how to fix P0420 code in Honda Accord Eleventh Generation (2023-present)

Solution

1. Preparation

• Gather tools and parts needed for repair.
• Disconnect the battery before starting work.
• Ensure the vehicle is on a flat surface and secured with jack stands if elevated.

2. Inspect and Replace Oxygen Sensors

• Sub-steps:
  1. Locate the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
  2. Disconnect the electrical connectors from both sensors.
  3. Using a ratchet and O2 sensor socket, remove the sensors from the exhaust system.
  4. Install the new oxygen sensors, ensuring they are tightened to manufacturer specifications (usually around 30 lb-ft).
  5. Reconnect the electrical connectors.

3. Inspect and Replace the Catalytic Converter

• Sub-steps:
  1. Remove any heat shields or components obstructing access to the catalytic converter.
  2. Unbolt the catalytic converter from the exhaust system using a socket set (typically 14-18 lb-ft torque for bolts).
  3. Carefully remove the catalytic converter from its mounting.
  4. Install the new catalytic converter, ensuring proper alignment with the exhaust system.
  5. Tighten all bolts to the specified torque values.
  6. Reinstall any heat shields or components removed during the process.

4. Clear Codes and Test Drive

• Sub-steps:
  1. Reconnect the battery.
  2. Use the OBD-II scanner to clear the P0420 code from the system.
  3. Start the engine and let it idle for a few minutes, then take the vehicle for a test drive to ensure proper functionality.