I have a ‘14 5.0 with 67,000 miles. I use both E85 and 87 octane gas. I get P455 :00-64 and P455-P failure codes that indicate a leak in EVAP. When I stick the special funnel in fuel filler I get a big whoosh of air pressure out of tank. I shot gunned with replacing the valve at the intake. No help. I get 12vdc on one side of connector at the solenoid on the intake and same on other side (while connected. When not connected just 12vdc on one side. I force a ground to it and the valve operates and vacuum is present. I have NOT changed the solenoid on the carbon canister. Any ideas out there??? Thank you in advance for any help.

BTW. I get the notification to Check Fuel Filler and I use the Forscan Light on my cellphone with the OB adapter to see the codes.

 

Are you POSITIVE it was pressure being released and not vacuum causing air to flow into the tank? If so, under what condition was that observation made?

A P0455 is not consistent with the tank being pressurized (which isn't expected to happen except under very specific circumstances).

 

Thank you for the reply. I could swear I felt the air BUT, now that I think about it, I did not smell fuel fumes! So maybe what I felt was suction. I'll get some plastic wrap and cover the filler when I do it again! Please standby.

Just went out and tried determine positively but it didn't happen which leads me to this observation:

I rarely run my 35 gallon tank down past 2/3 of a tank. I keep the tank full. I get the codes and pressure at about 100-130 miles into a full tank which is about 1/4 out of the tank (3/4 full on the gauge. Somewhere I believe that at 3/4 and 1/4 tank the system pressure tests the EVAP. This may be what is happening .

BUT, if it was a vacuum I believe the fuel filler would be sucked open enough to vent the vacuum right?

 

There are a number of prerequisites for the PCM to run the EVAP test (they're all listed in the OBDII Manual) including the fuel level must be between 15% and 85%. If you always keep the tank above 2/3 tank, you'll limit the available conditions for the test to run. It's going to take 100-140 miles from a full tank for the fuel level to drop enough so that the fuel level being too high inhibits the test. Matches what you observed and reported.

No, not supposed to. The spring in the flap is supposed to be strong enough to prevent that.

In any event, follow the directions in the owner's manual to funnel hump the filler cap to clean it and see if the issue comes back.

The P0455 is set when the EVAP test is unable to bleed up tank volume after closing the vent valve and opening the purge valve. It can be caused by anything that leaks air into the supposedly sealed system, a failure of the purge valve to supply vacuum, or the fuel tank pressure sensor failing to accurately measure the vacuum (negative pressure). A fuel cap issue or a vent valve that doesn't close would be among the more common issues. Could be a disconnected or damaged vacuum hose/line or one of the connections.

 

OK. I have some more troubleshooting to do, thanks for the knowledge. I'll fill tank tomorrow and drive until I get the failure. I'll confirm with clear plastic wrap over fuel filler and emergency funnel if it's a vacuum or a pressure release. I'll clear the codes and clean with clear silicone spray plus compressed air the fuel filler mechanism.
I'll fill tank again and drive for the 100+ miles to see if I get the codes again.

Three more questions please: At the purge valve on the engine is it normal to have 12vdc constant at the plug and NO ground on the other side of plug? I assume that the system applies ground when the purge needs to open for vacuum. Is that correct?
Further, where is the Vent valve? Is that the dreaded one on top of the tank?

Thank you so much for your help.
Steve

 

No need to to keep the fuel tank re-filled. That only prolongs the interval until the test runs again. You actually want it to run as often as possible while troubleshooting so keep it between the test entry limits.

Yes. The PCM will ground (or apply a PWM signal) to the "low" side to activate the valve.

Somewhere back on the canister or between it and an open vent line. You'll have to take a peek.

That sounds like you're referring to the FTP sensor.

 

Thank you again. I just WD40'd soaked and compressed air the fuel filler using the funnel and banged it in and out a bunch. In a day or two I'll have run the tank down to 85% or less.

 

ok here’s what I got:
filled tank
drove 61 miles tank just over 3/4 full
””Check Fuel Fill Inlet message
Checked codes and got PO 457:00-A7
checked fuel fill with funnel and plastic wrap. You were right! YES ITS A VACUUM WHOOSH !
Cleared codes and restart engine. No codes.

 

Probably time for a smoke test.

 

I guess that's out of my wheelhouse of doing myself.

Thanks for all the help!