how to fix P0420 code in Honda Civic 11th Generation (2022-Present)?

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery negative terminal to ensure safety during repairs.

2. Inspect and Replace Oxygen Sensors

• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors on the exhaust manifold and catalytic converter.
  2. Unplug the electrical connectors from both oxygen sensors.
  3. Use an oxygen sensor socket to remove the sensors from the exhaust system.
  4. Install the new oxygen sensors and torque them to the manufacturer's specifications (usually around 30 lb-ft).
  5. Reconnect the electrical connectors to both sensors.

3. Inspect and Replace the Catalytic Converter

• Sub-steps:
  1. Remove any heat shields or covers obstructing access to the catalytic converter.
  2. Disconnect the exhaust pipes from the catalytic converter by removing the clamps or bolts; use penetrating oil if necessary.
  3. Remove the catalytic converter by unbolting it from its mounts.
  4. Install the new catalytic converter, ensuring proper alignment.
  5. Reconnect the exhaust pipes and torque the bolts to the specified values (usually around 25 lb-ft).
  6. Reinstall any heat shields or protective covers.

4. Reconnect the Battery

• Reconnect the battery negative terminal.

5. Clear the Codes

• Use an OBD-II scanner to clear the P0420 code and any other related codes.