how to fix P0420 code in Tesla Model 3 Highland (2024-present)?

Solution

1. Preparation

• Gather tools and parts.
• Ensure the vehicle is parked on a flat surface and the engine is cool.
• Disconnect the negative battery terminal to prevent electrical issues.

2. Inspect and Replace Oxygen Sensors

1. Locate Oxygen Sensors: Identify the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
2. Disconnect Electrical Connectors: Carefully unplug the electrical connectors from both oxygen sensors.
3. Remove Sensors: Use an O2 sensor socket to unscrew and remove both sensors from the exhaust system.
4. Install New Sensors: Apply anti-seize compound to the threads of the new sensors, then install and torque them to the manufacturer's specifications (usually around 30 ft-lbs).
5. Reconnect Electrical Connectors: Plug the connectors back into the new sensors.

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

1. Remove Exhaust Components: If the catalytic converter is suspected to be faulty, disconnect the exhaust pipe and any brackets securing the catalytic converter using a socket set.
2. Remove Catalytic Converter: Carefully take the catalytic converter out, ensuring no damage to surrounding components.
3. Install New Catalytic Converter: Place the new catalytic converter in position, using new gaskets as needed, and secure it with bolts to the exhaust system.
4. Reattach Exhaust Components: Reconnect all parts of the exhaust system securely.

4. Reset the OBD-II System

1. Reconnect Battery: Reconnect the negative battery terminal.
2. Use OBD-II Scanner: Clear the error codes using an OBD-II scanner and reset the check engine light.