how to fix P0420 code in my Honda Pilot Third Generation (2016-present)?

Solution

1. Preparation

• Gather all tools and parts needed for the repair.
• Disconnect the battery to ensure safety while working on electrical components.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench.
• Sub-steps:
  1. Locate the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
  2. Disconnect the electrical connectors from both sensors.
  3. Remove the sensors using the O2 sensor socket.
  4. Install the new sensors, ensuring they are tightened to the manufacturer's specified torque (typically around 30 ft-lbs).
  5. Reconnect the electrical connectors.

3. Inspect and Replace the Catalytic Converter

• Tools Required: Socket set, torque wrench, cutting tool (if necessary).
• Sub-steps:
  1. Inspect the catalytic converter for signs of damage or blockage.
  2. If replacement is necessary, unbolt the exhaust pipes connected to the catalytic converter.
  3. Remove the old catalytic converter and replace it with a new one.
  4. Ensure all bolts are tightened to the manufacturer's specified torque.
  5. Reconnect the exhaust system.

4. Clear the Error Code

• Tools Required: OBD-II scanner.
• Sub-steps:
  1. Reconnect the battery.
  2. Use the OBD-II scanner to clear the P0420 code from the vehicle's computer.

5. Final Inspection

• Start the engine and let it run for a few minutes to check for any leaks or unusual noises.
• Monitor the exhaust flow and ensure it is free of obstructions.