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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to prevent any electrical shorts.
• Allow the engine to cool before starting work.

2. Inspect and Replace Oxygen Sensors

• Sub-steps:
  1. Identify the location of the upstream and downstream oxygen sensors (usually before and after the catalytic converter).
  2. Unplug the electrical connectors from the sensors.
  3. Use an oxygen sensor socket or wrench to remove the sensors from the exhaust manifold and catalytic converter.
  4. Install the new oxygen sensors (ensure to apply anti-seize compound on the threads).
  5. Torque the sensors to the manufacturer’s specifications (typically around 30-40 lb-ft).

3. Inspect and Replace Catalytic Converter (if necessary)

• Sub-steps:
  1. Disconnect the exhaust pipes from the catalytic converter by removing the bolts or nuts.
  2. Remove any heat shields if applicable.
  3. Support the catalytic converter and remove it from its mounting brackets.
  4. Install the new catalytic converter, ensuring proper alignment with exhaust pipes.
  5. Reattach all bolts/nuts and torque them to the manufacturer’s specifications (usually around 25-30 lb-ft).
  6. Reinstall any heat shields.

4. Final Checks

• Sub-steps:
  1. Reconnect the battery.
  2. Start the engine and allow it to reach operating temperature.
  3. Monitor for any exhaust leaks around the catalytic converter and sensors.