how to resolve P0420 code in Tesla Model 3 Highland (2024-present)?

Solution

1. Preparation

• Ensure the vehicle is parked on a flat surface and the engine is cooled down.
• Disconnect the negative terminal of the battery to prevent electrical shorts.

2. Inspect and Test Oxygen Sensors

• Tools Required: OBD-II scanner, multimeter
• Remove the connectors from the upstream and downstream oxygen sensors.
• Use a multimeter to measure the output voltage of the sensors.
  • Upstream sensor: should fluctuate between 0.1V and 0.9V.
  • Downstream sensor: should be relatively stable.
• If either sensor is faulty, replace it.

3. Inspect Catalytic Converter

• Tools Required: Socket set, torque wrench
• Remove any heat shields or protective covers to access the catalytic converter.
• Visually inspect for physical damage or signs of overheating (e.g., discoloration).
• If the catalytic converter is damaged or clogged, replace it with an OEM equivalent.
  • Torque specifications for the exhaust bolts should be followed as per the service manual.

4. Clear Codes and Test Drive

• Reconnect the battery terminal.
• Use the OBD-II scanner to clear the P0420 code.
• Start the vehicle and perform a test drive to ensure the code does not reappear.