There are bulletins in post 36 and a techlink article further in with an update cover. The bulletins have diagrams of what you are looking for but if you need step by step you'll need a service manual or alldatadiy subscription for in depth detail.
That aside, I don't like ice or water causing P0299 on your car this time of year. It's possible but would be the first case of it. Underboost has many causes - loose duct at the throttle body is common. Airbox not being tight can cause it. As can problems with the turbo itself but that hasn't been common. It could even been the boost sensor. So many possibilities that need more diagnosis.
Yes I have an AllDataDIY subscription. Have yet to find details on how to get to the CAC on it.
I have to agree. This time of year does not fit. From my research the only thing that I can find to cause P0299 is ice/water build up. This is the first I have come across with the code. It is not everyday the car goes WOT either so if there is an issue, who knows how longer it could have been there. Appears this only happens with a WOT. Have any other ideas of things I can check?
History that may/may not help.
Trifecta Tune, no other mods.
Kept up to date with maintenance going by the GM schedule.
Just last month I had spark plugs changed, oil and tire rotation. Oil catch can was emptied.
No other check engine light codes or issues.