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

Solution

1. Preparation

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

2. Replace Oxygen Sensors

• Tools Required: O2 sensor socket, wrench set, torque wrench
• Remove the upstream (pre-catalytic) O2 sensor using the O2 sensor socket.
  • Disconnect the electrical connector.
  • Install the new sensor and torque it to the manufacturer’s specifications (typically around 30 lb-ft).
• Repeat the process for the downstream (post-catalytic) O2 sensor.
• Reconnect the battery after replacing the sensors.

3. Inspect and Replace Catalytic Converter (if necessary)

• Tools Required: Socket set, jack and jack stands, cutting tool (if needed), exhaust gasket
• Lift the vehicle using a jack and secure it with jack stands.
• Remove the exhaust pipe bolts connecting the catalytic converter to the exhaust system.
• Inspect the catalytic converter for blockage or physical damage.
• If replacement is needed, install the new catalytic converter with a new gasket, ensuring all bolts are torqued to manufacturer specifications.
• Reinstall any removed exhaust components.

4. Clear Codes and Test

• Use the OBD-II scanner to clear the P0420 code from the vehicle’s computer.
• Start the engine and allow it to reach operating temperature.
• Take the vehicle for a test drive to verify that the check engine light does not reappear.