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

Solution

1. Preparation

• Gather tools and parts required for repair.
• Disconnect the battery to ensure safety while working on electrical components.

2. Replace Faulty Oxygen Sensors (if needed)

• Tools Required: O2 sensor socket, torque wrench, safety gloves, and a ratchet.
• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors.
  2. Disconnect the electrical connectors from both sensors.
  3. Use the O2 sensor socket to remove the sensors from the exhaust system.
  4. Install new sensors by threading them in by hand, then tighten to the manufacturer's specifications using the torque wrench.
  5. Reconnect the electrical connectors securely.

3. Inspect and Replace Catalytic Converter (if needed)

• Tools Required: Socket set, torque wrench, jack and jack stands, safety goggles.
• Sub-steps:
  1. Raise the vehicle securely using a jack and place jack stands underneath.
  2. Disconnect the exhaust piping from the catalytic converter by removing the bolts or clamps.
  3. Remove any mounting hardware securing the catalytic converter to the vehicle.
  4. Install the new catalytic converter, ensuring it is aligned properly.
  5. Reattach the exhaust piping and secure with bolts or clamps, tightening to the manufacturer's specifications.

4. Clear Error Codes

• Tools Required: OBD-II scanner.
• Sub-steps:
  1. Reconnect the vehicle battery.
  2. Use the OBD-II scanner to clear the P0420 code from the ECU.
  3. Perform a short test drive to ensure the code does not return.