how to fix P0420 code on 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.
• Park the vehicle on a level surface and engage the parking brake.
• Disconnect the battery for safety.

2. Inspect and Replace Oxygen Sensors

1. Locate the Oxygen Sensors:

   • Identify the upstream (pre-catalytic converter) and downstream (post-catalytic converter) oxygen sensors.

2. Remove the Oxygen Sensors:

   • Use an oxygen sensor socket to unscrew the sensors from their respective locations.
   • Disconnect the electrical connectors carefully to avoid damage.

3. Install New Oxygen Sensors:

   • Apply anti-seize compound on the threads of the new sensors.
   • Install the new sensors by hand and tighten to the manufacturer's specifications (typically around 30-40 lb-ft).
   • Reconnect the electrical connectors.

3. Inspect and Replace the Catalytic Converter (if necessary)

1. Remove Exhaust Components:

   • Unbolt any exhaust components connected to the catalytic converter, taking care not to damage any gaskets.
   • Support the exhaust with a jack stand if necessary.

2. Remove the Catalytic Converter:

   • Unbolt the catalytic converter from its mounting points.
   • Carefully remove it from the vehicle.

3. Install New Catalytic Converter:

   • Position the new catalytic converter and bolt it in place, ensuring all gaskets are properly seated.
   • Reattach any exhaust components that were removed.

4. Reconnect Battery and Clear Codes

1. Reconnect the Battery:

   • Reconnect the negative battery terminal and ensure it is tight.

2. Clear Error Codes:

   • Use the OBD-II scanner to erase the P0420 code and any related diagnostic trouble codes.

5. Test Drive

• Take the vehicle for a test drive to ensure the check engine light does not reappear and monitor performance.