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

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Ensure the vehicle is parked on a level surface and the parking brake is engaged.
• Disconnect the negative battery terminal to prevent electrical issues.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, torque wrench, penetrating oil.
• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors on the exhaust system.
  2. Apply penetrating oil to the sensor threads if they are rusted.
  3. Disconnect the electrical connectors from both sensors.
  4. Remove the sensors using the O2 sensor socket.
  5. Install new oxygen sensors, tightening them to the manufacturer’s specification (usually around 30-40 Nm).
  6. Reconnect the electrical connectors.

3. Inspect and Replace Catalytic Converter (if necessary)

• Tools Required: Socket set, torque wrench, exhaust hanger removal tool.
• Sub-steps:
  1. Inspect the catalytic converter for any signs of damage or clogging.
  2. If removal is necessary, disconnect the exhaust pipes at the flanges.
  3. Remove any exhaust hangers using the exhaust hanger removal tool.
  4. Replace the catalytic converter with a new unit, ensuring proper alignment with the exhaust system.
  5. Reattach the exhaust pipes to their respective flanges and tighten bolts to the manufacturer’s torque specifications (typically around 25-35 Nm).
  6. Reinstall the exhaust hangers securely.

4. Clear Codes and Test

• Tools Required: OBD-II scanner.
• Sub-steps:
  1. Reconnect the negative battery terminal.
  2. Use the OBD-II scanner to clear the P0420 code.
  3. Start the vehicle and allow it to reach operating temperature.
  4. Monitor the vehicle for any return of the check engine light.