I bought a used one off Ebay. This may not be your problem, but here is the part number: 8691998. Searching the internet I see new ones for about $250, but you will need to have software loaded. This module is used in a number of Volvo cars of similar era - hence I assume the software may be vehicle...

Volvo specific code reader, this will require a Volvo VIDA/DICE or another unit which is designed to interpret the Volvo module level (BCM-, ECM-, DEM- as examples) error codes. Someone on the forums is probably aware of other "Volvo" code readers by name and can offer suggestions, I am on...