PO 455 code

[Mike65]

I dropped the fuel tank to replace the electric fuel pump on Jan 12th & it has run fine up to this past week when it tripped the CEL with a PO 455 code Evap system gross leak is what my scanner is telling me. My wife tells me the truck is running fine no rough idle, no stalling, or loss of power, just the CEL is on. I cleared the code & in a couple days it is back on. I had the tank down to replace the electric fuel pump, & removed the fuel filler neck to replace the fill & vent hoses. When I put the tank back up I did remember to re-hook the vent hose to the valve on the top of the fuel tank. Today I am going to pull the filler neck out & check it for any cracks or rust. Any thing else I could check?.

 

[poker4me007]

If you don't find anything wrong check your gas cap.In the past I had a gas cap give me a evap code.

 

[boominXplorer]

Check the rubber lines that go to the evap test port on the drivers side under the hood. You should see a green cap on the unit with some very dry rotted hoses going to it (common).

 

[Mike65]

Thanks for the suggestions. I swapped the gas cap on the Explorer Sport with my 2000 Ranger which uses the same cap & my wife drove it today & no CEL yet. I looked & found the EVAP test port (green cap) by the drivers side of the radiator, & tried to follow the hose but it looks like it disappears under the battery tray. I will try to get a better look tomorrow. The hose from the test port looks like a hard plastic hose not rubber unless it is so hard & dry rotted.

 

[lobo411]

It's worth replacing with a Motorcraft cap if you have a smog check coming up. Mine was leaking and I had to have it replaced at the smog check station. They put some POS generic Fram in there and I passed, but it was damn near impossible to get the thing to seat correctly after refilling. I ended up getting the OEM Motorcraft cap at Amazon for $15.

 

[Mike65]

Update: My wife has been driving her Explorer Sport for 3 days with the gas cap on it from my 2000 Ranger & the CEL has not come back on, so I am going to order her a new gas cap.

 

[Mike65]

UPDATE; On 4/4/18 I replaced the gas cap with a Motorcraft cap & she drove the truck for 3 1/2 weeks all was fine until yesterday, she was on the highway & she said the CEL came back on.

 

[koda2000]

The evap leak will have no effect on how the truck runs unless you start seeing lean codes too. A leak anywhere from filler cap, the tank to the evap canister, the canister itself and the line going all the way up to the purge solenoid located under the battery tray and then to the intake manifold could set that code. There are also several wires that go to a evap canister solenoid.

Note: If you plan on touching the hoses on the purge solenoid under the battery tray, be sure to where rubber gloves. If you don't you'll find out why this is an important tip.

 

[Mike65]

I checked the EVAP hoses to the purge solenoid & the test port hoses & they appear ok. I ran a data stream with my OTC scanner & here is what I got at idle the EVAP vapor management valve flucuated from 1.77 volts to 2.44 volts, & the EVAP canister vent valve/solenoid read 0%, & the EVAP canister purge valve/solenoid read 25%. I can not seem to find any specs of what the readings should be.

 

[lobo411]

I'm not sure if this helps, but I found it interesting to read while trying to solve my own P0455. Luckily, mine is just a once a year annoyance so I've learned to live with it, and it doesn't affect my ability to pass smog (assuming I'm not dumb enough to have it smogged with a code set!).

1999 Ford Taurus Code Po455: Service Engine Light Is on ,the Code ...

 

[ranger7ltr]

The last time I had this code I replaced the EVAP valve under the battery... The acid leaking down over the years took a toll on the valve and the hoses...I changed it and I have not had a problem with this code in years...I bought my valve from Rockauto I believe...

 

[Mike65]

Update if anyone is interested. Yesterday I dropped the gas tank in my wife's 99 Sport to check the EVAP lines due to the CEL PO 455 code. I unhooked the vent line from the gas tank & the plastic line that runs across the top of the gas tank connects to a metal line that runs to the frame & up over the rear axle where it connects to another plastic line that connects to the charcoal canisters, right at the bend where the metal line meets the frame it was rotted out & pretty much fell off after I unhooked it from the gas tank. Here are a couple pics of the 2 pieces.
Here is the piece that connects to the vent valve on top of the gas tank,

Here is the piece that runs back to the plastic line that connects to the charcoal canisters,

What I did to fix this was the only usable piece of the metal line was the 2" piece where it connects to the plastic line that goes to the charcoal canisters, so I cut that piece off & I had a 2' section of 11/32" hose (that was left over from a repair on my Ranger) that I used in place of the badly rusted metal line. Then I had a piece of 3/8" copper/nickel brake line in the garage which I used a 2" piece of that to join the rubber hose to the plastic line the runs to the vent valve on top of the gas tank. Now my wife needs to drive it for a few weeks to see if that was the only problem, but I feel confident that it is fixed since my problem started when I dropped the gas tank to replace the fuel pump. I probably tweaked the line at that time & it started not hold pressure tripping the CEL PO 455 code.

 

[boominXplorer]

Great to hear you figured it out. It definitely had to be leaking from there with all that rust so I'm sure you fixed it.

 

[poker4me007]

Yep, you should be good to go now.