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

Solution

1. Preparation

• Gather necessary tools and parts.
• Park the vehicle on a level surface, engage the parking brake, and disconnect the battery.
• Allow the engine to cool before working on the exhaust system.

2. Inspect and Replace Oxygen Sensors

• Sub-steps:
  1. Locate the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
  2. Unplug the electrical connectors from both sensors.
  3. Use a socket wrench to remove the oxygen sensors from the exhaust manifold and catalytic converter.
  4. Install new oxygen sensors, applying anti-seize compound to the threads if recommended.
  5. Reconnect the electrical connectors to the sensors.

3. Inspect and Replace the Catalytic Converter

• Sub-steps:
  1. Locate the catalytic converter in the exhaust system.
  2. Remove any heat shields if present, using a socket set.
  3. Use a wrench to unbolt the catalytic converter from the exhaust pipes.
  4. Inspect the old catalytic converter for signs of clogging or damage.
  5. Install the new catalytic converter, aligning it properly with the exhaust pipes.
  6. Torque the bolts to the manufacturer's specifications (refer to service manual for specific values).
  7. Reinstall any heat shields removed earlier.

4. Final Checks

• Sub-steps:
  1. Reconnect the battery.
  2. Start the engine and let it idle, checking for any exhaust leaks.
  3. Clear the P0420 code using the OBD-II scanner.
  4. Perform a test drive to ensure the check engine light does not reappear.