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

Solution

1. Preparation

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

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, torque wrench, penetrating oil.
• Check the condition of the upstream and downstream oxygen sensors. If faulty, remove them:
  1. Spray penetrating oil on the sensor threads to loosen.
  2. Use the O2 sensor socket to unscrew the sensor from the exhaust manifold (upstream) and catalytic converter (downstream).
  3. Install new oxygen sensors, ensuring they are torqued to the manufacturer specifications (typically around 30 ft-lbs).

3. Inspect and Replace Catalytic Converter (if necessary)

• Tools Required: Socket set, torque wrench, exhaust gasket, heat-resistant gloves.
• If the catalytic converter is determined to be faulty, replace it:
  1. Locate and remove any heat shields covering the catalytic converter.
  2. Use a socket set to unscrew the bolts securing the catalytic converter to the exhaust system.
  3. Remove the old catalytic converter and replace it with a new one, ensuring to install a new exhaust gasket.
  4. Torque the bolts to the manufacturer's specifications.

4. Reconnect Battery and Clear Codes

• Reconnect the battery terminals securely.
• Use the OBD-II scanner to clear the P0420 code from the system.