how to fix the P0420 code in my Genesis G70 IG (2017-2023)?

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Ensure the vehicle is on a flat surface and secure it with wheel chocks.

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. Use an oxygen sensor socket to remove the sensors from the exhaust manifold and catalytic converter.
  4. Install the new oxygen sensors by reversing the removal process, ensuring they are properly torqued (typically 30 lb-ft).
  5. Reconnect the electrical connectors to the new sensors.

3. Inspect and Replace Catalytic Converter

• Sub-steps:
  1. If the oxygen sensors were not the issue, locate the catalytic converter in the exhaust system.
  2. Check for any physical damage; if damaged, proceed to replace it.
  3. Remove the exhaust bolts/nuts securing the catalytic converter using a socket set.
  4. Carefully remove the old catalytic converter from the exhaust system.
  5. Install the new catalytic converter, ensuring proper alignment and secure it with the bolts/nuts to the manufacturer's torque specifications (generally 30-40 lb-ft).
  6. Reconnect any exhaust hangers that were disconnected during removal.

4. Clear Codes and Test

• Sub-steps:
  1. Reconnect the negative battery terminal.
  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 that the check engine light does not reappear and performance is restored.