how to fix P0420 code in 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 high-voltage battery for safety.
• Allow the vehicle to cool down before beginning work.

Tools Required:

• OBD-II scanner
• Socket set
• Torque wrench
• Multimeter
• Safety goggles
• Gloves

2. Inspect and Test Oxygen Sensors

• Sub-step 1: Locate the upstream and downstream oxygen sensors on the exhaust system.
• Sub-step 2: Using a multimeter, check the voltage output of the upstream sensor; it should fluctuate between 0.1V and 0.9V.
• Sub-step 3: Check the downstream sensor in the same manner; it should ideally be stable if the catalytic converter is functioning properly.
• Sub-step 4: Replace any faulty oxygen sensors.

3. Examine Catalytic Converter

• Sub-step 1: Inspect the catalytic converter for physical damage or signs of blockage.
• Sub-step 2: If damage is found, remove the catalytic converter from the exhaust system.
• Sub-step 3: Test the catalytic converter for back pressure using a pressure gauge; readings outside manufacturer specifications indicate a malfunction.
• Sub-step 4: Replace the catalytic converter if it is confirmed to be defective.

4. Reinstall Components

• Sub-step 1: Reinstall the catalytic converter and ensure all bolts are torqued to the manufacturer's specifications.
• Sub-step 2: Reconnect all oxygen sensors and ensure their connectors are secure.
• Sub-step 3: Reconnect the high-voltage battery and any other disconnected components.