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

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the battery to prevent any electrical shorts while working on the exhaust system.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, wrench set, multimeter.
• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors in the exhaust system.
  2. Disconnect the electrical connectors from the oxygen sensors.
  3. Use the O2 sensor socket to remove the faulty sensors.
  4. Install new oxygen sensors in their respective positions, ensuring they are tightened to the manufacturer’s specifications (typically around 30 ft-lbs).
  5. Reconnect the electrical connectors to the sensors.

3. Inspect and Replace Catalytic Converter (if necessary)

• Tools Required: Socket set, torque wrench, exhaust hanger tool.
• Sub-steps:
  1. If the catalytic converter is faulty, support the exhaust system with jack stands.
  2. Remove any heat shields or components obstructing access to the catalytic converter.
  3. Disconnect the exhaust pipes from the catalytic converter by removing the bolts using a socket set.
  4. Carefully remove the catalytic converter from its mounting brackets.
  5. Install the new catalytic converter, ensuring that it is aligned properly with the exhaust system.
  6. Torque the bolts to the manufacturer’s specifications (typically around 25-30 ft-lbs).
  7. Reinstall any heat shields or components that were removed.

4. Final Checks and Battery Reconnection

• Sub-steps:
  1. Reconnect the battery terminals.
  2. Start the engine and let it idle to check for any exhaust leaks or abnormal sounds.
  3. Use the OBD-II scanner to clear any stored codes.