Get someone with SDS to read your Trans .......................
Thing is this, (applies to all Cars), cheaper Code Readers only ever see a percentage of Codes in a percentage of Modules, the SDS will get to whatever the Fault is on any system on your Car, especially if there is a Limp Mode and / or a fault light on.
This is what always makes me smile when others come on a Forum or to my Workshop and say " The xyz light / message is showing, but my mate read it and says there is no fault codes" !!
This is not directed at you btw, more for anyone else reading who doesn't know that's benefit ...............
I'll say it again ................
Whatever the Car, if there is a fault light on, a fault message, or the system is in (proper*) limp mode, there will be a Fault Code ...................... It just needs the correct equipment to access it
*NOTE:- A loss of Power does not always mean "Limp Mode"
In your particular case, if your trans is refusing to shift, then yes it (TCU) is in Limp Mode.
With this Trans, common problems are "Speed Sensor" or "TOT Sensor" Faults, which means a "Conductor Plate" change, (not too bad), also worth checking the TCU is not full of Oil, a leaky Connector can cause that, you've done the Connector, but did you remove the TCU and take off the cover to see if there is Oil present ? Washing the Circuit Board and Wiring Plug with proper Circuit Cleaner usually cures that, plus the TCU will need a reset on SDS for certain Limp Modes, (it has 2 limp modes, "Soft Limp" which just requires switch off Ignition and then restart, and "Hard Limp" which needs SDS or very good Generic machine to reset).
Can also be an ABS Wheel Speed sensor on some Cars, (not sure about Pre Facelift R170), or a Solenoid Fault, maybe Shifter Fault, and after that, there may be "Ratio Errors" ..............
Ratio Error, (assuming the Oil Level is correct, (Idling in P @ 80c), usually means the Trans is slipping and so needs a strip and rebuild, or a known good used unit, which must be one with identical 722.6xx number.
If replacing a Trans, don't forget to change the Converter with it, and also back flush the Trans Oil Cooler and Pipes with solvent ............... Parrafin, or one of the proprietary Trans Flushing Aerosols
I think that's about covered it