my Tesla Model 3 Original (2017-2023) is showing error code P0420, what does that mean?

Solution

1. Preparation

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

2. Inspect and Replace Oxygen Sensors

• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors in the exhaust system.
  2. Carefully disconnect the electrical connectors from the oxygen sensors.
  3. Use an O2 sensor socket to unscrew and remove the faulty oxygen sensors.
  4. Install new oxygen sensors, ensuring they are torqued to the manufacturer’s specifications (usually around 30 lb-ft).
  5. Reconnect the electrical connectors securely.

3. Replace Catalytic Converter (if necessary)

• Sub-steps:
  1. Remove any bolts or clamps securing the exhaust system to the catalytic converter using a socket set.
  2. Carefully detach the catalytic converter from the exhaust system.
  3. Install the new catalytic converter, ensuring a proper fit with the exhaust system.
  4. Torque all bolts to the manufacturer’s specifications to avoid leaks (usually around 30 lb-ft).
  5. Reconnect any sensors or components that were removed during the process.

4. Reset Check Engine Light

• Sub-steps:
  1. Reconnect the negative battery terminal.
  2. Use the OBD-II scanner to clear the error codes from the vehicle's computer.
  3. Start the vehicle and allow it to reach operating temperature.