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

Solution

1. Preparation

• Gather tools and parts.
• Disconnect the negative battery terminal to ensure safety.
• Allow the vehicle to cool before working on the exhaust system.

2. Inspect and Replace Oxygen Sensors

1. Locate the Oxygen Sensors: Identify the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
2. Disconnect the Sensors: Unplug the electrical connectors from both oxygen sensors.
3. Remove the Sensors: Use an O2 sensor socket to unscrew the sensors from the exhaust manifold and catalytic converter.
4. Install New Sensors: Apply anti-seize compound on the threads of the new sensors and install them in the same locations. Tighten to the manufacturer's specifications (typically around 30 lb-ft).
5. Reconnect Electrical Connectors: Ensure the connectors are securely attached.

3. Inspect and Replace the Catalytic Converter

1. Remove Exhaust Components: If the catalytic converter needs replacement, locate the mounting bolts and remove any brackets or hangers.
2. Unbolt the Catalytic Converter: Use a socket and ratchet to remove the bolts securing the catalytic converter to the exhaust system.
3. Install New Catalytic Converter: Position the new catalytic converter in place, aligning it with the exhaust system. Use new gaskets if necessary.
4. Secure the Converter: Tighten the bolts to the specified torque (usually around 40 lb-ft).
5. Reconnect Any Removed Components: Reattach hangers and brackets as needed.

4. Reconnect Battery and Clear Codes

1. Reconnect the Battery: Attach the negative battery terminal.
2. Clear Error Codes: Use an OBD-II scanner to reset the check engine light and clear any stored codes.