Failed emissions help

[jasper]

OK, so here's the story. Noticed a high pitched whine coming from my rear passenger tire area a couple weeks ago. That went away. Two days ago i lost my gas cap (stupid) and couldn't find one at any local auto place. I was busy, so i kept driving it for the two days with the light flashing. The whine came back and with a vengeance. Figured it was a fuel pump or fuel filter problem. Went to the dealership today and bought a new gas cap for $30. Then few hours later the CEL came on and the whine went away. Emissions was due today so i went and failed? Are these two things connected? What do i fix first?

[benaudia4]

you need to find someone with a vagcom to pull your codes. If it is the proper gas cap and it is on right then that shouldnt be a problem. It might have nothing to go with the noise from the fuel pump. Could easily be the MAF sensor or some other sensor thats why you really need a vagcom

[jasper]

Code is PO455: Evaporative Emission System Leak Detected (large leak). Could that be from leaving gas cap off for two days before the test?

[skeeball]

Yes, driving around with the cap off caused you to fail emissions. Do you have a vag-com? You can monitor your readiness codes so that when you go back you don't fail a second time.

[A4TL]

if it was the gas cap it will go away after a week or so (based on number of starts and mileage and other mysterious stuff).

if you clear the codes you may even take longer (or not) depending on how well you know how to force the tests with vag-com (~90 mile freeway drive max).

so pick your poisin and get a vag-com dude.