how to fix Tesla Model 3 Original (2017-2023) check engine light for P0420 code?

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the vehicle's battery to ensure safety while working on the electrical system.

2. Inspect and Replace Oxygen Sensors

• Remove the oxygen sensor located before the catalytic converter and inspect for damage or contamination.
  • Tools Required: O2 sensor socket, ratchet.
  • Safety Warning: Allow the exhaust system to cool before touching components.
• If faulty, replace with a new sensor, ensuring to torque to manufacturer specifications.
• Repeat the inspection and replacement for the downstream oxygen sensor.

3. Inspect and Replace Catalytic Converter

• If the oxygen sensors are functioning properly, inspect the catalytic converter.
• If damaged or clogged:
  • Remove the exhaust piping connected to the catalytic converter.
    • Tools Required: Socket set, exhaust pipe cutter (if necessary).
  • Remove the catalytic converter from its mounting.
  • Install the new catalytic converter, ensuring all gaskets are replaced and bolted securely.
  • Torque all bolts to manufacturer specifications.

4. Clear Codes and Test

• Reconnect the battery and use the OBD-II scanner to clear the P0420 code.
• Start the vehicle and allow it to reach normal operating temperature.
• Monitor the vehicle’s performance and check for the reappearance of the check engine light.