GMC Repair: P0449 code on 2000 Yukon, vent valve, scan tool

Question
My 2000 Yukon (new style/4WD/5.3 engine) has had the P0449 code for about 15k miles (currently has 75k); I know what the code means; but what do I replace/repair and in what order?  Sure would be nice to clear that check engine light one and for all!
TIA,
Dan

Answer
Hi
MOST likely cause is the EVAP vent valve is plugged.
You could remove it and take top off. It has a small "filter" in it, see if it is plugged.
If not chances are the valve itself is faulty.
Commanding it on and off with a scan tool, that will tell you everything else (wires etc...) are good.
Hope this helps.
Good Luck
Pawl