how to fix a P0420 code on my Tesla Model 3 Original (2017-2023)

Solution

1. Preparation

• Gather necessary tools and parts.
• Park the vehicle on a flat surface and engage the parking brake.
• Disconnect the negative battery terminal to prevent electrical shock.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, torque wrench, multimeter.
• Sub-steps:
  1. Locate the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
  2. Disconnect the electrical connectors from both sensors.
  3. Use the O2 sensor socket to remove the upstream sensor first.
  4. Install the new upstream sensor, tightening it to the manufacturer's specified torque (typically around 30 lb-ft).
  5. Repeat the process for the downstream sensor.
  6. Reconnect the electrical connectors for both sensors.

3. Inspect and Repair Exhaust System

• Tools Required: Socket set, jack and jack stands.
• Sub-steps:
  1. Raise the vehicle using a jack and secure it with jack stands.
  2. Visually inspect the entire exhaust system for cracks, holes, or loose connections, focusing on the area around the catalytic converter.
  3. If any leaks or damages are found, replace or repair the affected sections of the exhaust system using appropriate exhaust repair products or components.

4. Replace Catalytic Converter (if necessary)

• Tools Required: Socket set, torque wrench, exhaust gasket.
• Sub-steps:
  1. If the catalytic converter is confirmed to be faulty, remove it by unbolting it from the exhaust system.
  2. Install the new catalytic converter, ensuring a proper fit and sealing with a new exhaust gasket.
  3. Tighten all bolts to the manufacturer's specified torque.

5. Reset the Engine Control Module (ECM)

• Reconnect the negative battery terminal.
• Start the vehicle and allow it to reach operating temperature.
• Use the OBD-II scanner to clear the P0420 code from the ECM.