my Genesis G70 IG (2017-2023) has a check engine light and code P0420, what does that mean?

Solution

1. Preparation

• Ensure the vehicle is parked on a flat surface and the engine is cool.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Gather necessary tools and parts.

2. Inspect and Replace the Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench
• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors in the exhaust system.
  2. Disconnect the electrical connectors from both oxygen sensors.
  3. Using an O2 sensor socket, remove the upstream oxygen sensor.
  4. Install the new upstream oxygen sensor, tightening to the manufacturer’s specified torque (typically 30 lb-ft).
  5. Repeat the removal and installation for the downstream oxygen sensor if it is also faulty.

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

• Tools Required: Socket set, jack stands, exhaust gasket
• Sub-steps:
  1. Raise the vehicle using jack stands for access to the exhaust system.
  2. Disconnect the exhaust pipe from the catalytic converter by removing the bolts and/or clamps.
  3. Remove any heat shields or brackets securing the catalytic converter.
  4. Remove the catalytic converter from the mounting points.
  5. Install the new catalytic converter, ensuring all gaskets are in place, and secure it with bolts to the specified torque.
  6. Reattach the exhaust pipe and any heat shields or brackets.

4. Reconnect Battery and Clear Codes

• Reconnect the negative battery terminal.
• Use the OBD-II scanner to clear the check engine light and stored codes.