Help with evap codes

[2Fish]

A few weeks ago the check fuel cap light came on in my 03 XLS, 2 days later the SES light came on. I had the codes read and it returned P0455 and P0457. I purchased a new fuel cap and had the codes cleared. The lights stayed off for about a week. Then the SES light with code P0455 followed a few days later with the fuel cap light. Currently reading P0455 and P0457.

I have searched this forum and have deduced that this could be a difficult solve. I have checked for vac. Leaks and such with no success. I have not been able to locate the charcoal canister (former GM person and not familiar with Ford location) as yet.

The car does have a whistle in the engine bay in temps below 20 degrees. I am beginning to believe an intake gasket for the whistle, could that cause these codes?

Any help in diagnosing these codes would be appreciated.

It is a 2003 XLS 4.0 and 113k on the clock.

 

[Tbars4]

...I am thinking maybe your new fuel cap can be the problem...:scratch:...Where did you get it and what brand is it???

...This thread sounds similar to this one and it has the P0455 code in it..
http://www.explorerforum.com/forums/showthread.php?t=244396&highlight=p0455

...This thread may be more helpful though...
http://www.explorerforum.com/forums/showthread.php?t=157076&highlight=p0457

 

[2Fish]

Thanks for your reply, I had read the second thread before posting. I am not having any problems fueling and didn't want to replace the fuel neck until certain. It's $290

I went with the $24 OEM cap.

 

[Tbars4]

...Oem Replacements are not always as good as the original...It is common for the older Explorers and Rangers to crack their fuel filler hoses also...

 

[2Fish]

After replacing the gas cap again, this time from the dealer, the lights come back on 2 days after clearing codes. Now it appears the gas cap loosens after a couple of days. After 2 days of driving (roughly 225 miles) I can remove the gas cap without turning it.

After noticing this, I have cleared the codes and re-tightened the gas cap each morning. Again the lights come on after 2 days. Is there a possible pressure backup in the tank? If so, what are some possible scenarios.

 

[Tbars4]

...Have you checked your cannister and other items mentioned in the links I previously posted here???..:scratch:

 

[2Fish]

As mentioned earlier, I haven't been able to locate the canister. The linked thread say to the side of the spare but I am unable to locate it (my first Ford). Could you offer a location description or pic?

 

[Tbars4]

...I am not familiar with the 03 model but, up to 01 you would remove the spare to see it...

...This link should give you a little more insight...
http://www.ford-trucks.com/forums/107162-evap-on-99-explorer.html

...This thread leads me to believe it is above the tank on a 2002 and newer model..
http://www.automotiveforums.com/t941005-2004_ford_explorer_won_t_accept_gas____.html

 

[rrgone]

After replacing the gas cap again, this time from the dealer, the lights come back on 2 days after clearing codes. Now it appears the gas cap loosens after a couple of days. After 2 days of driving (roughly 225 miles) I can remove the gas cap without turning it.

After noticing this, I have cleared the codes and re-tightened the gas cap each morning. Again the lights come on after 2 days. Is there a possible pressure backup in the tank? If so, what are some possible scenarios.

I think it's probably significant that your gas cap can loosen by itself. Have you looked very carefully at the 'threaded' area of the filler neck for a crack or some kind of defect? I would think that the loose cap can set both of those codes. Other than that, here's a bunch of stuff that may or may not help you.

TSB 03-20-3:
http://www.stangnet.com/images/stories/docs/sn95_TSBs/03-20-03.pdf

In the following two pics the 4 column headings are:
'DTC' - 'Description' - 'Possible Causes' - 'Diadnostic Aides'

Here is the illustration from the 2003 WSM for where these emissions parts are located. As you can see there are 2 evap canisters and they are both located on top of the gas tank requiring dropping the tank for access. The vent valve and tank pressure sensor are also on top of the tank. You can get at the purge valve for inspection w/o dropping the tank though.

Let us know what you find out. Good luck.