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

• Tools Required: OBD-II scanner, socket set, torque wrench, exhaust gas analyzer.
• 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

• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors in the exhaust system.
  2. Unplug the electrical connectors from both sensors.
  3. Use a socket wrench to remove the sensors from their mounts.
  4. Install new oxygen sensors, ensuring they are torqued to the manufacturer's specifications (typically around 30 lb-ft).
  5. Reconnect the electrical connectors securely.

3. Inspect and Repair Exhaust System

• Sub-steps:
  1. Check for any visible exhaust leaks or damaged components.
  2. If leaks are found, replace gaskets or exhaust pipes as necessary.
  3. Tighten all exhaust connections to specification to ensure no air leaks.
  4. If the catalytic converter is damaged, it must be replaced.

4. Clear Codes and Test Drive

• Sub-steps:
  1. Reconnect the negative battery terminal.
  2. Use the OBD-II scanner to clear the P0420 code from the system.
  3. Start the vehicle and allow it to reach operating temperature.
  4. Perform a test drive to monitor vehicle performance and ensure the check engine light does not reappear.