how to fix Tesla Model 3 Highland (2024-present) check engine light code P0420

Solution

1. Preparation

• Gather tools and parts. Ensure the vehicle is parked on a flat surface and the engine is cool.
• Tools Required: OBD-II scanner, socket set, jack and jack stands, wrench set, multimeter, pyrometer.
• Safety Warnings: Disconnect the battery before working on electrical systems.

2. Inspect and Replace Oxygen Sensors

1. Locate the upstream and downstream oxygen sensors.
2. Disconnect the wiring harness from both sensors.
3. Use the appropriate socket to remove the sensors from the exhaust system.
4. Install new oxygen sensors, ensuring they are tightened to the manufacturer’s specifications (typically around 30 lb-ft).
5. Reconnect the wiring harness to both sensors.

3. Inspect and Replace the Catalytic Converter

1. Raise the vehicle using a jack and secure it with jack stands.
2. Locate the catalytic converter; it is usually between the exhaust manifold and the muffler.
3. Remove the exhaust pipes connected to the catalytic converter using the socket set, ensuring to remove any clamps.
4. Inspect the catalytic converter for signs of damage or clogging.
5. If necessary, replace the catalytic converter with a new unit, ensuring all gaskets and seals are replaced to prevent leaks.
6. Reattach the exhaust pipes, ensuring they are securely fastened.

4. Clear Codes and Test

1. Reconnect the battery.
2. Use the OBD-II scanner to clear the P0420 code.
3. Start the engine and allow it to reach operating temperature.
4. Perform a test drive to ensure the check engine light does not reappear.