Just purchased a 45km 2jzge to replace the stock 300+km motor in my 03 is300 have pulled motor and have both sitting side by side and now that I have all the wiring next to each other I see some differences. One long rectangular tranny sensor doesn't fit on the auto tranny and the body wires into the lights have two plugs that use to go into old ecu that don't have a home anymore. I've tried searching differences between the two and most are auto to manual swaps but I may have a manual harness and not sure what harness would be best to use... my stock harness and ecu if it would plug into motor fine or new one with new ecu and try to splice the sensors somehow 🤔

 

Use your wiring harness and all. Differences are from year or options on car.

 

I've came to that conclusion and have started wiring the old harness back to the new motor but some of the connectors are different going to try and check if old sensors can be screwed in or not
tmo