how do I fix a P0420 code in my Genesis G70 IG (2017-2023)

Solution

1. Preparation

• Gather tools and parts.
• Disconnect the battery to ensure safety while working on electrical components.

2. Inspect and Replace Oxygen Sensors

1. Remove the upstream oxygen sensor:

   • Tools: O2 sensor socket, ratchet.
   • Disconnect the electrical connector and use the O2 sensor socket to unscrew the sensor from the exhaust manifold.

2. Replace the upstream oxygen sensor:

   • Install the new sensor, ensuring it is properly threaded and tighten to the manufacturer's specification (typically around 30 ft-lbs).
   • Reconnect the electrical connector.

3. Remove the downstream oxygen sensor:

   • Repeat the steps above for the downstream sensor located after the catalytic converter.

4. Replace the downstream oxygen sensor:

   • Install the new sensor in the same manner as the upstream sensor and reconnect its electrical connector.

3. Inspect and Replace the Catalytic Converter (if necessary)

1. Check for blockage:
   • If the temperature test indicated blockage, or if previous steps did not resolve the code, replace the catalytic converter.
2. Remove the catalytic converter:
   • Tools: Socket set, ratchet, exhaust hanger removal tool.
   • Disconnect the exhaust pipes from both ends of the converter and remove any brackets or hangers.
3. Install the new catalytic converter:
   • Position the new catalytic converter and secure it to the exhaust system using new gaskets and bolts as needed. Torque the bolts to specifications (usually around 25-30 ft-lbs).
4. Reconnect any exhaust hangers and brackets as necessary.

4. Reconnect Battery and Clear Codes

• Reconnect the battery and clear the P0420 code using the OBD-II scanner.