Locating the 16-digit ERC (Emergency Rescue Code) for your Toyota's head unit might differ based on your car model. Here's a common method to find your ERC code:

1. Hold the Main Button: Press and keep holding the main button on your navigation system.
2. Toggle Parking Lights: Turn your parking lights on and off three or four times consecutively until a new display shows up on the head unit.
3. Interact with Active Buttons: Follow the on-screen instructions, pressing only the highlighted or active buttons. This sequence should reveal a screen showing the 16-digit ERC serial number.
4. Alternative Methods: If this procedure doesn't apply to your specific model, you might need to look up the steps for your particular vehicle or seek further assistance.