Okay, well I got a lot more net time than I expected today, so I've written my auto story and read yours.
So your power light stays on after you change gears and press the power button on and off in the right sequence?
If so, you need to get a copy of page 41 and 42 of the AT section of Nissan's GQ workshop manual, it clearly explains how to test each of these components. No guesswork, just checking voltages at the TCU with a multimeter. It's a process of elimination.
I found this very tedious with our auto, but it was what led to fixing it.
So in less than a week this should arrive?

