Posts Tagged: Code P0420
Code P0420: What it means and what to do about it
Learn what code P0420 means and how to fix it A P0420 code means your catalytic converter has failed an efficiency test. In other words, it’s not removing harmful combustion byproducts from the exhaust. Many people think that the way to fix code P0420 is to replace the oxygen sensors. That’s wrong. In fact, the vehicle computer can’t even come to the conclusion that your catalytic converter has failed the efficiency test if your oxygen sensors are bad. So, don’t waste your time and money on oxygen sensors. What to … Read More
P0420 Catalyst System Efficiency
P0420 Catalyst System Efficiency Below Threshold (Bank 1) Code P0420 Catalyst System Efficiency Below Threshold (Bank 2) NOTE: Codes P0420 and code P0430 are similar. I wrote a much more detailed explanation of how an emission system works and what causes these codes. Read this post and then refer to this more detailed post. Code P0420 means the catalytic converter for bank 1 has failed it’s testing. The oxygen sensor in front of the catalytic converter switches back and forth between rich and lean as the computer constantly changes air … Read More