Anyone experienced a P0420 catalyst low efficiency code???

[Bra1nDamag3d]

Sounds like you might be about to get the code p0449 as well
The wiring that goes to the vapor canister behind the pass rear wheel is known to fail due to its location. Run new wiring and the p0171 should go away. As for the p0420, i had it and changes my upstream o2 sensor n it hasn't returned.

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[09aveo5-LS-5SP]

Sounds like you might be about to get the code p0449 as well
The wiring that goes to the vapor canister behind the pass rear wheel is known to fail due to its location. Run new wiring and the p0171 should go away. As for the p0420, i had it and changes my upstream o2 sensor n it hasn't returned.

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I have replaced a lot of wiring and plugs on top of the motor and underneath cracked with slight corrosion


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