how to fix P0420 code in Honda Civic 11th Generation (2022-Present)

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Allow the vehicle to cool down before proceeding with repairs.

2. Inspect and Clean Oxygen Sensors

• Remove the upstream and downstream oxygen sensors using a socket wrench.
• Inspect sensors for contamination or damage.
• Clean the sensors with an appropriate sensor-safe cleaner or replace if necessary.
• Reinstall the sensors and reconnect the wiring harness.

3. Examine the Catalytic Converter

• Raise the vehicle securely on jack stands.
• Visually inspect the catalytic converter for any dents, cracks, or signs of overheating.
• Use a flashlight to check the inlet and outlet for blockages.
• If damaged, proceed to replace the catalytic converter.

4. Replace Catalytic Converter (if necessary)

• Remove the exhaust pipes connected to the catalytic converter using a socket set.
• Unbolt the catalytic converter from its mounting points.
• Install the new catalytic converter in reverse order, ensuring proper alignment.
• Torque the bolts to manufacturer specifications (typically around 30-40 ft-lbs).

5. Reconnect and Test

• Reconnect the negative battery terminal.
• Start the engine and allow it to reach operating temperature.
• Use the OBD-II scanner to clear the P0420 code and check for reoccurrence.