I would buy a replacement BCU
same year, same transmission
roadster

fast and easy swap
under $85 on ebay
roadster
2005
Automatic
currently listed

https://www.ebay.ca/itm/113157736039...mis&media=COPY

These units are aging. If the DRB sees it…
It’s easy to swap and it’s worth a shot

worst case you have a spare BCU