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

Solution

1. Preparation

• Tools Required: OBD-II scanner, multimeter, socket set, torque wrench, jack and jack stands.
• Disconnect the battery to ensure safety during repairs.

2. Inspect and Replace Oxygen Sensors

1. Locate the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
2. Using a socket wrench, carefully disconnect the electrical connectors from both oxygen sensors.
3. Unscrew the sensors from their respective locations using the appropriate socket.
4. Install new oxygen sensors by threading them into their respective positions, ensuring they are tightened to the manufacturer's torque specification (typically around 30 lb-ft).
5. Reconnect the electrical connectors to the sensors.

3. Examine and Replace Catalytic Converter (if necessary)

1. Inspect the catalytic converter for any physical signs of damage or blockages.
2. If replacement is needed, use the socket set to remove the bolts securing the catalytic converter to the exhaust manifold and the exhaust pipe.
3. Remove the old catalytic converter from the vehicle.
4. Install the new catalytic converter and secure it using the original bolts, tightening to the specified torque (usually around 25 lb-ft).
5. Reconnect any oxygen sensors that were removed during the catalytic converter replacement.

4. Clear Codes and Test Drive

1. Reconnect the battery.
2. Use the OBD-II scanner to clear the P0420 code from the vehicle’s computer.
3. Start the engine and perform a test drive to ensure all systems are functioning correctly and the check engine light does not reappear.