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

Solution

1. Preparation

• Gather tools and parts needed.
• Disconnect the battery to prevent electrical shorts.
• Allow the engine to cool before working on the exhaust system.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench.
• Remove the upstream oxygen sensor (pre-cat) using the O2 sensor socket.
  • Sub-step: Disconnect the electrical connector by pressing the tab and pulling it apart.
• Install the new sensor and torque to the manufacturer's specification (usually around 30 Nm).
• Repeat the process for the downstream oxygen sensor (post-cat) if necessary.

3. Inspect and Replace Catalytic Converter

• Tools Required: Socket set, jack and jack stands, penetrating oil (if bolts are rusted).
• Support the vehicle securely on jack stands.
• Remove any heat shields or brackets obstructing access to the catalytic converter.
• Unbolt the catalytic converter from the exhaust system using a socket set.
  • Sub-step: Use penetrating oil on rusty bolts to ease removal.
• Install the new catalytic converter, ensuring proper alignment with the exhaust system.
• Torque all bolts to the manufacturer's specifications.

4. Clear Codes and Test

• Tools Required: OBD-II scanner.
• Reconnect the battery.
• Use the OBD-II scanner to clear the P0420 code.
• Start the vehicle and let it reach operating temperature.