Eng Code P0442 & P0449

[isp5190]

Our 09 Tahoe gave codes P0442 & P0449. Awhile back the 442 came up, replaced the gas cap with a GM cap from GM Part Direct. Just the other day 442 & 449 came up, reset the light and it stayed off for about a week. Any other ideas?

 

[Doubeleive]

these 3 parts are what go bad over time, it could one, two or all three, since you are getting both codes I would just do all 3. just my .02
https://www.rockauto.com/en/moreinfo.php?pk=926315&cc=1442911&jsn=974
https://www.rockauto.com/en/moreinfo.php?pk=6588792&cc=1442911&jsn=1110
https://www.rockauto.com/en/moreinfo.php?pk=438062&cc=1442911&jsn=1114

 

[swathdiver]

Our 09 Tahoe gave codes P0442 & P0449. Awhile back the 442 came up, replaced the gas cap with a GM cap from GM Part Direct. Just the other day 442 & 449 came up, reset the light and it stayed off for about a week. Any other ideas?

You can throw parts at it and maybe solve the problem or run a smoke test to pinpoint the leak. I was considering doing as Wes suggest for mine but there is still a $130 hose on top of the gas tank that can leak too. May not be the whole hose, but just a bad three cent fitting at the end, who knows. Using my Tech-2, I did determine that the leak is NOT between the vent and purge valves. Last time the code set, a code for the fuel tank pressure sensor also set, so we're getting close. Still should run a smoke test. Other priorities let me keep kicking the can down the road.