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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to prevent any electrical shorts.
• Ensure the vehicle is on a flat surface and use wheel chocks.

2. Inspect and Replace Oxygen Sensors (if faulty)

• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors on the exhaust system.
  2. Unplug the electrical connectors from the faulty sensors.
  3. Use an oxygen sensor socket to remove the faulty sensors.
  4. Install new oxygen sensors by reversing the removal steps, ensuring proper torque specifications (typically around 30 lb-ft).
  5. Reconnect the electrical connectors.

3. Inspect and Replace Catalytic Converter (if necessary)

• Sub-steps:
  1. Remove any heat shields or brackets securing the catalytic converter.
  2. Disconnect the exhaust pipes from the catalytic converter using a socket set.
  3. Remove the catalytic converter from the vehicle.
  4. Install the new catalytic converter, ensuring proper alignment.
  5. Reattach the exhaust pipes and secure with the appropriate torque (usually 30-40 lb-ft).
  6. Reinstall heat shields or brackets as needed.

4. Reconnect Battery and Clear Codes

• Sub-steps:
  1. Reconnect the battery terminals securely.
  2. Use the OBD-II scanner to clear the P0420 code from the ECU.
  3. Start the vehicle and let it idle for a few minutes.