what does code P0420 mean for my Honda Accord 9th Generation (2013-2017)?

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Allow the engine to cool down before working on the exhaust system.

2. Replace Faulty Oxygen Sensor

• Tools Required: O2 sensor socket, ratchet, torque wrench
• Remove the upstream oxygen sensor using the O2 sensor socket.
• Install the new oxygen sensor and torque it to the manufacturer’s specification (typically around 30 ft-lbs).
• Reconnect the electrical connector.

3. Inspect and Replace Catalytic Converter (if necessary)

• Tools Required: Socket set, jack and jack stands, exhaust hanger removal tool, torque wrench
• Raise the vehicle and support it securely with jack stands.
• Remove any bolts or clamps securing the catalytic converter to the exhaust system.
• Disconnect any exhaust hangers using the exhaust hanger removal tool.
• Remove the catalytic converter from the vehicle.
• Install the new catalytic converter by reversing the removal steps, ensuring all connections are tight and torqued to manufacturer specifications.

4. Clear Codes and Test Drive

• Reconnect the negative battery terminal.
• Use the OBD-II scanner to clear the P0420 code from the vehicle’s computer.
• Start the engine and allow it to reach operating temperature.
• Take the vehicle for a test drive to confirm that the check engine light does not reappear.