Skoda Octavia NFL (2020-Present) check engine light and code P0420, what should I do?

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Disconnect the battery to ensure safety while working on electrical components.

Tools Required:

• OBD-II scanner
• Socket set
• Torque wrench
• Multimeter
• Jack and jack stands

2. Inspect and Replace Oxygen Sensors

1. Locate the upstream and downstream oxygen sensors.
2. Disconnect the electrical connectors from both sensors.
3. Remove the sensors using a socket wrench.
4. Install new sensors, ensuring they are torqued to the manufacturer's specifications (typically 30 lb-ft).
5. Reconnect the electrical connectors.

3. Inspect and Replace Catalytic Converter (if necessary)

1. If the catalytic converter appears damaged or if tests indicate failure:
   • Loosen and remove the exhaust clamps and bolts securing the catalytic converter to the exhaust system.
   • Carefully remove the catalytic converter from the vehicle.
2. Install the new catalytic converter:
   • Position it in place and secure it with the clamps and bolts.
   • Ensure all connections are tight and sealed.
3. Reconnect any sensors that were disconnected and inspect for proper fitment.

4. Reset the Engine Control Module (ECM)

1. Reconnect the battery.
2. Use the OBD-II scanner to clear the check engine light and reset the ECM.
3. Start the engine and allow it to idle for a few minutes.