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

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the negative battery terminal to avoid electrical shorts.
• Allow the exhaust system to cool down before starting work.

2. Inspect and Replace Oxygen Sensors (if faulty)

• Tools Required: O2 sensor socket, ratchet, torque wrench, penetrating oil (if needed).
• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors in the exhaust system.
  2. Apply penetrating oil to the sensor threads if they are corroded.
  3. Use the O2 sensor socket to remove the sensors.
  4. Install the new oxygen sensors, tightening them to the manufacturer's torque specification (typically around 30 Nm).
  5. Reconnect the electrical connectors for the sensors.

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

• Tools Required: Socket set, jack and jack stands, exhaust pipe cutter, welding equipment (if needed).
• Sub-steps:
  1. Raise the vehicle and support it securely on jack stands.
  2. Remove any heat shields or brackets obstructing access to the catalytic converter.
  3. Cut the exhaust pipes using an exhaust pipe cutter or saw if necessary.
  4. Remove the catalytic converter from its mounting.
  5. Install the new catalytic converter, ensuring proper alignment and sealing.
  6. Reattach any heat shields and brackets removed earlier.

4. Reset the ECU

• Tools Required: OBD-II scanner.
• Sub-steps:
  1. Reconnect the negative battery terminal.
  2. Use an OBD-II scanner to clear the P0420 code from the ECU.
  3. Start the engine and let it run for a few minutes to ensure everything is functioning correctly.