how to fix P0420 code on 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 necessary tools and parts.
• Ensure the vehicle is parked on a flat surface and the engine is cool.
• Disconnect the negative battery terminal to prevent any electrical shorts.

2. Inspect and Replace Oxygen Sensors

1. Locate the Oxygen Sensors:

   • Find the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors in the exhaust system.

2. Remove the Oxygen Sensors:

   • Use an oxygen sensor socket to unscrew the sensors.
   • Disconnect the electrical connectors carefully.

3. Install New Sensors:

   • Apply anti-seize compound on the threads of the new oxygen sensors.
   • Install the new sensors securely and connect the electrical connectors.

3. Inspect and Replace Catalytic Converter (if required)

1. Check Catalytic Converter Condition:

   • If the oxygen sensors are functioning properly, inspect the catalytic converter for physical damage or clogging.

2. Remove the Catalytic Converter:

   • Use a wrench or socket set to detach the catalytic converter from the exhaust system.
   • Ensure to unbolt any brackets and disconnect any heat shields if necessary.

3. Install New Catalytic Converter:

   • Position the new catalytic converter in place and secure with bolts.
   • Reattach any heat shields and brackets removed during the process.

4. Reconnect Battery and Clear Codes

1. Reconnect the Negative Battery Terminal:

   • Ensure all tools are removed from the engine bay before reconnecting.

2. Clear the Diagnostic Codes:

   • Use the OBD-II scanner to clear the P0420 code from the vehicle's memory.

3. Test Drive the Vehicle:

   • Conduct a road test to ensure the check engine light does not reappear and that performance is restored.