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

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Ensure the vehicle is parked on a level surface and set the parking brake.
• Disconnect the battery to prevent electrical shorts.

2. Inspect and Replace Oxygen Sensors

1. Locate Sensors: Identify the upstream and downstream oxygen sensors in the exhaust system.
2. Disconnect Sensors: Unplug the electrical connectors from both sensors.
3. Remove Sensors: Use an oxygen sensor socket to remove the sensors from the exhaust pipes.
4. Install New Sensors: Apply anti-seize compound to the threads of the new sensors and install them into their respective positions.
5. Reconnect: Plug the electrical connectors back into the sensors.

3. Inspect and Replace Catalytic Converter (if necessary)

1. Remove Exhaust Components: If inspection shows the catalytic converter is faulty, remove any bolts or clamps securing the exhaust pipe to the catalytic converter using a socket set.
2. Support the Exhaust: Use a jack or a support stand to hold the exhaust while the catalytic converter is removed.
3. Remove Catalytic Converter: Carefully detach the catalytic converter from the exhaust system.
4. Install New Catalytic Converter: Position the new catalytic converter and secure it using the original bolts or clamps. Torque to manufacturer specifications (typically around 30-40 lb-ft).
5. Reassemble Exhaust: Reattach any exhaust components that were removed.

4. Final Checks

1. Reconnect Battery: Reconnect the battery terminals.
2. Clear Codes: Use the OBD-II scanner to clear the P0420 code.
3. Test Drive: Start the vehicle and take it for a test drive to check for any reoccurring codes and ensure proper operation.