Check fuse for air pump. Blown. Replaced the air pump if it's in Bad shape. The air pump is only $100 (NAPA) Gotta be water in the air pump. Water gets in air pump...then rapid below freezing conditions the air pump freezes...blows fuse.....set air pump code.
There is a GM bulletin about a new intake tube for the air pump for
exactly this problem. This new intake tube should save the air pump, get the new intake pipe/valve the same time you repair or replace the air pump if it's gone bad. Check the fuse first though, good luck.