Was having problems with my 2004 Hummer H2. Check engine light came on and I was having trouble filling the gas tank. The mechanic replaced my evap canister and the tank filled normally the next time. The second fill up the gas kept clicking off again. I read a bunch of the posts, watched some YouTube videos and started looking at the tubes. There was one tube that ran up by the filler neck that had what looks like a filter screwed into the end. I unscrewed the "filter" and went over to the gas station. No problem filling up since I removed it! But, I wanted to replace it, so I looked online and I went to the Cadillac dealer to get a new part. Neither the parts guys or their Hummer mechanic can tell me what this part is so I can order another one.



Filter?

 

change vent solenoid and check vent tube for restrictions

 

My 2005 has the same problem and I have replaced everything except whats above the gas tank.

On mine, that filter is the breather for the rear end. Nothing fuel related.

Tim