how to fix P0420 code in 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 all tools and parts needed.
• Ensure the vehicle is parked on a level surface and the parking brake is engaged.
• Disconnect the negative terminal of the battery to prevent electrical shorts.

2. Inspect and Replace Oxygen Sensors

• Sub-steps:
  1. Locate the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
  2. Use a socket wrench to unscrew the oxygen sensors from their respective locations.
  3. Inspect the sensors for damage or corrosion.
  4. Install new oxygen sensors, ensuring they are tightened to manufacturer specifications (typically 30 ft-lbs).
  5. Reconnect the battery terminal.

3. Examine and Replace Catalytic Converter (if necessary)

• Sub-steps:
  1. Remove the exhaust heat shield (if applicable) using a socket set.
  2. Disconnect the exhaust pipes from both ends of the catalytic converter.
  3. Unbolt the catalytic converter from the mounting brackets (typically requires a torque of 25-30 ft-lbs).
  4. Install the new catalytic converter, ensuring proper alignment.
  5. Reconnect the exhaust pipes and heat shield, ensuring all bolts are tightened to manufacturer specifications.

4. Clear Codes and Test Drive

• Sub-steps:
  1. Use the OBD-II scanner to clear the P0420 code from the vehicle's computer.
  2. Take the vehicle for a test drive for at least 20-30 minutes to monitor the performance and check if the check engine light returns.