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

Solution

1. Preparation

• Tools Required: OBD-II scanner, multimeter, infrared thermometer, socket set, torque wrench, safety goggles, gloves.
• Ensure the vehicle is parked on a flat surface and the engine is cool.
• Disconnect the high-voltage battery before starting work to ensure safety.

2. Inspect the Exhaust System

• Sub-steps:
  • Visually inspect the entire exhaust system for signs of leaks or damage.
  • Check all exhaust clamps and connections for tightness.
  • Repair or replace any damaged sections of the exhaust system.

3. Test Oxygen Sensors

• Sub-steps:
  • Locate the upstream (pre-catalytic converter) and downstream (post-catalytic converter) oxygen sensors.
  • Using a multimeter, measure the voltage output of each sensor while the engine is running.
  • If the upstream sensor is not fluctuating between 0.1V and 0.9V, it may need replacement. The downstream sensor should have a stable voltage reading.

4. Replace Catalytic Converter (if necessary)

• Sub-steps:
  • If the catalytic converter is confirmed faulty, remove the heat shield (if applicable) and unbolt the catalytic converter from the exhaust system using a socket set.
  • Install the new catalytic converter in the reverse order, ensuring all connections are secure and torqued to manufacturer specifications.
  • Reattach the heat shield if applicable.

5. Reconnect Battery and Clear Codes

• Sub-steps:
  • Reconnect the high-voltage battery.
  • Use the OBD-II scanner to clear the P0420 code from the system.
  • Start the vehicle and allow it to reach normal operating temperature.