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 tools and parts.
• Disconnect the vehicle's battery to ensure safety while working on the electrical components.

2. Inspect and Replace Oxygen Sensors

1. Locate the upstream and downstream oxygen sensors connected to the catalytic converter.
2. Use an O2 sensor socket to remove the sensors.
3. Inspect the sensors for any signs of damage or contamination.
4. If faulty, replace the sensors with new ones (ensure compatibility with the Model S).
5. Reconnect the sensors securely.

3. Inspect and Repair Exhaust System

1. Visually inspect the exhaust system for any signs of cracks, rust, or loose connections.
2. Use a wrench to tighten any loose bolts or connections.
3. If any components are damaged, replace them as necessary (including gaskets and clamps).

4. Test Catalytic Converter

1. Use a backpressure gauge to measure the pressure before and after the catalytic converter.
2. A pressure reading above manufacturer specifications indicates a clogged catalytic converter.
3. If clogged, remove the catalytic converter by unbolting it from the exhaust system.
4. Replace it with a new catalytic converter designed for the Model S Plaid.

5. Reconnect Battery and Clear Codes

1. Reconnect the vehicle's battery.
2. Use the OBD-II scanner to clear the error codes from the vehicle's computer.
3. Start the engine and allow it to reach operating temperature.