how to fix P0420 code Honda Accord 10th Generation (2018-2022)

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the negative battery terminal to prevent any electrical shorts.
• Allow the vehicle to cool down before working on the exhaust system.

2. Inspect and Replace Oxygen Sensors

1. Locate Oxygen Sensors: Identify the pre-catalytic and post-catalytic oxygen sensors on the exhaust system.
2. Remove Connectors: Carefully disconnect the electrical connectors for both sensors.
3. Remove Sensors: Use an oxygen sensor socket to unscrew and remove the sensors from their respective locations.
4. Install New Sensors: Apply anti-seize compound to the threads of the new sensors, then install and torque to manufacturer specifications (typically around 30 lb-ft).
5. Reconnect Electrical Connectors: Ensure that the connectors are securely attached.

3. Inspect and Replace Catalytic Converter (if necessary)

1. Exhaust Inspection: Check for any physical damage or blockages in the catalytic converter.
2. Remove Exhaust Flanges: Use a socket set to loosen and remove the bolts securing the catalytic converter to the exhaust system.
3. Remove Old Catalytic Converter: Carefully remove the catalytic converter from the exhaust system.
4. Install New Catalytic Converter: Position the new catalytic converter in place, ensuring proper alignment with exhaust pipes.
5. Secure with Bolts: Reattach the exhaust flanges and torque bolts to manufacturer specifications.

4. Reconnect Battery and Clear Codes

1. Reconnect Battery: Reattach the negative battery terminal securely.
2. Clear Error Codes: Use the OBD-II scanner to clear the P0420 code from the vehicle’s computer.
3. Test Drive: Perform a test drive to ensure the vehicle operates normally.