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

Solution

1. Preparation

• Gather tools and parts required.
• Disconnect the battery to prevent electrical issues.
• Allow the engine to cool down before working on exhaust components.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, torque wrench.
• Disconnect the electrical connectors from the upstream and downstream oxygen sensors.
• Use the O2 sensor socket to remove the sensors from the exhaust system.
• Install new oxygen sensors and torque them to manufacturer specifications (typically around 30 lb-ft).
• Reconnect the electrical connectors.

3. Inspect and Replace the Catalytic Converter

• Tools Required: Socket set, gasket scraper, torque wrench.
• Locate the catalytic converter in the exhaust system.
• Remove any heat shields or brackets securing the converter.
• Disconnect the exhaust pipes from the catalytic converter (may require cutting if rusted).
• Use a gasket scraper to clean the mating surfaces.
• Install the new catalytic converter, ensuring gaskets are in place.
• Torque the exhaust bolts to the manufacturer's specifications.

4. Clear Error Codes

• Reconnect the battery.
• Use the OBD-II scanner to clear the P0420 code from the ECU.

5. Test Drive the Vehicle

• Drive the vehicle under various conditions to ensure the check engine light does not reappear.