how to fix P0420 code in Renault Clio V (2019-Present)

Solution

1. Preparation

• Gather tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Allow the vehicle to cool if the engine has been running recently.

2. Inspect and Replace Oxygen Sensors (if faulty)

1. Locate the upstream and downstream oxygen sensors on the exhaust manifold and catalytic converter.
2. Use an O2 sensor socket to remove the faulty sensors.
3. Install new oxygen sensors, ensuring they are properly torqued according to specifications (usually around 30 lb-ft).
4. Reconnect the electrical connectors securely.

3. Inspect and Replace Catalytic Converter (if necessary)

1. Remove any heat shields or brackets obstructing access to the catalytic converter.
2. Disconnect the exhaust pipes at the flanges using a socket set, and support the exhaust system as needed.
3. Remove the catalytic converter from its mounting points.
4. Install the new catalytic converter, ensuring proper fitment.
5. Reconnect the exhaust pipes and tighten all bolts to the manufacturer's torque specifications (typically around 25 lb-ft).
6. Reinstall any heat shields or brackets.

4. Reset the Engine Control Module (ECM)

1. Reconnect the negative battery terminal.
2. Use an OBD-II scanner to clear the P0420 code from the ECM.
3. Start the engine and allow it to reach operating temperature.