how to fix P0420 code on my Skoda Octavia NFL (2020-Present)

Solution

1. Preparation

• Gather tools and parts.
• Disconnect the battery to ensure safety.
• Allow the exhaust system to cool before working on it.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, wrench set.
• Remove the upstream (pre-catalytic) oxygen sensor using the O2 sensor socket.
• Inspect the sensor for damage or contamination.
• Replace if necessary with a compatible OEM or quality aftermarket sensor.
• Repeat the process for the downstream (post-catalytic) oxygen sensor if it shows signs of failure.

3. Inspect and Replace Catalytic Converter

• Tools Required: Socket set, jack and jack stands, exhaust pipe cutter (if necessary), gasket scraper.
• Safely lift the vehicle using a jack and secure it with jack stands.
• Remove the bolts securing the catalytic converter to the exhaust system using the socket set.
• If necessary, use an exhaust pipe cutter to separate the catalytic converter from the exhaust pipes.
• Inspect the mounting surfaces for any debris or gasket material; clean if needed.
• Install the new catalytic converter, ensuring a proper fit and alignment.
• Use new gaskets or seals as required by the manufacturer.

4. Reconnect Battery and Clear Codes

• Reconnect the vehicle's battery terminals.
• Use the OBD-II scanner to clear the P0420 code from the vehicle's computer.