I keep getting a p0442 that started as a p0440. I changed my gas cap because the seal was a little dry so I bought a cap from auto zone. There is a bit of wetness on the seal. Could this gas cap be causing my p0442?

 

*Moving to 2nd Gen Tech* - Please choose the section that best applies to the topic you intend to post.

I doubt that the cap is the source of your problem, but is the easiest & cheapest thing to check/change first. I ended up using only the o-ring from the aftermarket cap on my '00 Bravada when I had the P0440 code, but that was to retain the tether. It ended up being the EVAP vent solenoid back by the tank.

 

A few years back I had an evap code and put on an aftermarket cap with no luck, but when I put on a cap from the dealer - problem solved.

 

swartlkk is SO right on this one! EVAP vent solonoid probably as well as a host of other issues,look at the fuel filler neck as well as all vapor return hose quality/connections! The filler necks on these are made of tin foil and fail rapidly in a high salt climate as well. If it IS the filler neck-buy new,was in a yard in DE 2 weeks ago and the approx 15 Blazers they had:all the filler necks were toast!

 

Thanks for the responses! I ordered a cap today since its cheap enough to guess and check with it. If it doesnt fix the problem im taking it in to get a smoke test done. Il keep you updated!

 

I dont know if it changes anything, but I forgot to add p0442 only seems to come on when im under half tank.