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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to prevent electrical short circuits.
• Ensure the vehicle is on a level surface and secure it with wheel chocks.

2. Inspect and Replace Oxygen Sensors

1. Remove the Undercover:
   • Use a socket set to remove any bolts securing the undercarriage cover.
2. Access the Oxygen Sensors:
   • Locate the upstream and downstream oxygen sensors on the exhaust system.
3. Disconnect the Sensors:
   • Carefully unplug the electrical connectors from both sensors.
4. Remove the Sensors:
   • Use an oxygen sensor socket to unscrew the sensors from the exhaust.
5. Install New Sensors:
   • Apply anti-seize compound to the threads of the new sensors.
   • Screw the new sensors into place and tighten to the manufacturer’s specifications (typically about 30 ft-lbs).
6. Reconnect the Sensors:
   • Plug in the electrical connectors to the new sensors.

3. Inspect and Replace Catalytic Converter (if necessary)

1. Inspect the Catalytic Converter:
   • Check for any physical damage or excessive carbon build-up.
2. Remove the Catalytic Converter:
   • Disconnect the exhaust pipes on both sides of the catalytic converter.
   • Remove any mounting bolts or clamps holding the converter in place.
3. Install the New Catalytic Converter:
   • Position the new catalytic converter and secure it with the appropriate bolts and clamps.
   • Reconnect the exhaust pipes ensuring a tight seal.
4. Recheck All Connections:
   • Ensure that all connections and sensors are securely in place.

4. Clear Codes and Test Drive

1. Reconnect the Battery:
   • Reattach the negative battery terminal.
2. Clear the Codes:
   • Use the OBD-II scanner to clear the P0420 code from the vehicle’s memory.
3. Test Drive:
   • Drive the vehicle under various conditions to ensure the code does not return and that performance is restored.