how to fix P0420 code on my Honda Pilot YF4 (2023-Present)

Solution

1. Preparation

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

2. Inspect and Replace Oxygen Sensors (if necessary)

• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors on the exhaust manifold and catalytic converter.
  2. Disconnect the electrical connectors from the sensors.
  3. Use an oxygen sensor socket to remove the sensors from the exhaust system.
  4. Install the new oxygen sensors and reconnect the electrical connectors.
  5. Torque the sensors to manufacturer specifications (typically around 30-40 ft-lbs).

3. Inspect and Replace Catalytic Converter (if faulty)

• Sub-steps:
  1. Remove the exhaust pipe or any components obstructing access to the catalytic converter.
  2. Use a wrench to remove the bolts securing the catalytic converter to the exhaust system.
  3. Carefully remove the old catalytic converter.
  4. Install the new catalytic converter, ensuring a proper fit.
  5. Torque the bolts to the manufacturer’s specifications (typically around 25-30 ft-lbs).
  6. Reinstall any removed exhaust components.

4. Reset the ECU

• Sub-steps:
  1. Reconnect the battery terminals.
  2. Use an OBD-II scanner to clear the P0420 code from the ECU.
  3. Start the engine and allow it to reach operating temperature.