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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to ensure safety while working on electrical components.
• Allow the vehicle to cool if it has been running recently.

2. Inspect and Replace Oxygen Sensors

• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors in the exhaust system.
  2. Unplug the electrical connectors from both sensors.
  3. Use a socket wrench to remove the sensors from their respective locations.
  4. Install new oxygen sensors, ensuring they are tightened to the manufacturer’s specified torque (typically around 30 Nm or 22 lb-ft).
  5. Reconnect the electrical connectors.

3. Inspect and Replace Catalytic Converter

• Sub-steps:
  1. Remove any exhaust hangers connected to the catalytic converter using a socket set.
  2. Disconnect the exhaust pipes from the catalytic converter.
  3. Remove the catalytic converter from the vehicle.
  4. Install the new catalytic converter, ensuring proper alignment.
  5. Reconnect exhaust pipes and hangers, torquing bolts to manufacturer specifications.

4. Reset the Engine Control Module (ECM)

• Sub-steps:
  1. Reconnect the vehicle battery.
  2. Use the OBD-II scanner to clear the P0420 code from the ECM.
  3. Start the engine and allow it to reach operating temperature.