Strangely the code does not appear on the MVS list of codes that map to volvo codes. The actual Volvo code may prove valuable in this case, since it seems you've tried the 'easy' stuff.
As you can see on the linked page the P0444 and P0445 both map to the same Volvo code. Sometimes it works the other way around with one P code mapping to more than one Volvo code. Either way, you need someone to tell you what that P code really maps to.
The same smoke machines that can be used on intake and exhaust can also be used on evap systems - maybe it's time to track down a shop that's good with their smoke tester. Or build your own.
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1998 V70 AWD->FWD Turbo 200k+
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