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

Solution

1. Preparation

• Gather all necessary tools and parts.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Repair Exhaust Leaks

• Tools Required: Socket set, exhaust leak detector
• Inspect the exhaust manifold, pipes, and connections for leaks.
• If leaks are found, repair or replace the damaged sections of the exhaust system.
• Reconnect all components securely.

3. Replace Oxygen Sensors (if faulty)

• Tools Required: O2 sensor socket, torque wrench
• Locate the upstream and downstream oxygen sensors on the exhaust system.
• Disconnect the electrical connectors and remove the sensors using an O2 sensor socket.
• Install the new sensors, ensuring they are torqued to manufacturer specifications (typically around 30-35 ft-lbs).
• Reconnect the electrical connectors.

4. Replace Catalytic Converter (if necessary)

• Tools Required: Jack stands, socket set, torque wrench
• Safely lift the vehicle and support it with jack stands.
• Unbolt the catalytic converter from the exhaust system using the socket set.
• Inspect the old catalytic converter for damage or clogging.
• Install the new catalytic converter, ensuring all bolts are torqued to manufacturer specifications.
• Reconnect any exhaust hangers or heat shields.

5. Final Checks

• Reconnect the negative battery terminal.
• Clear the P0420 code using the OBD-II scanner.
• Start the vehicle and allow it to reach operating temperature.