how to fix Tesla Model S Plaid/Refresh (2021-present) check engine light P0420

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

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

2. Inspect and Replace Oxygen Sensors (if necessary)

• Tools Required: O2 sensor socket, ratchet, and extension.
• Remove the oxygen sensors from the exhaust system:
  • Locate the upstream and downstream O2 sensors.
  • Use the O2 sensor socket to unscrew the sensors from their respective bungs.
• Install new oxygen sensors:
  • Apply anti-seize compound to the threads of the new sensors.
  • Screw in the new O2 sensors until snug, then tighten to manufacturer's specifications (usually around 30 ft-lbs).

3. Inspect and Replace Catalytic Converter (if necessary)

• Tools Required: Socket set, torque wrench, exhaust gasket.
• Remove the catalytic converter:
  • Disconnect any brackets or mounts securing the catalytic converter.
  • Unbolt the catalytic converter from the exhaust pipes.
• Install the new catalytic converter:
  • Ensure that the exhaust flanges are clean and free of debris.
  • Place a new exhaust gasket on the flange.
  • Bolt the new catalytic converter into place, tightening bolts to the specified torque (typically around 20-25 ft-lbs).

4. Reconnect Battery

• Reconnect the negative battery terminal securely.

5. Clear Codes and Test

• Use the OBD-II scanner to clear the P0420 code.
• Start the vehicle and allow it to idle for a few minutes.
• Take the vehicle for a short test drive to ensure that the Check Engine Light does not re-illuminate.