Code P0420 Emissions system

2016 CHEVROLET SONIC
90,000 MILES • 1.4L • 4 CYL • 4WD • AUTOMATIC
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COUNTRYGIRL20053
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  • 6 POSTS
We have replaced the fuel cap and have changed one purge value and after a couple of days the check engine light came back on. so, we put another purge value on it, and it didn't come back on in over a week, and this morning i used auto start and it came right on after i got in the car. Would there be a reason why it could be doing this or is there another reason why?
Nov 29, 2021 at 11:28 AM
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JACOBANDNICKOLAS
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  • 110,175 POSTS
Hi,

The code, P0420, is related to a catalytic converter not operating properly. Is this the only code you have? I ask because it could be related to the heated oxygen sensor as well. However, if there is no code for the sensor, chances are the converter needs replaced.

Take a look at the pic below. It provides a basic inspection of the converter. Check through it and perform any of the steps you can and let me know the results.

Take care,

Joe

See pic below.
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Nov 29, 2021 at 6:35 PM