PO 449 would be related to the Evap system, vent solinoid control curcuit.
This may be a soft code (Symptom but not the problem) not a hard code (one of the actual problems). One should properly diagnose this at a qualified repair facility to get a more accurate dianoses.
If you need this diagnosed properly you can call one of our four stores @
1) Willowbrook (281) 890-9400 3) The Woodlands (281) 465-9410
2) Champions (281) 370-7900 4) Cypress (281) 304-7833