how to fix P0420 code on 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.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Ensure the vehicle is on a level surface and securely lifted if necessary.

2. Inspect and Replace Oxygen Sensors

• Step 1: Locate the upstream and downstream oxygen sensors.
• Step 2: Disconnect the wiring harness from each sensor.
• Step 3: Use an O2 sensor socket to remove the sensors.
• Step 4: Install new oxygen sensors by threading them into the exhaust system and tightening them to the manufacturer's torque specifications (typically around 30-45 lb-ft).
• Step 5: Reconnect the wiring harness.

3. Inspect and Replace Catalytic Converter

• Step 1: If the catalytic converter is damaged, remove it from the exhaust system.
• Step 2: Use a socket set to remove the bolts securing the catalytic converter.
• Step 3: Carefully remove the old catalytic converter and clean the mating surfaces on the exhaust system.
• Step 4: Install the new catalytic converter, ensuring proper alignment.
• Step 5: Secure it using new gaskets and bolts, torquing them to specifications (typically around 25-30 lb-ft).

4. Reset the OBD-II System

• Step 1: Reconnect the negative battery terminal.
• Step 2: Use an OBD-II scanner to clear the P0420 code from the system.
• Step 3: Start the vehicle and allow it to run until it reaches operating temperature.