How to Fix a Bad Catalytic Converter and the P420 Code - The Ultimate Guide

🚗A P420 code indicates low catalyst system efficiency and malfunctioning downstream sensor. A dirty cat is often the culprit.

💰Replacing a catalytic converter can be expensive, especially for older cars with high mileage. Alternative solutions can save you money.

⚙️Using catalytic converter cleaners like Cataclean can improve efficiency and reduce emissions. Follow instructions carefully for best results.

🚧Spacer installation can trick the downstream sensor and prevent the check engine light from coming on. However, this is not recommended and may be illegal.

😂This video provides both informative content and entertaining commentary from the Backyard Mechanic.

What does a P420 code mean?

—A P420 code indicates a low catalyst system efficiency and that the downstream oxygen sensor has detected oxygen levels below the threshold on Bank 1.

Is it necessary to replace a bad catalytic converter?

—While it is recommended to replace a bad catalytic converter, there are alternative solutions that can be effective, such as using catalytic converter cleaners.

Can a catalytic converter cleaner fix the issue?

—Catalytic converter cleaners like Cataclean can improve efficiency and reduce emissions. However, results may vary, and it is important to follow the instructions carefully.

Is it legal to use spacers to trick the sensor?

—Using spacers to trick the downstream sensor is not recommended and may be illegal. It is important to comply with local regulations and follow proper procedures.

What makes this video unique?

—This video provides not only informative content on fixing catalytic converters but also entertaining commentary from the Backyard Mechanic.

00:00Introduction to the issue of bad catalytic converters and the P420 code.

01:06Explanation of how to determine if the catalytic converter is dirty based on the tailpipe.

02:00Discussion on the high cost of catalytic converter replacements for older cars.

02:53Explanation of using catalytic converter cleaners as a cost-effective solution.

04:11Caution against using spacers to trick the downstream sensor and the potential legal implications.

06:00Step-by-step demonstration of removing and installing spacers for the sensors.

08:09Final remarks and disclaimer, with an invitation to watch other entertaining videos from the Backyard Mechanic.