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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to prevent electrical shock.
• Raise the vehicle using jack stands for safety.

2. Inspect and Replace Oxygen Sensors (if faulty)

1. Locate the upstream and downstream oxygen sensors on the exhaust system.
2. Unplug the electrical connectors from both sensors.
3. Use an oxygen sensor socket to remove the sensors from their ports.
4. Install the new oxygen sensors, ensuring they are properly threaded and torqued to manufacturer specifications (typically around 30 lb-ft).
5. Reconnect the electrical connectors to both sensors.

3. Inspect and Replace Catalytic Converter (if necessary)

1. Remove the exhaust system components (if applicable) to gain access to the catalytic converter.
2. Unbolt the catalytic converter from the exhaust manifold and the mid-pipe, noting the orientation of gaskets.
3. Remove the old catalytic converter and install the new one, ensuring proper alignment.
4. Torque the bolts to the manufacturer's specifications (usually around 20-25 lb-ft).
5. Reinstall any exhaust components that were removed.

4. Clear Codes and Test Drive

1. Reconnect the battery.
2. Use the OBD-II scanner to clear the P0420 code.
3. Test drive the vehicle for a minimum of 20 miles to ensure the code does not reappear.