Check out the connectors for sure. Maybe you'll solve the problem. But the scanner issue is fuzzy to me. Do you need a proprietary Volvo scanner? Would a proprietary scanner indicate a missing signal to the CEM?

Manufacturers are doing a tightrope act when they attempt to obstruct independent repairs of their cars. Then if you extrapolate a little,
it makes sense that they might arrange for proprietary scanners to diagnose their
systems. I wonder what support the after market service industry has for techs.
Do the scanner manufacturers claim that their scanners are as good as the factory scanners? How can they be sure with proprietary systems?

Bill