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

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the battery to prevent any electrical issues while working on the vehicle.
• Allow the engine to cool completely before starting work.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, wrench set, multimeter.
• Remove the upstream (pre-catalytic) oxygen sensor using the O2 sensor socket.
• Inspect the sensor for damage or contamination. If faulty, replace with a new sensor.
• Repeat the process for the downstream (post-catalytic) oxygen sensor.
• Reconnect the battery and clear the codes using an OBD-II scanner.

3. Inspect and Replace Catalytic Converter

• Tools Required: Socket set, torque wrench, cutting tool (if necessary).
• Raise the vehicle securely on jack stands.
• Inspect the catalytic converter for physical damage or clogging. If damaged, proceed to replace it.
• Remove the exhaust pipes connected to the catalytic converter using a socket set.
• Install the new catalytic converter, ensuring all gaskets are in place.
• Torque all bolts to manufacturer specifications and reconnect any sensors.

4. Final System Check

• Start the engine and let it idle for a few minutes.
• Conduct a visual inspection for exhaust leaks.
• Use the OBD-II scanner to ensure the P0420 code does not return.