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Q: Failed smog check

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My vehicle did not pass smog due to code P0455.

Hi. This is a fairly common concern for smog failure, it indicates the computer has detected a large leak in the evaporative emissions system. 90% of the time this is due to the fuel cap not being secured properly. Sometimes, a defective cap altogether would trigger this code. Have a mechanic, like one from YourMechanic, come and inspect the fuel cap and reset the Check Engine Light. Remember, after reseting the codes, the car must be driven for 50-75 miles to ensure all of the computer on board diagnostic drive cycles have completed before smog testing.

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