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

Solution

1. Preparation

• Ensure the vehicle is parked on a flat surface and the engine is cool.
• Disconnect the negative terminal of the battery to prevent any electrical shorts.
• Gather necessary tools and parts.

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. Using the O2 sensor socket, carefully remove the old sensors.
  3. Install the new sensors and torque them to the manufacturer’s specifications (typically around 30 lb-ft).
  4. Reconnect electrical connectors to both oxygen sensors.

3. Inspect and Replace Catalytic Converter (if necessary)

• Tools Required: Socket set, jack and jack stands, exhaust pipe cutter (if needed).
• Sub-steps:
  1. Raise the vehicle using a jack and secure it with jack stands.
  2. Remove any heat shields or mounting brackets obstructing access to the catalytic converter.
  3. Cut the exhaust pipe if necessary, using the exhaust cutter, to remove the old catalytic converter.
  4. Install the new catalytic converter by reversing the removal process. Ensure all connections are secure and leak-free.
  5. Reinstall any heat shields or brackets.

4. Reconnect Battery and Clear Codes

• Reconnect the negative battery terminal securely.
• Use the OBD-II scanner to clear the P0420 code from the vehicle's computer.