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

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the battery to ensure safety during repair.
• Allow the exhaust system to cool before starting any work.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, wrench set, torque wrench
• Remove the upstream (pre-catalytic) oxygen sensor using the O2 sensor socket.
• Check the sensor for signs of damage or contamination.
• If faulty, replace it with a new sensor, tightening it to the manufacturer's specified torque (typically around 30 lb-ft).
• Repeat this process for the downstream (post-catalytic) oxygen sensor if also deemed faulty.

3. Inspect and Replace Catalytic Converter

• Tools Required: Socket set, exhaust pipe cutter (if necessary), jack stands
• Raise the vehicle and secure it on jack stands.
• Remove any heat shields or brackets securing the catalytic converter.
• Detach the catalytic converter from the exhaust system, taking care to note how it connects.
• Inspect for any excessive buildup or physical damage; if defective, replace it with a new catalytic converter.
• Reinstall the new catalytic converter, ensuring all connections are secure and bolts are tightened to the specified torque.

4. Clear Codes and Test Drive

• Reconnect the battery, start the engine, and use the OBD-II scanner to clear the P0420 code.
• Take the vehicle for a test drive under various conditions to ensure proper operation.
• Monitor the system for any reappearance of the P0420 code.