FYI 2002 Thunderbird - small vapor leak P0456 fix

2002 Thunderbird, 40K mi - we got an intermittent P0456 code about a small vapor leak. Replacing the gas cap didn't help and a careful examination of the tank & vent line from the tank to the vapor purge value showed no problems. The fist-sized purge valve on this car looks nothing like that shown at Rockauto, Autozone, & Advance - it is much larger & stamped XW4Z-9C915-AB and sits under a plastic cover on the driver's side (the 3 trim clips holding the cover on have a center pin that is hard to see and releases the clip when pressed down ~1/4").

I suspected that a small piece of debris was prevent the purge valve from sealing entirely, so I flushed it with a WD-40 clone spray while blowing through it - and no codes since.

It appears that the purge valve could possibly be disassembled and cleaned, but old plastic makes me nervous and I'd try to line up a spare before I try that.
 
2002 Thunderbird, 40K mi - we got an intermittent P0456 code about a small vapor leak. Replacing the gas cap didn't help and a careful examination of the tank & vent line from the tank to the vapor purge value showed no problems. The fist-sized purge valve on this car looks nothing like that shown at Rockauto, Autozone, & Advance - it is much larger & stamped XW4Z-9C915-AB and sits under a plastic cover on the driver's side (the 3 trim clips holding the cover on have a center pin that is hard to see and releases the clip when pressed down ~1/4").

I suspected that a small piece of debris was prevent the purge valve from sealing entirely, so I flushed it with a WD-40 clone spray while blowing through it - and no codes since.

It appears that the purge valve could possibly be disassembled and cleaned, but old plastic makes me nervous and I'd try to line up a spare before I try that.

Good tip on finding the leak. Thanks.
 
2002 Thunderbird, 40K mi - we got an intermittent P0456 code about a small vapor leak. Replacing the gas cap didn't help and a careful examination of the tank & vent line from the tank to the vapor purge value showed no problems. The fist-sized purge valve on this car looks nothing like that shown at Rockauto, Autozone, & Advance - it is much larger & stamped XW4Z-9C915-AB and sits under a plastic cover on the driver's side (the 3 trim clips holding the cover on have a center pin that is hard to see and releases the clip when pressed down ~1/4").

I suspected that a small piece of debris was prevent the purge valve from sealing entirely, so I flushed it with a WD-40 clone spray while blowing through it - and no codes since.

It appears that the purge valve could possibly be disassembled and cleaned, but old plastic makes me nervous and I'd try to line up a spare before I try that.
Hello:
I am not adept with using forums so please understand. Recently purchased a 2002. One owner well maintained under 60,000 miles. About a week ago, engine light, P0456 code. Visual inspections and smoke test showed nothing. Will check out the purge valve. Thank you.
 
I've just had this code pop up on my 2002 model with around 70,000 never had it before. Be careful, I went to disconnect the evap purge valve and the white locking bit that holds the pipe onto the valve connector broke because its plastic and has gone brittle. I've had to use cable ties to try and hold the pipe on it now. The purge valve itself is no longer available so you have to get either the standard CP671 or the dorman 911-128, looking at the pictures the dorman one doesn't look like it will fit as the holes for the bolts are in the wrong place so possibly have to be the standard.

I have taken my valve off, blown it through, cleared the error codes and so far seems okay but if it keeps popping up I may have to replace it. I tried looking for the pipe to see if I could replace that but couldn't find it, maybe someone has the workshop book for it and will see what the part number is for it but again it may be obsolete.
 
I just got the P0456 error code on my 2005. I removed the valve and cleaned it up by blowing air through it as much as I could. As FYI, the two vapor tubes have a plastic clip that you push on and in and then wiggle the connector off. Do not try and pull the plastic clips out. Mine were a little difficult to remove and I used a large screwdriver to pry the tubes off. I did find the purge valve on Amazon and ordered a new one. $33.40. It looks identical to the one on the car.
https://www.amazon.com/gp/product/B00BIDGKRA/?tag=thunderbirdforum-20
I will post back if the cleaning helped and also when I get the new one installed to see if hat cleared the code.
 

biddle

Forum Moderator
Staff member
I just got the P0456 error code on my 2005. I removed the valve and cleaned it up by blowing air through it as much as I could. As FYI, the two vapor tubes have a plastic clip that you push on and in and then wiggle the connector off. Do not try and pull the plastic clips out. Mine were a little difficult to remove and I used a large screwdriver to pry the tubes off. I did find the purge valve on Amazon and ordered a new one. $33.40. It looks identical to the one on the car.
https://www.amazon.com/gp/product/B00BIDGKRA/?tag=thunderbirdforum-20
I will post back if the cleaning helped and also when I get the new one installed to see if hat cleared the code.
It probably only works on 2003-2005 models.
 

JW in Dixie

Well-Known Member
2002 Thunderbird, 40K mi - we got an intermittent P0456 code about a small vapor leak. Replacing the gas cap didn't help and a careful examination of the tank & vent line from the tank to the vapor purge value showed no problems. The fist-sized purge valve on this car looks nothing like that shown at Rockauto, Autozone, & Advance - it is much larger & stamped XW4Z-9C915-AB and sits under a plastic cover on the driver's side (the 3 trim clips holding the cover on have a center pin that is hard to see and releases the clip when pressed down ~1/4").

I suspected that a small piece of debris was prevent the purge valve from sealing entirely, so I flushed it with a WD-40 clone spray while blowing through it - and no codes since.

It appears that the purge valve could possibly be disassembled and cleaned, but old plastic makes me nervous and I'd try to line up a spare before I try that.
Hot-melt glue can repair some cracked plastic items. Used it to replace the tube connector I accidentally broke.
 
I am getting the P0456 evap error code on my 2003 with 112,000 miles. First step was to replace the gas cap which didn't correct the problem as I some what expected as that would be too easy. So I next replaced the purge valve deciding to just go with new one rather than try the cleaning process thinking it is 17 year old plastic so just put a new one on. Well that worked of awhile but the code is back so if I am correct the only part left is the EVAP canister which I have heard can crack. Will probably put one on myself as that isn't out of my ability, (old car who began working on them before I was old enough to drive). Just looking for any feedback from anyone else dealing with this issue.
 
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biddle

Forum Moderator
Staff member
the only part left is the canister which I have heard can crack.
I can tell you the purge valve went out on my Mustang, and then the canister went next. I actually found a shop that could do a smoke test on the EVAP system which is the only thing you can do to know for sure. Otherwise, it's just guesswork. After I replaced the canister 2 years ago, I never have had another issue with the EVAP system.
 
Thanks for the feedback. I have a shop that can do the smoke test but at this point the only thing left is the casuistry or a leak in the lines. The canisters is more likely then a leak in the line as it is also 17 year old plastic. At this point debating getting the test done, which would probably result in them replacing the canister or just putting in on myself. Your experience is reassuring that it is that old canister. Thanks again.
 
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