Toyota 4Runner "Gas Cap' Codes. It wasn't the gas cap!

So for well over a year I've had these codes show up along with the skid control, check engine light, TRAC OFF VSC OFF light. PO43F, P2419, PO43E, P2402 and P2401.
I tried 4 different gas caps. Didn't work.
I did a Zero Point Calibration. Didn't work.
I blew out/cleaned the PVC valve (?), the charcoal canister, the Evap Pump back there, etc. Didn't work.
I did a smoke test on the system. Didn't work.
One evening I was thinking about it as I got a 2003 Tundra V8 that I'm driving now and my wife is driving the 4Runner. I got really good at ignoring those darn dash lights. My wife, not so much. Now that she's driving the T4R now I figured I'd better take another shot at figuring this out.
What finally worked for me was to sand down the top rim of the fuel filler neck where the gas cap O-ring is supposed to seal up against the filler spout. I was thinking about it one night and remembered a long time ago feeling that filler spout was kind of rough. I started thinking that maybe it was that and NOT the gas cap that was causing the issue.
I grabbed some 180 grit sandpaper, sanded down the top of the filler spout, cleared the codes and it's been almost three weeks now and the lights haven't come back on.
When I run the blue driver scan nothing shows up on the report. Hallelujah. So happy this finally worked.
If those darn lights have been driving you crazy too, hopefully this will work for you.

[@OverlandPNW]

Pure genius! I can't tell you how many times I've heard the gas cap story and it never worked!

[@abelm321]

Thank you so much . I just use 220 sand paper. Put the gas cap back . Turn on the car, and the lights are gone . Thank you so much . I was having the codes P0441 and 455. Thank you

[@ByebyeBiden]

Rub the ring with Vaseline

[@craigslistrro709]

Nothing more frustrating than being forced to throw money at a check engine light. Im doing it now.

[@Adirondacks4me]

Yikes 5 gas caps and I don't know what anything means or what any of those parts do other then knowing the word EVAP explains a lot. Even a blind squirrel finds a nut eventually...

[@daddios_6695]

We’re a two 4-runner family. My 04 was fixed when my broken speedo cable was replaced but my sons 4runner lights have been acting up for years. He just had it shipped down from Alaska and I tried several things. I saw your video and sanded the metal as you instructed and it’s been 2 weeks and several hundred miles and no warning lights so far. Thank you for the tip. Now can you help with tire pressure light 😅

[@brianzachary5618]

I did the same thing. I had bought a cap and got rid of the code for a few months. When the check engine light came back on I thought, I just bought a cap, and I saw there was a bit of rust on the filler neck. You being in Matagorda, rust is going to be an issue. A good part of the Texas coast is what is called hypersaline.

[@nghitran1433]

Hats off. You just made my Sunday. My 100k miles 2017 4runner got the same legendary gas cap code. 2 oem new gas caps, new oem maf sensor. And the issue come back. It has been intermittent. I tried sanding down the metal lip like you said. Voilaaaaa! Thanks so much

[@johnstaton671]

this was my problem. Sanded it down and installed the same cap and all lights were off. Didnt even have to drive it around to let it cycle....THANKS!! I had already ordered a new cap from Lexus and since it was springier I went ahead and swapped it, but the rough rim was my issue.

[@paulcali08]

I double layered the O Ring years ago, problem immediately fixed and no recurrence.

[@rasheeqmohammad9773]

Thank you very much for this video! People like you make UA-cam awesome. The sandpaper fixed my issue!

[@seanwise7464]

Appreciate the tip. I’m just beginning to go down this P0456 rabbit hole now, started with the 50$ OEM cap this morning.

[@filmsbydiek7316]

Gonna try this on the GX 470, chasing the P0456 code! Thanks for the tip and the vid!

[@bcap6031]

You’re a genius sir! My light went away now just have my tps light on. So happy thank you!!

[@greenjondear]

Great, inexpensive tip. I have two 4Runners ('04 (will be selling early Spring) and '07) with both displaying VSC, TRAC, Ck. Eng. lights. Looking forward to trying this out when a bit warmer (near Chicago with wind chill zero and dropping.)

[@zpoedog]

Thanks for the video. I have been having the same problem and getting tired of buying new gas caps that only work for a while.

[@davidstokes925]

WOW! Nice detective work!

[@OsotoMakikomi]

Great suggestion, will try

[@SkullNBones19]

Great Video!

[@lin018]

Thanks man.. I wasn't the lucky one. Good video