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

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a level surface.
• Disconnect the battery to prevent electrical issues.

2. Inspect and Repair Exhaust Leaks

• Sub-steps:
  • Visually inspect the exhaust manifold, pipes, and connections for leaks.
  • Use a smoke machine or soapy water to identify leaks.
  • If leaks are found, replace damaged components or use exhaust sealant as needed.

3. Replace Faulty Oxygen Sensors

• Sub-steps:
  • Locate and remove the upstream and downstream oxygen sensors.
  • Install new oxygen sensors according to specifications.
  • Torque the sensors to the manufacturer’s recommended values (typically around 30 ft-lbs).

4. Replace Catalytic Converter (if necessary)

• Sub-steps:
  • Remove the exhaust pipes connected to the catalytic converter using a socket set.
  • Detach the old catalytic converter from the exhaust system.
  • Install the new catalytic converter, ensuring all gaskets are properly seated.
  • Reattach the exhaust pipes and torque to specifications.

5. Reconnect Battery and Clear Codes

• Sub-steps:
  • Reconnect the battery terminals.
  • Use an OBD-II scanner to clear the P0420 code.

6. Test Drive

• Drive the vehicle for a minimum of 20 minutes to allow the ECU to monitor the new components and ensure the code does not reappear.