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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to prevent electrical shorts during repairs.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, wrench set, multimeter.
• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors on the exhaust system.
  2. Remove the connectors and unscrew the sensors using the O2 sensor socket.
  3. Install new oxygen sensors, ensuring they are tightened to the manufacturer's specifications (usually around 30 Nm).
  4. Reconnect the sensors and ensure all connections are secure.

3. Check and Repair Exhaust Leaks

• Tools Required: Exhaust leak tester, variable wrench set.
• Sub-steps:
  1. Use the exhaust leak tester to identify any leaks in the exhaust system.
  2. If leaks are found, replace or repair the affected exhaust sections.
  3. Ensure all connections are sealed and correctly torqued.

4. Replace Catalytic Converter (if necessary)

• Tools Required: Socket set, jack stands, cutting tools (if needed).
• Sub-steps:
  1. Raise the vehicle securely using jack stands.
  2. Disconnect the exhaust from the catalytic converter by removing the bolts or clamps.
  3. If necessary, cut the old catalytic converter out using cutting tools.
  4. Install the new catalytic converter, ensuring proper alignment and secure it with bolts to the specified torque (typically around 40 Nm).
  5. Reconnect the exhaust system and check for proper fitment.

5. Reconnect Battery and Clear Codes

• Reconnect the battery terminals.
• Use the OBD-II scanner to clear the P0421 code from the vehicle's computer.