CHECK ENGINE light - code P0440

[Nerfzooka]

Well it could be something simple. My check engine light came on yesterday, this morning it showed the P440 code. We just had to clean some corrosion off the gas fill tube and undo the battery for a minute to reset it. Drove it around all afternoon and the CL light stays off.

[johnnyapollo]

I've been having this code pop-up for the past 6 weeks or so - thought it was the gas cap and first tried cleaning the cap/fill tube, tightening some extra clicks, then clearing the code - which would work for a week or two, then the CEL would come back on. Next I removed and cleaned some of the emission parts (needed to preform that maintenance anyway) and reset. Finally broke down and bought an aftermarket Lucas cap to try it out and reset - lasted for a day then came back on. I'm not sure what to try next.

I'm thinking it's the evap cannister but wanted to check first to see if anyone else went through the checklist and get some opinions.

-- John