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

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Replace Oxygen Sensors

• Tools Required:

  • O2 sensor socket
  • Torque wrench
  • Penetrating oil (if necessary)

• Sub-steps:

  1. Locate the upstream and downstream oxygen sensors on the exhaust manifold and catalytic converter.
  2. Spray penetrating oil on the sensor threads if they are rusted.
  3. Remove the upstream oxygen sensor using an O2 sensor socket.
  4. Install the new upstream oxygen sensor and torque to the manufacturer's specifications (usually around 30 ft-lbs).
  5. Repeat the removal and installation for the downstream oxygen sensor.

3. Inspect and Replace Catalytic Converter

• Tools Required:

  • Socket set
  • Torque wrench
  • Gasket scraper
  • New gaskets

• Sub-steps:

  1. Remove any heat shields covering the catalytic converter, if present.
  2. Disconnect the catalytic converter from the exhaust system by unscrewing the bolts at both ends.
  3. Inspect the old catalytic converter for internal damage or clogging.
  4. Clean the mating surfaces of the exhaust pipes with a gasket scraper.
  5. Install the new catalytic converter with new gaskets, ensuring proper alignment.
  6. Torque the bolts to the manufacturer's specifications.

4. Reconnect Battery and Clear Codes

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