P0455 and P0442 2007 equinox

Question

P0455 and P0442 have been coming up on my 2007 Chevy Equinox for the past 2 summers since I purchased the vehicle. I have had it smoke tested and there was no leaks found. Have changed fuel cap and replaced old o ring in the old fuel cap and still code comes up. Codes were cleared before it got cold and stayed off all winter. As soon as it got warm they came back on again. Aggravates me for whyen this does happen I can't use my electric start

Answer 1

P0455 Evaporative emission system Large leak detected

P0442 Evaporative emission system small leak detected

You got both type leaks This can only come from one source that would be the FTP (Fuel tank pressure) sensor not reporting correctly the true pressure condition of the fuel tank.