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Help! P0420 Code

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Old May 1, 2023 | 07:34 PM
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2024 Mercedes-Benz E350
Help! P0420 Code

This code came on today, and I ran it with my scanner. Car is a 2015 S550 with 68,000 miles. Called the dealer and couldn't get in until Monday the 15th. Called my independent, and I dropped it off tonight, and he thinks it's hopefully the oxygen sensor or possible the catalytic converter. Hopefully nothing else. What does everyone think?

Any help is appreciated!





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Old May 1, 2023 | 07:48 PM
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Check component 'G3/3 (Left oxygen sensor upstream of catalytic converter
likely just that to replace
btw, replace both, never just one side
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Old May 1, 2023 | 07:49 PM
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2024 Mercedes-Benz E350
Originally Posted by BenzNinja
Check component 'G3/3 (Left oxygen sensor upstream of catalytic converter
likely just that to replace
btw, replace both, never just one side
Thanks! He's gonna call me tomorrow!
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Old May 1, 2023 | 07:51 PM
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Originally Posted by snarestud940
Thanks! He's gonna call me tomorrow!
don't worry too much
I see this 10x per week
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Old May 1, 2023 | 07:52 PM
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2024 Mercedes-Benz E350
Originally Posted by BenzNinja
don't worry too much
I see this 10x per week
I appreciate the advice! I just love this car and am so tired of every little thing going wrong lol. I doubt the catalytic converter actually went.
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Old May 1, 2023 | 07:56 PM
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Originally Posted by snarestud940
I appreciate the advice! I just love this car and am so tired of every little thing going wrong lol. I doubt the catalytic converter actually went.
you are welcome
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Old May 2, 2023 | 12:55 PM
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He just called. He says hes not sure, but says lets start with the oxygen sensors on the right, and go from there. He doesn't want me spending the thousands of dollars for the catalytic converter if we don't have to. Will be done today!
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Old May 2, 2023 | 04:06 PM
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Originally Posted by snarestud940
He just called. He says hes not sure, but says lets start with the oxygen sensors on the right, and go from there. He doesn't want me spending the thousands of dollars for the catalytic converter if we don't have to. Will be done today!
I do not see a cat fail with that mileage
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