Hi,
Both of these codes are related to a catalytic converter that is performing under the threshold set by the manufacturer.
P0420 is a bank 1 catalyst efficiency
P0430 is a bank 2 catalyst efficiency
From experience, in most cases, the converter will need to be replaced. However, there are other things that can set the codes such as a faulty oxygen sensor or wiring problem. Basically, the ECM has identified an O2 sensor with a low switching frequency (heated O2 sensor/sensor 2). You can confirm that by using a live data scan tool to watch voltage changes from a specific sensor.
Here are two links you may find of interest:
https://www.2carpros.com/articles/how-an-oxygen-sensor-works
https://www.2carpros.com/articles/how-to-test-an-oxygen-sensor-02-sensor
One more thought. Here is a link related to the symptoms of a failing catalytic converter. Hopefully, it will help you.
https://www.2carpros.com/articles/bad-catalytic-converter-symptoms
I hope this helps. Let me know if you have other questions.
Take care,
Joe
Nov 7, 2021 at 12:48 PM
