how to fix the P0420 code on my Honda Accord Eleventh Generation (2023-present)

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, jack and jack stands, safety glasses, gloves
• Ensure the vehicle is parked on a flat surface and the engine is cool.
• Disconnect the battery to prevent electrical shorts.

2. Inspect and Replace Oxygen Sensors

• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors.
  2. Disconnect the electrical connectors from both sensors.
  3. Use a socket wrench to remove the sensors from their locations.
  4. Install new oxygen sensors (ensure they are compatible with the 2023 Honda Accord).
  5. Torque the sensors to the manufacturer's specifications (typically around 30-40 lb-ft).
  6. Reconnect the electrical connectors.

3. Inspect and Replace the Catalytic Converter

• Sub-steps:
  1. Raise the vehicle using a jack and secure it with jack stands.
  2. Locate the catalytic converter and check for damage or blockages.
  3. Use a socket set to remove the bolts securing the catalytic converter to the exhaust system.
  4. Carefully remove the catalytic converter from its position.
  5. Install the new catalytic converter, ensuring proper alignment with the exhaust pipes.
  6. Torque the bolts to the manufacturer's specifications (refer to service manual for exact values).

4. Clear Codes and Test Drive

• Sub-steps:
  1. Reconnect the battery.
  2. Use the OBD-II scanner to clear the P0420 code.
  3. Start the engine and allow it to reach operating temperature.
  4. Take the vehicle for a test drive to ensure the check engine light does not reappear.