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

Solution

1. Preparation

• Gather your tools and parts.
• Ensure the vehicle is parked on a level surface, and the engine is cool.
• Disconnect the battery to prevent electrical shorts.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, wrench set, torque wrench.
• Check the wiring and connectors of both pre- and post-catalytic oxygen sensors.
• If damaged, disconnect the sensors and remove them using the O2 sensor socket.
• Install new oxygen sensors by reversing the removal process, ensuring proper torque (typically 30 lb-ft).

3. Inspect and Replace Catalytic Converter (if necessary)

• Tools Required: Socket set, exhaust hanger removal tool, torque wrench.
• Remove any exhaust clamps and hangers securing the catalytic converter.
• Disconnect the exhaust pipes from the catalytic converter and remove it from the vehicle.
• Install the new catalytic converter, ensuring proper alignment and securing it with new gaskets if necessary.
• Torque the bolts to the manufacturer’s specifications (typically around 25 lb-ft).

4. Reconnect Battery and Clear Codes

• Reconnect the battery terminals.
• Use the OBD-II scanner to clear the P0420 code from the vehicle's computer.