how to fix the P0420 code in my Skoda Octavia NFL (2020-Present)?

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Allow the vehicle to cool down before starting work.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet and extensions
• Remove the upstream and downstream oxygen sensors from the exhaust system.
• Inspect the connectors and wiring for damage.
• Install the new oxygen sensors, ensuring they are properly torqued according to manufacturer specifications (usually around 30 Nm).
• Reconnect the sensor harnesses.

3. Check and Replace the Catalytic Converter (if necessary)

• Tools Required: Socket set, torque wrench, exhaust clamps
• Remove the exhaust pipes connected to the catalytic converter.
• Unbolt the catalytic converter from its mounting brackets.
• Inspect the old catalytic converter for signs of blockage or damage.
• Install the new catalytic converter, ensuring proper alignment.
• Torque the bolts to manufacturer specifications (typically around 30 Nm).
• Reattach exhaust pipes and clamps securely.

4. Reset the Engine Control Module (ECM)

• Reconnect the negative battery terminal.
• Use an OBD-II scanner to clear the P0420 code from the ECM.
• Start the engine and let it idle to ensure the system is functioning properly.