2006 S40 Cold induced performance issues

[Dougherty27]

I own a 2006 Volvo S40 T5 AWD which drives great until the weather drops below freezing.
Below freezing temps the car hesitated during acceleration and the check engine light comes on. I have taken it to a local mechanic (who specializes in european cars) and he could not diagnose the problem. Although he did pull down two code that he could not identify. Perhaps this is related to the turbo.

Any suggestions to the root cause would be much appreciated.