how to fix P0420 code in Tesla Model S Plaid/Refresh (2021-present)

Learn how to diagnose and fix P0420 catalytic converter efficiency issue in Tesla Model S Plaid. Step-by-step guide with diagnostic procedures and repair instructions.

Solution

1. Preparation

• Tools Required: OBD-II scanner, infrared thermometer, multimeter, socket set, jack and jack stands.
• Disconnect the 12V battery to ensure safety before working on the vehicle.
• Ensure the vehicle is on a level surface and secure it with jack stands.

2. Inspect and Replace Oxygen Sensors

• Sub-steps:
  1. Locate the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
  2. Disconnect the wiring connectors from both sensors.
  3. Use a socket set to remove the sensors from the exhaust system.
  4. Install new oxygen sensors, tightening them to the manufacturer's specifications (usually around 30 ft-lbs).
  5. Reconnect the wiring connectors securely.

3. Inspect and Replace the Catalytic Converter

• Sub-steps:
  1. Locate the catalytic converter in the exhaust system.
  2. Disconnect any associated sensors or fittings in the area.
  3. Use a socket set to unbolt the catalytic converter from the exhaust piping.
  4. Carefully remove the old catalytic converter and replace it with a new unit, ensuring proper alignment.
  5. Torque the bolts to the manufacturer's specifications (typically around 25 ft-lbs).
  6. Reconnect any sensors or fittings that were disconnected during removal.

4. Clear Codes and Test Drive

• Sub-steps:
  1. Reconnect the vehicle battery.
  2. Use the OBD-II scanner to clear any codes present in the ECM.
  3. Start the vehicle and allow it to reach operating temperature.
  4. Take the vehicle for a test drive to monitor performance and emissions.