Gas cap light and check engine light

I have a 2023 4Runner Limited. It has around 9500 miles on it. In the last month I've had to take it to the dealer 3 times because I get a gas cap light and the next day my check engine light comes on. They say it's not showing any problems when they hook it up. They reset it the 1st time. They reset the 2nd time and replaced the gas cap. A few days later the damn thing came on again. This time they're going to keep it and see if they can figure it out. Anyone else having this problem?

 

Do you "top off" when filling up?

 

No. I also don't leave the engine on when I fill up and I always make sure it "clicks" when I close it. They asked me those questions at the dealership.

 

It's probably just a bad cap.

 

2nd visit to the dealership they put a new cap on. 2 days later, same issue.

 

Other things can trigger the small EVAP leak. They will have to smoke test the system.

 

I just went to Napa and bought a keyed gas cap. part # 7031689. 2nd day of use we got a engine service light and check gas cap message. I was just looking at both caps and there is a spring relief on the stock cap. So I'm thinking the spring is a pressure relief as gas will expand with heated. As mentioned by whipper, a smoke test should show a leak somewhere. What I'd like to know is the system under pressure or is it in a vacuum state when engine is running. I've watched AMD, The car care nut U-Tube channel talk about the fuel/vapor system and talks about not over filling the fuel tank. Let us know the issue when it's fixed. Thanks

 

I just got it back from the dealership a few days ago. It was the 4th time in a little over a month I had to drop it off. I'm not a mechanic so I can't remember the proper names of the part but they decided there must be a problem with the cylinder, where you put the gas in. They said replacing that and the sensor should fix it. A few days later they called back and said the fuel tank had a Crack in it. They replaced it. I've driven it a couple of times since and put gas in. So far, so good.

 

If there is an EVAP related light, there is a leak somewhere ,however small it may be.
I had to spend considerable time and money to identify my leak.
Yours is in warranty, so any such issues should be covered. No reason for a brand new car to throw a CEL due to a faulty EVAP system.

 

Thanks for the update

 

The gas cap light is typically only triggered by large evap leaks, small evap leaks usually just give a check engine light. When it’s a large leak and not the gas cap it’s a very easy diagnosis with a smoke machine, assuming someone spends the time to do it.