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

Solution

1. Preparation

• Tools Required: OBD-II scanner, multimeter, socket set, torque wrench.
• Ensure the vehicle is on a flat surface and securely lifted if needed.

2. Replace Faulty Oxygen Sensors

• Sub-steps:
  1. Disconnect the battery to prevent electrical issues.
  2. Locate the upstream and downstream oxygen sensors (typically near the exhaust manifold and after the catalytic converter).
  3. Use a socket to remove the faulty oxygen sensors.
  4. Install new oxygen sensors and torque them to the manufacturer's specifications (usually around 30 Nm).
  5. Reconnect the battery.

3. Inspect and Replace Catalytic Converter (if necessary)

• Sub-steps:
  1. Remove the exhaust heat shield if applicable.
  2. Unbolt the catalytic converter from the exhaust system using a socket set.
  3. Inspect the old catalytic converter for signs of damage or blockage.
  4. Install the new catalytic converter, ensuring proper alignment and sealing.
  5. Tighten bolts to manufacturer's specifications (typically 40-50 Nm).
  6. Reinstall the exhaust heat shield.