how to fix P0420 code in 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's negative battery terminal for safety.

2. Inspect and Test Oxygen Sensors

• Tools Required:
  • OBD-II scanner
  • Multimeter
• Check the voltage output of the upstream oxygen sensor. It should fluctuate between 0.1V to 0.9V.
• If the sensor is faulty, replace it with a new one.

3. Replace the Catalytic Converter

• Tools Required:
  • Socket set
  • Torque wrench
  • Gasket scraper
• Remove the bolts securing the catalytic converter to the exhaust system.
• Carefully detach the catalytic converter and remove any old gaskets.
• Install the new catalytic converter with a new gasket, ensuring proper alignment.
• Torque the bolts to the manufacturer's specifications.

4. Reconnect Battery and Clear Codes

• Reconnect the negative battery terminal.
• Use the OBD-II scanner to clear the P0420 code from the system.
• Start the vehicle and allow it to reach operating temperature.