how to fix P0420 code in Tesla Model 3 Highland (2024-present)

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the battery to prevent electrical issues during repairs.

2. Inspect and Replace Oxygen Sensors (if faulty)

• Tools Required: O2 sensor socket, torque wrench, penetrating oil.
• Steps:
  1. Locate the upstream and downstream oxygen sensors in the exhaust system.
  2. Apply penetrating oil to the sensor threads to ease removal.
  3. Use the O2 sensor socket to unscrew the faulty sensor(s).
  4. Install the new oxygen sensor(s) by threading them in and torqueing them to the manufacturer's specification (usually around 30-40 Nm).
  5. Reconnect the electrical connectors to the sensors.

3. Inspect and Replace the Catalytic Converter (if necessary)

• Tools Required: Socket set, jack and jack stands, exhaust gasket.
• Steps:
  1. Raise the vehicle using a jack and secure it with jack stands.
  2. Locate the catalytic converter and inspect for any visible damage or blockage.
  3. If replacement is needed, disconnect the exhaust pipes from the catalytic converter by removing the bolts using a socket.
  4. Remove the old catalytic converter and replace it with a new one, ensuring any exhaust gaskets are replaced as well.
  5. Reattach the exhaust pipes and torque the bolts to the manufacturer’s specifications.

4. Reconnect Battery and Clear Codes

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