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

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, multimeter, exhaust pressure gauge, safety glasses, gloves.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the battery to prevent any electrical issues.

2. Inspect and Replace Oxygen Sensors

• Sub-steps:
  1. Locate the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
  2. Use a socket wrench to carefully remove the oxygen sensors by turning counterclockwise.
  3. Inspect the sensors for damage or contamination.
  4. If faulty, replace with new OEM or high-quality aftermarket sensors.
  5. Reconnect the connectors securely.

3. Check and Replace Catalytic Converter (if necessary)

• Sub-steps:
  1. Inspect the catalytic converter for visible damage, dents, or excessive rust.
  2. If needed, remove the exhaust brackets and bolts securing the catalytic converter using a socket set.
  3. Carefully lower and remove the catalytic converter from the exhaust system.
  4. Install the new catalytic converter, ensuring proper alignment with the exhaust pipes.
  5. Torque all bolts to the manufacturer’s specifications, usually around 25-30 ft-lbs, but verify with service manual.

4. Clear Codes and Test

• Sub-steps:
  1. Reconnect the battery.
  2. Use the OBD-II scanner to clear the P0420 code from the vehicle's computer.
  3. Start the engine and allow it to reach operating temperature.
  4. Take the vehicle for a test drive to monitor performance and ensure the check engine light does not reappear.