The auto brake (and warning system), follow distance indication uses the window camera and the ultrasonic sensors are used for parking. If either is covered you will get a dash warning message with the affected system disabled. For example, ice will often cover one or more of the parking sensors which disables the system. The windshield camera can also be blocked by ice/snow. But the wipers reach it and will clear it off which eventually clears the ice. Pro-tip, make sure to clear the area just above the rearview mirror mount if there is anything on the windshield.