That is an obscene amount of work to get to something so silly. I'd have cut a panel out of the boot before dropping the whole rear end of the car. hahaThis is a long read but worth it, if it helps.
It will [eventually] get into the details of potential repair options for the PB module.
Given the amount of work involved, prior to removing a suspect PBM I advise spending a couple of bucks having someone with SDD determine whether the PBM can be communicated with as there is currently no repair available for a fried circuit board.