P0420 code

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osidesurfer365

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Check engine light went on the other day and Onstar notified me it was P0420. I replaced all 4 O2 sensors with AC Delco ones. Do I need to drive a certain amount of miles before the check engine turns off. Hoping I don’t have to replace the actual converter. Thanks


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Matthew Jeschke

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You can delete codes with a scanner. Or disconnect your battery for 10 minutes. Then reconnect and start up truck. Battery method will also whipe out your fuel trims so may run a tad rich for a short while.

At least that works on older stuff. My truck is 2001.

If code comes back maybe another issue / need further troubleshooting.

Before anything else i wojld double check connectors. Also aways nice to have a cheap scan tool, some can read sensors themselves, then you know immediately if is disconnected or reading wrong.

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osidesurfer365

osidesurfer365

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Thanks for the response. Turns out after driving it about 70 miles it turned off and no other codes came on when I plugged the scanner in.


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