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

Solution

1. Preparation

• Tools Required: OBD-II scanner, multimeter, socket set, torque wrench
• Safety Warnings: Disconnect the vehicle's battery before starting work on electrical components.

2. Inspect and Replace Oxygen Sensors

1. Locate the upstream and downstream oxygen sensors on the exhaust system.
2. Disconnect the electrical connectors from both sensors.
3. Use a socket wrench to remove the sensors from their mounting positions.
4. Install new oxygen sensors by reversing the removal process. Ensure they are tightened to the manufacturer's specified torque (usually around 30 Nm).
5. Reconnect the electrical connectors securely.

3. Inspect and Replace Catalytic Converter

1. If the oxygen sensors are functioning correctly, assess the catalytic converter.
2. Remove any necessary heat shields and exhaust clamps to access the catalytic converter.
3. Use a socket set to unbolt the catalytic converter from the exhaust manifold and the exhaust pipe.
4. Inspect the old catalytic converter for signs of damage, such as physical blockages or severe discoloration.
5. Install the new catalytic converter, ensuring that all gaskets are in place and the bolts are tightened to the specified torque (usually around 40 Nm).
6. Reinstall any heat shields and clamps that were removed.

4. Clear Codes and Test

1. Reconnect the battery and use an OBD-II scanner to clear the P0420 code from the vehicle's computer.
2. Start the engine and allow it to reach operating temperature.
3. Conduct a test drive to monitor performance and check for the reoccurrence of the check engine light.