I'm getting a P0441 code and the Trac off light. Replacing the gas cap to no avail. Cleared the codes and the CEL light just comes back after a short time.

From what I can tell it's likely either a bad vacuum switching valve or a bad charcoal canister, which is possible since I did overfill my tank on a few occasions.

Anyone have any suggestions on how to test the canister? It's an expensive part to replace and hope it fixes the problem.

What was the problem? I have the same issue. Thanks.

https://www.google.com/search?q=p044...&client=safari

I had this code and cleared a few times. Changed the purge valve and canister at the same time. Fixed prob for about 1 year. Then it came back. i can guarantee you it was the canister for me because I live on dirt roads and it was filled with soft silted dirt. The 2nd time it happened I Attempted the same fix (purge valve under hood) canister replaced (get how expensive it is now)! Yikes- cleared codes- then started to get a really odd issue....vehicle would start easily in morning (cold start)...then I would drive 15 minutes...let it sit for 2 hours- get in and it would crank for a long time then start. I replaced fuel pump not OEM (dropped tank), fuel purge on rail NOT OEM (near firewall). same issue. I also started having issues at the pump...couldn't fill the tank...so I disconnected the line from charcoal canister to purge valve and it filled just fine. Still having issue with the warm start. I was told by a mechanic to replace the throttle body- which I did- started right up- put the canister line from purge valve back on and car died....now it wont start at all. When it was running I could hear a hissing turn on and off in the gas cap (yes I replaced the gas cap years ago as a first fix- OEM) but when I pulled the cap off....the vacuum let out but not fast like I expected- sounded like the vacuum was way further in the system- the system is pulling vacuum somewhere else. I have tried starting the vehicle without the canister attached at all but still plugged in....vehicle wont start. I'm at my wits end.