P0445 and P0449 code
 

I have a 06 z71 with 140k on it. A few days ago It started flashing "check gas cap" then check engine light came on. It has P0445 and P0449. I cleared them last night and light came back on within a few miles. Haven't really done any research or troubleshooting at all yet. Thought I'd see if you guys could point me in the right direction. Thanks!