how to diagnose 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

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a flat surface and turn off the ignition.
• Disconnect the battery to prevent electrical issues during the repair.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, torque wrench, penetrating oil.
• Remove the oxygen sensors from the exhaust system using the O2 sensor socket.
• Inspect the sensors for carbon buildup or damage; clean or replace as necessary.
• Install the new or cleaned sensors, tightening to the manufacturer’s specified torque value.

3. Replace Catalytic Converter (if necessary)

• Tools Required: Wrench set, jack stands, exhaust pipe cutter (if needed).
• Raise the vehicle using jack stands for access to the exhaust system.
• Disconnect the exhaust pipes from the catalytic converter, using the wrench to remove any bolts or clamps.
• Cut the exhaust pipe if it is welded to the catalytic converter, ensuring to leave enough length for the new connection.
• Install the new catalytic converter, ensuring proper orientation and alignment.
• Reconnect the exhaust pipes and secure with bolts/clamps to the manufacturer’s torque specifications.

4. Clear Codes and Test

• Reconnect the vehicle's battery.
• Use the OBD-II scanner to clear the P0420 code from the computer.
• Take the vehicle for a test drive to ensure that the problem has been resolved and monitor for any reoccurrence of the P0420 code.