At a glance
What can fail
In very cold weather (near or below -20°C), ice can form in the throttle body, causing the throttle to stick in the open position. If this happens while driving, the engine may run at high speed and cause a crash.
What the fix does
Dealers will replace the PCV system and throttle body to prevent ice buildup and throttle sticking.
Summarized — see the official notice for exact wording, dates, and contacts.