how to fix P0420 code on my Honda Pilot YF3 (2016-2022)

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a level surface with the engine off and cooled down.
• Disconnect the negative battery terminal to ensure safety.

2. Inspect and Replace Oxygen Sensors (if faulty)

• Tools Required: O2 sensor socket, torque wrench, new oxygen sensors.
• Sub-steps:
  1. Remove the upstream and downstream oxygen sensors from the exhaust system using an O2 sensor socket.
  2. Inspect the sensors for any signs of damage or contamination.
  3. Install new oxygen sensors by threading them into the exhaust system and tightening to the manufacturer's torque specifications (usually around 30 lb-ft).
  4. Reconnect the electrical connectors to the new sensors.

3. Inspect and Replace Catalytic Converter (if necessary)

• Tools Required: Socket set, torque wrench, new catalytic converter, gasket (if applicable).
• Sub-steps:
  1. Remove the exhaust pipe bolts connecting to the catalytic converter using a socket set.
  2. Carefully detach the catalytic converter from the exhaust system.
  3. Inspect the mating surfaces for cleanliness and any damage.
  4. Install the new catalytic converter, ensuring proper alignment with the exhaust system.
  5. Tighten the bolts to the manufacturer’s torque specifications (usually around 30 lb-ft).
  6. Replace any exhaust gaskets if needed to prevent leaks.

4. Reset the Engine Control Module (ECM)

• Tools Required: OBD-II scanner.
• Sub-steps:
  1. Reconnect the negative battery terminal.
  2. Use the OBD-II scanner to clear the P0420 code from the ECM.
  3. Perform a test drive to allow the ECM to monitor the new components.