Tahoe 03 code P0455

[shadoow98]

2003 Tahoe 5.3 4x4
So I was driving and out of no were I get the check engine light, just the light. It has been about 5 days and its still there but found out that the code is P0455. I recently got to filled up the gas and wen I open the gas cap there has a loud "Hissssss" sound exactly like when you open a soda bottle and it hasn't ever done that before. The gas cap looks fine so I guess its related to the EVAP but not to sure were to start.

Were is the EVAP system and how can I test for a leak?

Would a 2004 Yukon Denali be about the same?
http://www.youtube.com/watch?v=f1RgfO0nNOk

Would this kind of test work?
http://www.youtube.com/watch?v=VmfiI1ribdM


Trouble code P0455 is related to:
1. A loose or improperly affixed gas cap

2. A non-conforming gas cap (i.e. not factory/original brand)

3. Other leak or damaged component in EVAP system

With a P0455, the most common repair is to:

Remove and reinstall the gas cap, clear the codes, and drive your Tahoe for 100-200 miles and see if the trouble codes reappear.

 

[NJ04HOE]

I had a similar issue a few years ago and the only way I found the solution was when I went to get my state inspection done. They do some kind of test where they attach the machine to the gas cap and I failed, I replaced the cap and cleared the code then went back and it passed. I haven't had that code since.

 

[tekkitan]

Thanks for the infos. I started getting this code last week. Tried a few times reseating the cap and all that then clearing the code, but it still comes back. I found an AC Delco OEM part with the same part number on eBay for $13 shipped. Figured it was worth a shot before digging any deeper.