if the connections can be reached as it sits in the vehicle, for testing purposes of a ecu swap, one could unplug the original, and plug in the replacement ecu. then if it works as intended, go through the steps needed.
lots of ifs, if the connectors can be reached, if there is room to slide the replacement ecu down there,

 

is that mean have to take the front bumper off to switch out the ecu?