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

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

Solution

1. Preparation

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

2. Inspect and Replace Oxygen Sensors

• Locate the upstream oxygen sensor connected to the exhaust manifold and the downstream sensor after the catalytic converter.
• Tools Required: O2 sensor socket, ratchet, torque wrench.
• Sub-steps:
  1. Disconnect the electrical connectors from both oxygen sensors.
  2. Using the O2 sensor socket, unscrew the upstream sensor and replace it with a new one.
  3. Torque the new sensor to the manufacturer’s specifications (typically around 30 lb-ft).
  4. Repeat the process for the downstream oxygen sensor.

3. Inspect and Replace Catalytic Converter (if necessary)

• Check the catalytic converter for any signs of blockage or damage.
• Tools Required: Socket set, jack and jack stands, exhaust gasket, torque wrench.
• Sub-steps:
  1. Remove any heat shields covering the catalytic converter.
  2. Using a socket set, unbolt the catalytic converter from the exhaust system.
  3. Remove the old catalytic converter and clean the mating surfaces.
  4. Install the new catalytic converter with a new gasket, tightening bolts to the specified torque.
  5. Reattach any heat shields removed during the process.

4. Reset the Engine Control Module (ECM)

• After repairs, reconnect the negative battery terminal.
• Start the vehicle and allow it to reach operating temperature.
• Use the OBD-II scanner to clear the P0420 code from the ECM.