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

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the vehicle battery to prevent any electrical issues during repair.

2. Inspect and Repair Exhaust Leaks

• Tools Required: Socket set, exhaust leak detector solution.
• Visually inspect the exhaust system for any visible holes or cracks.
• Use exhaust leak detector solution to confirm any leaks.
• If leaks are found, repair or replace the affected sections before further diagnostics.

3. Replace Faulty Oxygen Sensors (if necessary)

• Tools Required: Oxygen sensor socket, torque wrench.
• If the upstream or downstream oxygen sensors are faulty, remove the old sensors using the oxygen sensor socket.
• Install new sensors and torque them to the manufacturer's specifications (typically around 30 lb-ft).
• Reconnect the electrical connectors to the sensors.

4. Replace the Catalytic Converter (if needed)

• Tools Required: Wrench set, gasket scraper, new gaskets, exhaust hanger removal tool.
• Remove the exhaust hangers to free the catalytic converter from the exhaust system.
• Detach the catalytic converter from the exhaust pipes by removing the bolts or clamps.
• Clean the mating surfaces on the exhaust pipes and install the new catalytic converter with new gaskets.
• Reattach the exhaust hangers and ensure everything is secured properly.

5. Reconnect Battery and Clear Codes

• Reconnect the vehicle battery.
• Use an OBD-II scanner to clear the P0420 code from the memory.
• Perform a test drive to monitor for any reoccurrence of the code.