I got a P0456 (small leak in EVAP) and on the Jeep forum it mentioned several people had replaced the gas cap and the issue went away. The gas caps they replaced were normal looking, no visable damage ones.
Do gas caps wear out
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The seal or spring for the check valve in them dry out, get debris stuck in them or just plain wear out. They then stick open and the vehicle won't pass it's EVAP system test.
Yup, just had the exact same thing occur on the CVPI. Popped a P0456. Replaced the cap just because it was as old as the car, which ended up being the problem.
Like JTK said, the seal dries out, or gets something stuck in it.
Like JTK said, the seal dries out, or gets something stuck in it.
I put a locking gas cap on years ago.
I put the original in the glove box.
I put the original in the glove box.
Yeah, but thieves can still get in through the check valve.
I'm kidding.
I'm kidding.
Yes, happened this past year with my Tahoe. Rubber O ring was nicked.
Yes. They test the cap as part of the emissions test here
I've had to replace a couple gas caps in the past due to them just getting old and throwing a code.
Now neither of my vehicles have gas caps
Now neither of my vehicles have gas caps
You can usually slip a vacuum hose over the valve part of a gas cap. A good one will "quack" under light pressure or vacuum as the reed valve releases pressure. A lame one will hiss.
As unscientific as this is, you can do it to compare new vs old. Any gas fumes you breathe in the process are a bonus for your unborn children.
As unscientific as this is, you can do it to compare new vs old. Any gas fumes you breathe in the process are a bonus for your unborn children.
My Subaru Outback had a CEL pop up, while on a trip, 6 months old, 15k miles. First thing I confirmed was cap tightness.
After a going over, the dealer I took it to replaced the cap. Has not happened since, in over 75k miles and 3 years. So....They don't have to be old......They can just be bad.
Interestingly, the new cap had a different color gasket....Original was black, new one brown. But I suspect the problem was internal to the cap.
After a going over, the dealer I took it to replaced the cap. Has not happened since, in over 75k miles and 3 years. So....They don't have to be old......They can just be bad.
Interestingly, the new cap had a different color gasket....Original was black, new one brown. But I suspect the problem was internal to the cap.
Yes, I replaced the cap on the Dakota last year for the same reason. $10 or so at NAPA and the CEL went off a day later.
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