No, the 420 is a catalytic converter efficiency code. The internals are not processing the gases correctly.
The converter needs to be replaced.
I attached the procedure for you below for the replacement and I also posted the part from Rockauto.
If you go with the sensors, the code will keep coming back until you replace the converter.
Roy
Catalytic Converter Replacement
Removal Procedure
Notice: To prevent internal damage to the flexible coupling of the catalytic converter assembly, the converter must be supported. The vertical movement at the rear of the catalytic converter assembly must not exceed 6 degrees up or down.
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1. Raise and support the vehicle. Refer to Vehicle Lifting.
2. If the vehicle is equipped with All-Wheel-Drive (AWD), remove the propeller shaft.
3. Remove the catalytic converter to exhaust manifold nuts.
4. Remove the heated oxygen sensor (HO2S).
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5. Remove the catalytic converter to muffler bolts.
6. Remove and discard the catalytic converter to muffler gasket.
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7. If equipped with regular production option (RPO) LX9 and front wheel drive (FWD), remove the catalytic converter (1).
8. If equipped with RPO LX9 and AWD, remove the catalytic converter (2).
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9. If equipped with RPO LY7 and FWD, remove the catalytic converter (1).
10. If equipped with RPO LY7 and AWD, remove the catalytic converter (2).
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Saturday, November 14th, 2020 AT 4:16 AM