how to fix the code P0420 in my 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 the engine is cool.
• Disconnect the battery to prevent electrical shorts.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, torque wrench, multimeter.
• Remove the upstream and downstream oxygen sensors:
  1. Locate the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
  2. Use the O2 sensor socket to unscrew and remove the sensors.
• Test the sensors:
  1. Use a multimeter to check the resistance of the sensors against manufacturer specifications.
  2. Replace any faulty sensors with OEM parts.
• Install new oxygen sensors:
  1. Apply anti-seize compound to the threads of the new sensors.
  2. Install the new sensors and torque to manufacturer specifications.

3. Inspect and Replace Catalytic Converter (if necessary)

• Tools Required: Socket set, torque wrench, exhaust gasket.
• Remove the catalytic converter:
  1. Disconnect the exhaust pipes leading to and from the catalytic converter.
  2. Remove any mounting bolts or brackets holding the converter in place.
• Inspect the interior of the catalytic converter for blockages or damage.
• If replacement is needed:
  1. Install the new catalytic converter with new gaskets.
  2. Torque all bolts to manufacturer specifications.

4. Clear Codes and Test Drive

• Reconnect the battery and clear the P0420 code using an OBD-II scanner.
• Test drive the vehicle under various conditions to ensure that the check engine light does not reappear.