how to fix P0420 code on my Honda Pilot YF3 (2016-2022)

Solution

1. Preparation

• Gather tools and parts required for repair.
• Disconnect the vehicle battery to prevent electrical issues.
• Allow the engine to cool before working on the exhaust system.

2. Inspect and Clean Oxygen Sensors

• Remove the upstream and downstream oxygen sensors using an O2 sensor socket.
• Inspect the sensors for contamination or damage; replace if necessary.
• Clean the sensor threads and the area around the sensor ports.
• Reinstall the sensors and torque them to manufacturer specifications (usually around 30 lb-ft).

3. Replace the Catalytic Converter (if necessary)

• If the catalytic converter is confirmed faulty, remove it by unbolting the flange connections using a socket set.
• Carefully detach any heat shields or brackets securing the converter.
• Install the new catalytic converter, ensuring proper alignment with exhaust flanges.
• Torque the bolts to the manufacturer's specifications (typically around 40 lb-ft).
• Reattach any heat shields or brackets.

4. Reconnect Battery and Clear Codes

• Reconnect the vehicle battery.
• Use the OBD-II scanner to clear the P0420 code from the ECM.
• Start the engine and let it idle for a few minutes.