Some ECU must be read through OBD connection. If you have removed these ECUs from car, you cannot directly read them on bench or boot mode.
You have to read these ECUs via OBD on bench.
How to Connect PCMTuner to Read ECU via OBD on Bench?
Follow the wiring diagram below to connect pcmtuner ecu programmer with godiag gt105 breakout box and full protocol jumper cable.