was to leave it unplugged over night. If I do so, and it clears the memory, How would I retrain the TCM unit?

The reason I think this would work, too my understanding, although we replaced the connector plate the TCM unit still believes it to be broken or faulty. If im correct (unlikely) the unit is coding p0715 and keeping the car in LIMP mode to protect itsself from damage. And until I tell the car its not damaged/ safe to shift, it will stay in limp mode. Mainly I need to know how to retrain the TCM because I've never done this and I believe its the last thing I've left to try as a solution.