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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the vehicle's battery to prevent electrical shorts.
• Ensure the vehicle is on a flat surface and securely lifted if needed.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, wrench set, torque wrench
• Remove the upstream (pre-catalytic) oxygen sensor using an O2 sensor socket.
• Inspect the sensor for damage; replace if faulty.
• Install the new sensor, torque to manufacturer specifications (usually around 30 lb-ft).
• Repeat for the downstream (post-catalytic) oxygen sensor if necessary.

3. Inspect and Replace Catalytic Converter

• Tools Required: Wrench set, exhaust pipe cutter, new gaskets, torque wrench
• Remove any exhaust hangers or clamps securing the catalytic converter.
• Cut the exhaust pipe at the designated points if necessary.
• Remove the old catalytic converter from the vehicle.
• Install the new catalytic converter with new gaskets, ensuring proper alignment.
• Reattach exhaust hangers and clamps, torque to manufacturer specifications.

4. Clear Codes and Test Drive

• Reconnect the battery.
• Use the OBD-II scanner to clear the P0420 code.
• Test drive the vehicle under various conditions to ensure that the check engine light does not reappear.