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P0456 Concers

Hello everyone, my Jeep recently came up with a CEL after pumping gas sometime last week. It happened about an hour after so I did some research and they said one solution could be that my gas cap may be lose or needs replacement. I then removed and made sure the cap was secured properly. After about two days the CEL stopped showing up. I just took my Jeep to an AutoZone and was told that the reader was still detecting the issue. Should I be worried??? Any help would be appreciated


It just means the readiness monitors for the EVAP system haven’t reset.

Drive the vehicle normally, and the readiness monitors for the EVAP system should reset.


fyi, here’s how the Chrysler evap systems work. Jeep is a division of Chrysler, right?

Thanks for the quick responses. I’ll update once I’ve checked the link provided.

If I understand this correctly; the check engine light is no longer on but the scan tool showed a stored fault.

The fault will remain in the computers memory for 255 ignition cycles or until erased with a scan tool or battery disconnect. Forget about it if the light remains off.

You are correct. After I pumped gas a second time and made sure to properly secure the gas cap the CEL went away after a day or so. I then went to the AutoZone afterwards and was told it was still reading the issue. I will get it erased since I haven’t had a CEL show up in the past week. Thank you all for your help.

Autozone wanted you to buy a gas cap.

The guy didn’t offer one to me. He printed out my diag. I thanked him and left.


your gas cap . . . what condition is the seal in?

Nice and pliable?

Cracked and/or chunks missing?

Not cracked or chunks missing. It is however odd to seal it. Seems like even when I hear it click when I tighten it that it doesn’t even lock properly. I just thought the cap was very basic/cheap