P0455 Error Code Question

[GONO2]

I am getting a P0455 error code on my 2003 Yukon. Gas cap has been replaced and code keeps coming back. The system is holding pressure as it relieves itself when I remove the gas cap. Code does not come up unless I let the tank get under 1/2 full. If I keep the tank well above 1/2, I do not get the code.

Any suggestions?

Thanks!!!

 

[afpj]

Is it an OEM gas cap? I had similar issues with a nonOEM locking cap...switched to OEM (yeah, cost alot more) but no more CEL.

 

[04Hoe]

A code p0455 most likely means one or more of the following has happened:

* A loose or improperly affixed gas cap
* A non-conforming gas cap (i.e. not factory/original brand)
* Other leak or damaged piece in EVAP system

With a p0455, the most common repair is to:

* Remove and reinstall the gas cap, clear the codes, and drive for a day and see if the codes come back.
* Otherwise, replace the gas cap, and/or
* Inspect the EVAP system for cuts/holes in tubes/hoses (you may hear a vacuum noise or smell fuel), repair if necessary

 

[GONO2]

does anyone know the part number for the OEM gas cap?

Thanks