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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the vehicle’s battery to prevent electrical issues.
• Allow the engine to cool completely before starting work.

2. Inspect and Replace Oxygen Sensors

1. Locate the upstream and downstream oxygen sensors: These are typically found before and after the catalytic converter.
2. Remove the sensors: Use an oxygen sensor socket to unscrew the sensors from their locations.
3. Install new oxygen sensors:
   • Apply anti-seize compound to the threads of the new sensors.
   • Install the upstream sensor first, followed by the downstream sensor, tightening them to the manufacturer's specifications (usually around 30 lb-ft).
4. Reconnect the battery.

3. Inspect and Replace Catalytic Converter

1. Remove the exhaust components: Depending on your setup, you may need to remove exhaust pipes or heat shields to access the catalytic converter.
2. Unbolt the catalytic converter: Use a socket set to remove bolts connecting the converter to the exhaust system.
3. Inspect the catalytic converter: Look for signs of damage, rattling sounds, or blockages. If damaged, replace it with an OEM or high-quality aftermarket part.
4. Install the new catalytic converter:
   • Position the new converter and secure it with bolts, tightening to the manufacturer's specifications (usually around 30-50 lb-ft).
   • Reattach any exhaust components removed earlier.

4. Reset the OBD-II System

• Use an OBD-II scanner to clear any stored codes from the vehicle's computer.
• Start the engine and let it idle for a few minutes to ensure everything is functioning properly.