how to fix P0420 code on my Genesis G70 IG (2017-2023)

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to avoid electrical issues.
• Allow the engine to cool before working on the exhaust system.

2. Inspect and Replace Oxygen Sensors (if faulty)

• Tools Required: O2 sensor socket, ratchet, torque wrench.
• Sub-steps:
  1. Locate the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
  2. Disconnect the electrical connectors from the sensors.
  3. Use the O2 sensor socket to remove the sensors from the exhaust manifold and catalytic converter.
  4. Install new sensors by screwing them in place and tightening to the manufacturer's specified torque (typically around 30 lb-ft).
  5. Reconnect the electrical connectors.

3. Inspect and Replace Catalytic Converter (if necessary)

• Tools Required: Socket set, torque wrench, exhaust gasket scraper.
• Sub-steps:
  1. Raise the vehicle securely on jack stands for access to the exhaust system.
  2. Remove the exhaust bolts connecting the catalytic converter to the exhaust manifold and the exhaust pipe.
  3. Carefully take out the old catalytic converter. If there is any gasket material, scrape it clean from the exhaust flanges.
  4. Install the new catalytic converter, ensuring proper alignment with exhaust pipes.
  5. Torque the bolts to the manufacturer's specifications, usually around 30-40 lb-ft.
  6. Reconnect any heat shields or mounts that were removed.

4. Reset the Engine Control Module (ECM)

• Tools Required: OBD-II scanner.
• Sub-steps:
  1. Reconnect the battery.
  2. Use the OBD-II scanner to erase the P0420 code from the ECM.
  3. Start the engine and allow it to reach operating temperature.