Check engine light is on and codes P0420 and P0430

Good morning,

Yes, you need to replace both catalytic converters. This is not a code for O2 sensors. It is a code that says the precious metals in the catalytic converters are worn out.

They need to be replaced.

Roy

Hello,

Yes, direct Trouble Codes [DTC][s] P0420 and P0430 are DTC's that set when your vehicle's Catalytic Converters have reached the end of their useful life and need to be replaced. There is a quick trick that will turn the Malfunction Indicator Lamp [MIL] off, but I'm not sure about passing smog. There are after market products called "cat deletes", available on Amazon or Ebay, that go inline in between the wiring harness and the rear O2 electrical connector. This product takes the battery voltage that would be intended for the O2 heater and runs it through a resistor to bring it's voltage to about 1/2 Volt and then turns it around and sends it to the Power-train Control Module [PCM]. This 1/2 volt reading to the PCM tricks it into thinking that the Catalytic Converter is operating as it should and is okay. The second option, and the one I would recommend, is to replace the catalytic converters and fix your vehicle properly. Here is a link below explaining how to replace them:

https://www.2carpros.com/articles/catalytic-converter-replacement

Please go through this guide and get back to us with what you decide to do and how it turns out.

Thanks,
Alex
2CarPros

Have yet to see those units actually work without setting an O2 code because they don't switch at all. Plus they are illegal in most areas as they constitute tampering with the emissions system.
Replacement of the catalytic converters is the better option, just be sure if you are in one of the states that restrict which catalytic converters you can use for replacement you get the correct parts.