I've got an o8 4Runner Sport. It's throwing codes, P0455 == Evaporative Emission System Leak Detected (gross leak/no flow) and code, P0441 == Evaporative Emission System Incorrect Purge Flow.

When this happens the Check Engine, VSC and Skid Control lights come on. I replaced the gas cap, and cleared all codes. This morning the lights were again on. I do have a tendency to fill the tank "Completely full. I've found that when the pump initially shuts off, The tank will take another 2.5 gallons. This morning I decided to look for the Evap Canister. What I discovered was this. The filler opening is approx. 2" in diameter. The hose attached to the filler opening necks down to a 1.25" hose which has a vertical drop of around 12" and then has a about a 24" to 30" horizontal run to the tank.

My thinking is this, due to the configuration of the fill system, the extra 2.5 gallons I've been putting in the tank after pump auto shutoff, has been saturating the Evap Canister.

I'm unsure which of the two items connected to the fuel fill system is the Evap Canister.

Any help would be appreciated. Thanks.

You are absolutely correct in your assumptions about saturating it with the excess gas. Used to do the same thing, got an evap code and took it to the dealer. Fortunately, for me, mine had been eaten by squirrels but was also saturated with gas. Fortunate because insurance covered the replacement ($800+ IIRC). Service guy, who I actually trusted, said overfilling is bringing these things in all the time. When the pump cuts off, you're done. I don't know that I ever got another 2.5 gallons in, usually 1 or a little less.

Search this forum or YouTube, can't remember where I saw it but there's a guy who "rebuilt" his evap canister and it work like new, basically he was able to open it up and replace the charcoal inside with new charcoal and had no more issues.

Edit: It was YouTube, here's the link.

https://youtu.be/RBirjoKGNiA

Yep, I had all of those codes awhile back, and while researching, I found out about the overfilling problem. I don’t personally do that, but my wife ALWAYS does with her Camry, so I warned her about the cost of replacing that system on Toyotas. I’m not even sure if it’s a problem on her 2016 XSE, but I definitely didn’t want to find out the hard way! I’m also more careful with my 4Runner now too as a result. In my case, I had a fairly large hole in the big corrugated plastic hose that goes to the tank. It was right at the connection to the canister, so I was able to patch it with JB Weld, and it solved my problem. I still have no clue how the hole got there in the first place though.

I've had the same problem with the cutoff when putting gas into my 2002 4Runner. Replace the charcoal canister thinking that was the solution, but I still have the gas backing out when I try to fill the tank. I'm running out of possible answers (and patience). What should I do next?