how to fix P0421 code in Renault Clio V (2019-Present)

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Disconnect the battery to prevent electrical shorts.
• Allow the vehicle to cool down before working on exhaust components.

2. Inspect and Replace O2 Sensors

• Tools Required: O2 sensor socket, wrench, multimeter.
• Locate the upstream and downstream O2 sensors.
• Disconnect the electrical connectors from each sensor.
• Remove the sensors using the O2 sensor socket.
• Test the sensors with a multimeter to check for proper resistance values.
• If faulty, install new O2 sensors, ensuring they are properly torqued to manufacturer specifications (usually around 30-40 Nm).
• Reconnect the electrical connectors.

3. Inspect and Replace the Catalytic Converter

• Tools Required: Socket set, torque wrench, exhaust gasket.
• Locate the catalytic converter in the exhaust system.
• Disconnect the exhaust pipe at both ends of the catalytic converter by removing the bolts or clamps.
• Check for any signs of damage or blockage inside the converter.
• If necessary, replace the catalytic converter with a new unit, making sure to use a compatible part.
• Reinstall the exhaust pipe, ensuring all connections are tight and use a new gasket if required.

4. Clear Codes and Test Drive

• Reconnect the battery.
• Use the OBD-II scanner to clear the P0421 trouble code.
• Start the engine and let it reach operating temperature.
• Conduct a test drive to ensure the vehicle performs well and check for the reappearance of the code.