Hi all,

Engine light came on yesterday. I have an Actron pocket scanner that tells me the code is P0456. {EMISSIONS/EVAP PRESUURE LEAK} . I've been reading that its very difficult to diagnose the actual cause with this code. Where do I even begin and what parts should i check?

 

Gas Cap would be my first guess...

 

Hi Techep, it's actually one of those capless gas tanks. I forgot to mention, my vehicle is a 2013 F-150 {flexfuel}

 

check the flapper... may not be closing all the way.

 

I did check the gas door/flapper, gasket looks good, nothing is bent.

 

I think techrep meant the little door inside the tube, not the outside door. I don't know how to say this without sounding like a porno. Use the funnel to work that little door a bunch, WD-40 may help.

 

so your saying the small door where the actual tip of the gas pump goes into can get stuck or something?

 

Yes... like stated use your funnel...

 

You can get the Locking Fuel cap and see if it stops it and if that doesn't fix it next thing on the list is the Purge Valve. Unplug a wire connection, a plastic hose and 2 5/16 (8mm) bolts and it is fixed.

 

That'd be the next thing I check. If you need a new one you should be able to find it for about $30, maybe even cheaper if you get a good discount somewhere.