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

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the negative terminal of the battery.
• Allow the engine to cool completely before starting work.

2. Inspect and Replace Oxygen Sensors

1. Remove the upstream (pre-catalytic converter) oxygen sensor using an O2 sensor socket.
2. Inspect the sensor for damage or contamination and replace if necessary.
3. Reinstall the new oxygen sensor and torque to manufacturer specifications (typically around 30 lb-ft).
4. Repeat the process for the downstream (post-catalytic converter) oxygen sensor if it shows signs of failure.

3. Inspect and Replace the Catalytic Converter

1. Raise the vehicle safely on jack stands and secure it.
2. Remove the exhaust pipes connected to the catalytic converter, using a socket set.
3. Inspect the catalytic converter for physical damage or clogging.
4. If replacement is necessary, remove the old catalytic converter and install the new one.
5. Torque all connections to manufacturer specifications and ensure proper sealing.

4. Clear Error Codes

1. Reconnect the negative battery terminal.
2. Use an OBD-II scanner to clear the stored P0420 code from the vehicle’s computer.
3. Start the engine and allow it to reach operating temperature.