how to resolve P0420 error code on my Tesla Model 3 Highland (2024-present)

Solution

1. Preparation

• Gather tools: OBD-II scanner, infrared thermometer, basic hand tools (socket set, wrenches), multimeter, and safety goggles.
• Disconnect the vehicle battery to prevent electrical shorts or issues during the repair process.

2. Inspect and Replace Oxygen Sensors (if necessary)

1. Locate the upstream and downstream oxygen sensors on the exhaust system.
2. Using the appropriate socket, carefully remove the oxygen sensors from their respective locations.
3. Inspect the sensor connectors for corrosion or damage; clean or replace if needed.
4. Install new oxygen sensors, ensuring to torque them to the manufacturer’s specifications (typically around 30 ft-lbs).
5. Reconnect the connectors and ensure they are secured properly.

3. Evaluate and Replace Catalytic Converter (if necessary)

1. If the previous steps did not resolve the P0420 code, inspect the catalytic converter for physical damage or clogging.
2. For replacement, unbolt the catalytic converter from the exhaust manifold and the exhaust pipe using the socket set.
3. Remove any heat shields or brackets that may obstruct access to the catalytic converter.
4. Install the new catalytic converter, ensuring proper alignment with the exhaust components.
5. Torque all fasteners to the manufacturer’s specifications and reattach any heat shields.

4. Clear Error Codes

1. Reconnect the vehicle battery.
2. Use the OBD-II scanner to clear the P0420 error code from the vehicle’s computer.
3. Start the engine and let it idle for a few minutes to ensure everything is functioning properly.