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I got my 2001 z06 a few months ago, and ive been plagued with a p0440 CEL. its always on startup, never while driving. several multiple hour road trips and never has it come on, but ever 3/4 startups it kicks on. havent replaced the gas cap but its always tight and i read that p0440 indicates a bigger leak than gas cap. Occasionally there is a faint scent of gas, but nothing major. anyone have a diagram of the evap system? ive got a scan tool, is there anything i can do to further diagnose the problem with that? thanks in advance.
well, even though no one replied, i figured i would post back with an update in case anyone in the future suffers this same issue. pull your drivers side engine cover off and look for a vacuum port right around the coil pack closest to the firewall. theres a connector that has a vacuum line that runs towards the front of the engine. (if you arent sure its the right one there should be a green tag that says evap emissions regulated at 1 psi or something like that.) mine had come disconnected there causing a strong unburned fuel smell through the vents and a p0440 CEL.
well, even though no one replied, i figured i would post back with an update in case anyone in the future suffers this same issue. pull your drivers side engine cover off and look for a vacuum port right around the coil pack closest to the firewall. theres a connector that has a vacuum line that runs towards the front of the engine. (if you arent sure its the right one there should be a green tag that says evap emissions regulated at 1 psi or something like that.) mine had come disconnected there causing a strong unburned fuel smell through the vents and a p0440 CEL.
THANK YOU, DBGOODWIN! Had my valve cover gaskets replaced a month ago. A few days later, P0440 showed up. I'd clear it; a few starts/days later, it was back. Faint smell of gas from time to time. I just pulled off my driver's side engine cover, and just like you said, the little plastic port nozzle connector near the firewall was missing a hose. Found the small hose laying on top of the engine. Slid it on the connector and PROBLEM SOLVED!!! If only ALL problems were this easy. :-)