I took my 2009 F150 with 50K miles to the dealer for two recalls and ask them to check out my code P0451. They informed me I had a issue with the EVAP control system and I needed a VCM (vacuume control module) and a (canister vent valve) for a total of $866.00. I paid them the $135 diagnostic fee and walked to the parts counter and purchased both items for $220. and it took me a total of 15 minutes to replace both. I then cleared the code and two days later it came back. After reading threads about this issue I decided the next most common proble was the capless filler neck, thinking the seal or spring was defective thus causing a vacuume leak. I replaced it and I will say the new one seemed a lot stronger but then again the code came back. There are a couple more things in the system left, 1. the tank sensor, 2. the canister, and a lot of stiff tubing. I guess if I replace everything I will be back to the $866 range but I was hoping the Ford service diagnostics they were so quick to say they prided themselves in would have isolated it better then this. Any best guesses from the experts would be greatly appreciated. THanks

 

I only found a few threads on it, they seem open ended

https://www.f150online.com/forums/20...is-dealer.html
https://www.f150online.com/forums/20...what-code.html
https://www.f150online.com/forums/20...k-removal.html

 

I would have thought that would have been covered under the emissions warranty........................

 

I explored the emissions warranty and a defective part is 3/36, a failed emissions test is 8/80. Mine runs fine and even passed inspection last week between CE light resets. Hopefully somebody will have an insight on this issue.

 

Is that the gas cap code? I know our trucks have the cap less system. Just thinking I had that code on my 2001 when I left the cap off once.

 

That is correct. I replaced my filler neck with a new one which has a new seal, so not leaking there.

 

Kind of random but funny.
Just got a letter from Ford today on the wife's 09 Explorer. It says they have a known issue with the capless filler neck leaking. So they have graciously extended the warranty on it to 15/150 if it shall ever cause an evap code...

 

Not sure what state you're in and what the rules are, but here in NH a CEL on would be considered a failed emissions test. It should not matter if inspection is due or not the fact the light is on is an emissions failure.

It should not have passed between resets, as the EVAP system was probably not in ready state. Sounds like you have already emptied your pockets enough on this one, I'd push Ford to cover the rest under warranty.