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

Solution

1. Preparation

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

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, torque wrench
• Remove the upstream oxygen sensor using the O2 sensor socket.
• Inspect the sensor for any signs of damage or contamination.
• If necessary, replace the sensor with a new one. Torque the new sensor to the manufacturer’s specifications (typically around 30 ft-lbs).
• Repeat the process for the downstream oxygen sensor, if necessary.

3. Inspect and Replace Catalytic Converter

• Tools Required: Wrench set, jack stands, exhaust pipe cutter (if needed), gasket maker
• Lift the vehicle securely using jack stands.
• Inspect the catalytic converter for any physical damage or excessive rust.
• If replacement is needed, disconnect the exhaust pipes from the catalytic converter. Use an exhaust pipe cutter if necessary.
• Remove the old catalytic converter and clean the exhaust flanges.
• Install the new catalytic converter, ensuring to use new gaskets and torquing according to specifications.
• Reconnect the exhaust pipes.

4. Clear Error Codes and Test

• Reconnect the battery.
• Use the OBD-II scanner to clear the P0420 code from the system.
• Start the engine and allow it to reach operating temperature.
• Perform a test drive to ensure the check engine light does not reappear and that the vehicle operates smoothly.