how to fix P0420 code on Honda Accord Eleventh Generation (2023-present)?

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to ensure safety while working on electrical components.

2. Inspect and Replace Oxygen Sensors

1. Locate the upstream and downstream oxygen sensors.
2. Remove the oxygen sensor connectors carefully.
3. Using an oxygen sensor socket, remove the sensors from the exhaust system.
4. Install new oxygen sensors, tightening them to the manufacturer's specified torque (usually around 30 lb-ft).
5. Reconnect the oxygen sensor electrical connectors.

3. Check and Replace the Catalytic Converter

1. Inspect the catalytic converter for physical damage or signs of clogging.
2. If replacement is necessary, loosen the exhaust clamps or bolts securing the catalytic converter to the exhaust system.
3. Remove the catalytic converter from the vehicle.
4. Install the new catalytic converter, ensuring proper alignment and sealing.
5. Tighten the exhaust clamps or bolts to the manufacturer’s specifications.

4. Reconnect Battery and Clear Codes

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