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

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the battery to avoid electrical shorts during the repair.

2. Inspect and Replace Oxygen Sensors

1. Remove the upstream oxygen sensor:
   • Locate the upstream oxygen sensor near the exhaust manifold.
   • Use an oxygen sensor socket to unscrew and remove the sensor.
2. Replace the sensor:
   • Apply anti-seize compound to the threads of the new oxygen sensor.
   • Install the new sensor and torque it to the manufacturer's specifications (typically around 30 lb-ft).
3. Repeat for the downstream oxygen sensor if needed:
   • Follow the same procedure for the downstream sensor located before the catalytic converter.

3. Inspect and Clean or Replace the Catalytic Converter

1. Inspect the catalytic converter:
   • Visually inspect for physical damage or signs of clogging.
   • Use a flashlight to check for any internal damage through the oxygen sensor ports.
2. Clean the catalytic converter:
   • If it’s clogged but not damaged, consider using a catalytic converter cleaner additive in the fuel system.
3. Replace the catalytic converter (if necessary):
   • Disconnect the exhaust pipes from the catalytic converter using a socket set.
   • Remove any hanging brackets and bolts.
   • Install the new catalytic converter, ensuring proper alignment and securing with bolts to the specified torque.

4. Reconnect Battery and Clear Codes

1. Reconnect the battery terminals and ensure they are tight.
2. Use the OBD-II scanner to clear the P0420 code.
3. Perform a test drive to confirm that the check engine light does not return.