how to fix P0420 code on Honda Accord 9th Generation (2013-2017)

Solution

1. Preparation

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

2. Inspect and Replace Oxygen Sensors

1. Locate the upstream and downstream oxygen sensors on the exhaust system.
2. Remove the oxygen sensor connectors.
3. Use an oxygen sensor socket to unscrew and remove the old sensors.
4. Install new oxygen sensors by reversing the removal process. Ensure they are tightened to the manufacturer's specifications (typically around 30 Nm).
5. Reconnect the oxygen sensor connectors.

3. Inspect and Replace Catalytic Converter

1. If the oxygen sensors are functioning properly, inspect the catalytic converter.
2. Remove any heat shields or brackets holding the catalytic converter in place.
3. Use a socket set to remove the bolts securing the catalytic converter to the exhaust manifold and the exhaust pipe.
4. Carefully take out the old catalytic converter.
5. Install the new catalytic converter, ensuring proper alignment with the exhaust system. Torque the bolts to the manufacturer's specifications (typically around 40 Nm).
6. Reinstall any heat shields or brackets removed earlier.

4. Clear Error Codes

1. Reconnect the battery.
2. Use the OBD-II scanner to clear the P0420 code from the vehicle's computer.