I'm not being snarky, but it's painful to watch people flailing around trying to describe what is needed to set set auto-open distance. When in doubt read the manual:
Resetting the Location of the HomeLink Device
If you experience situations in which you sometimes drive up to your HomeLink Device and it doesn't open, or the HomeLink icon on the touchscreen's status bar does not display the dropdown when you approach the device, you may need to reset the device's location. To do so, park as close as possible to the HomeLink device (garage door, gate, etc.) and display the HomeLink settings page by touching Controls > Settings > HomeLink. Choose the name of the programmed device, and touch Reset Location.