P0455 Gross evap leak issue | Ford Explorer Forums - Serious Explorations

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P0455 Gross evap leak issue


347 V8 Limited turbo
Elite Explorer
February 18, 2009
Reaction score
City, State
Winnipeg, Manitoba
Year, Model & Trim Level
00 Limited V8
Hi Guys,

Im fighting a P0455 code. I have replaced my gas filler neck and gas cap.
This didn't fix the issue.

The code seems to come back when my gas tank is about half full every time(Im not sure if this has anything to do with it).

Unfortunately I know very little about how this evap system works, other than there is an evap canister over top of my spare tire, and a couple of hoses going to it. Id guess one of the hoses runs from the evap canister to the filler neck. No idea where the other hose goes, or where the sensor is that triggers the code.

Thoughts anyone?

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usually a cracked fuel filler neck. I'm in the same boat.

Thats what I figured also. Replaced it as I couldn't tell for sure if there was a crack somewhere. Then, to be sure, I replaced the gas cap also. still coding out.

Apparently there's some kind of a valve that opens up (Or closes) for a vacuum test. I need to figure out where that is, and the part number. As near as I can tell, its going to be a vacuum hose, or that valve. I don't even know where that vac line starts, or ends.

Way to cold to drop the spare tire and start looking. I was hoping some one would have lived this and been able to give me some info on the valve, and where that vac line goes.

More likely it is the gas tank itself. Since you have replaced the filler neck you know the filler hoses are two rubber pipes with clamps. Turn the clamps loose and twist/pull the hoses to remove from the gas tank. You will very likely find corrosion with rust holes in the tank nipples.


Thanks for the response!
Not what I wanted to see though (As you can imagine).

This code is going to be a pain in the butt. Looks like I'll be taking the rear end apart just to see whats going on (When it warms up, of course).

The one thing I really hate is climbing under vehicles.

the easiest way to remove the rubber filler and vent hoses from the tank bungs is to remove the driver's side rear tire, sit on the ground, loosen the clamps and twist/wiggle them off. you should be able to then examine the tank bungs for rust/holes. pretty easy to do, and technically your not getting under the vehicle.

the 2000's have an electrical plug on top of tank (not sure what it's for, but i think it has something to do with the vapor system) and a plastic line that goes from the tank to the canister over the spare tire. i believe there's also a hose/line that goes from the canister to the front of the truck and attaches to something (purge valve/solenoid?) located under the battery support, and then another hose goes to the engine's intake.

northern trucks very often have the problem that the bracket that holds the vapor canister to the frame of the truck completely rusts away. drop the spare and check that too.

You guys are the best!
I had dropped my tank last spring to install the high volume fuel pump, but thought I needed to drop my tank to get at the neck. Thanks for the tip!

I replaced my shocks a couple of years ago, and my evap canister bracket was starting to look rough, and needed a couple of nuts/bolts to get it back in place. Might be more difficult to do now (Or easy If nothings holding it there anymore).

At least I can have a look at that filler neck while its still cold and miserable without loosing my mind.

what ended up being the problem ? ... < same code/problem on my 2000 Explorer Sport 4.0L OHV Manual Trans.

I wish I had the answer. The code only comes on at about a half tank when its about 5 to 10 degrees below freezing.
I havn't wanted to bother fighting with it yet. I'll pull the evap canister off in the next month or so and inspect canister/hoses for cracks. Also, while its out I'll clean the sensor/filter up. There are a few threads on that around here.

Then, while at a pick n pull, Ill replace the vacuum assy that's under the hood that controls that. I might reverse these two items timing, depending on if Im already at a pick n pull and see what I need.

I looked at my gas tank filler neck, and there is no rust around it at all.

Sorry, no completion to this thread yet.