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

Solution

1. Preparation

• Gather all tools and parts required.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the battery to prevent electrical shorts.

2. Inspect and Replace Oxygen Sensors

• Sub-steps:
  • Locate the upstream and downstream oxygen sensors.
  • Remove the connectors from both sensors.
  • Use an O2 sensor socket to remove the old sensors.
  • Install new oxygen sensors, ensuring to torque them to manufacturer specifications (usually around 30 lb-ft).
  • Reconnect the electrical connectors securely.

3. Inspect and Replace Catalytic Converter

• Sub-steps:
  • Locate the catalytic converter.
  • Use a socket set to remove any bolts or nuts securing the catalytic converter to the exhaust system.
  • Carefully lower the catalytic converter out of the exhaust system.
  • Install the new catalytic converter, ensuring proper alignment with exhaust flanges.
  • Torque the bolts to the manufacturer’s specifications (usually around 25 lb-ft).
  • Reconnect any sensors or heat shields that were removed.

4. Reset the Engine Control Module (ECM)

• Sub-steps:
  • Reconnect the vehicle battery.
  • Use an OBD-II scanner to clear the P0420 code from the ECM.
  • Start the engine and let it idle for a few minutes.