Interestingly mine is showing P0446 on a 2001 Jamboree with the 454 (2000 year Chevy model). I reset the code and it disappeared for about 400 miles and several start stop cycles. Interestingly in both cases is that it came on within 10 minutes of a morning startup.
Since it is near end of season, I'm going to wait until spring to attempt a fix where I will be doing enough driving to see if it is fixed and any "90 day guarantee parts" haven't expired.
History: '08 View, '05 Chinook, '01 Jamboree 24D, '78 Apache Popup, 81 Komfort Tlr,
84 Mazda B2000 'w canopy,
Tent from wedding shower in '96