how to resolve a P0420 code in my Honda Pilot Third Generation (2016-present)

Solution

1. Preparation

• Gather all necessary tools and parts.
• Ensure the vehicle is securely parked on a level surface with the engine off and cool.
• Disconnect the negative battery terminal.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, torque wrench
• Remove the downstream oxygen sensor using the O2 sensor socket.
• Inspect the sensor for signs of contamination or damage.
• If faulty, replace it with a new sensor, tightening it to the manufacturer’s specified torque.
• Reconnect the electrical connector.

3. Check and Replace the Catalytic Converter (if necessary)

• Tools Required: Socket set, exhaust pipe cutter, gaskets
• Remove the exhaust pipes connected to the catalytic converter using a socket set.
• Inspect the catalytic converter for any physical damage or signs of clogging.
• If replacement is needed, install a new catalytic converter using new gaskets, ensuring proper alignment and tightening to specifications.

4. Clear the Codes

• Reconnect the negative battery terminal.
• Use the OBD-II scanner to clear the P0420 code from the vehicle’s computer.

5. Test Drive

• Start the vehicle and allow it to reach normal operating temperature.
• Drive the vehicle under various conditions to ensure the check engine light does not reappear.