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

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Disconnect the vehicle's battery to ensure safety during repairs.
• Ensure the vehicle is on a flat surface and use wheel chocks for added safety.

2. Inspect and Test Oxygen Sensors

• Tools Required: OBD-II scanner, multimeter.
• Remove the connectors from the upstream and downstream oxygen sensors.
• Use the multimeter to measure the voltage output:
  • A healthy upstream sensor should fluctuate between 0.1V and 0.9V.
  • The downstream sensor should stabilize around 0.5V.
• If either sensor is faulty, proceed to replace it.

3. Replace Faulty Oxygen Sensors

• Parts Required: New upstream and/or downstream oxygen sensors (if needed).
• Remove the old sensor using an oxygen sensor socket.
• Install the new sensor and torque to manufacturer specifications (consult service manual for torque values).
• Reconnect the sensor connectors.

4. Inspect/Replace Catalytic Converter (if necessary)

• Tools Required: Wrench set, socket set.
• If the catalytic converter is damaged or has failed the inspection:
  • Remove the exhaust manifold and the connecting pipes if needed.
  • Unbolt the catalytic converter from the exhaust system.
  • Install the new catalytic converter and torque the bolts to the specified values from the service manual.
  • Reconnect any exhaust components that were removed.

5. Clear Codes and Test Drive

• Reconnect the battery.
• Use the OBD-II scanner to clear the P0420 code.
• Start the vehicle and perform a test drive to ensure the check engine light does not reappear.