how to fix P0420 code on Honda Pilot Third Generation (2016-present)

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to ensure safety while working on the vehicle.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, torque wrench, penetrating oil.
• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors on the exhaust system.
  2. Use penetrating oil to loosen the sensors. Allow it to soak for a few minutes.
  3. Disconnect the electrical connectors from both oxygen sensors.
  4. Remove the sensors using the O2 sensor socket.
  5. Install new sensors, ensuring they are torqued to the manufacturer's specifications (typically around 30 lb-ft).
  6. Reconnect the electrical connectors.

3. Inspect and Replace Catalytic Converter (if necessary)

• Tools Required: Socket set, jack and jack stands, exhaust sealant.
• Sub-steps:
  1. Raise the vehicle securely on jack stands and remove any protective covers if necessary.
  2. Examine the catalytic converter for damage or blockages.
  3. If replacement is needed, unbolt the catalytic converter from the exhaust pipes and oxygen sensors.
  4. Install the new catalytic converter, ensuring all bolts are tightened to the specified torque (check manufacturer specs).
  5. Apply exhaust sealant to the joints if recommended by the manufacturer.

4. Clear Codes and Test Drive

• 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.
  3. Start the engine and allow it to reach operating temperature.
  4. Take the vehicle for a test drive to ensure no new codes appear and that the symptoms are resolved.