how to fix P0420 code on Honda Accord 9th Generation (2013-2017)

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Disconnect the battery to prevent any electrical shorts.
• Allow the vehicle to cool if it has been running recently.

2. Inspect and Replace Oxygen Sensors (if necessary)

• Tools Required: O2 sensor socket, ratchet, torque wrench
• Remove the upstream oxygen sensor (located before the catalytic converter) by using the O2 sensor socket.
• Inspect the sensor for any damage or contamination.
• If the sensor is faulty, replace it with a new one, and torque it to the manufacturer's specification (usually around 30 ft-lbs).
• Repeat the process for the downstream oxygen sensor if it is also suspected to be faulty.

3. Inspect and Replace Catalytic Converter (if necessary)

• Tools Required: Socket set, torque wrench, exhaust hanger removal tool
• Raise the vehicle securely on jack stands.
• Remove the exhaust pipe connected to the catalytic converter by unbolting the flanges and using the exhaust hanger removal tool.
• Inspect the catalytic converter for any signs of damage or blockage. If necessary, unbolt and remove the catalytic converter.
• Install the new catalytic converter by reversing the removal steps, ensuring all gaskets are replaced and torquing bolts to specifications (typically around 30 ft-lbs).

4. Clear Codes and Test Drive

• Reconnect the battery.
• Use the OBD-II scanner to clear the stored trouble codes.
• Start the engine and allow it to reach operating temperature.
• Conduct a test drive to monitor for any reoccurrence of the P0420 code.