how to fix P0420 code in Tesla Model 3 Original (2017-2023)

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Park the vehicle on a level surface and engage the parking brake.
• Disconnect the negative battery terminal to ensure safety.

2. Inspect and Replace Faulty Oxygen Sensors

• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors in the exhaust system.
  2. Disconnect the electrical connectors from the faulty oxygen sensors.
  3. Use an O2 sensor socket to remove the sensors from the exhaust system.
  4. Install new oxygen sensors by screwing them into place and tightening to manufacturer specifications (typically 30-40 ft-lbs).
  5. Reconnect the electrical connectors.

3. Inspect and Replace the Catalytic Converter (if necessary)

• Sub-steps:
  1. Remove the exhaust manifold or exhaust pipes connected to the catalytic converter (if applicable).
  2. Unscrew and remove any mounting bolts or clamps securing the catalytic converter.
  3. Carefully remove the old catalytic converter from the vehicle.
  4. Install the new catalytic converter, ensuring proper alignment and securing it with bolts or clamps.
  5. Reconnect any exhaust components removed previously.

4. Reset the Engine Control Module (ECM)

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