K Bus Communication
WARNING: This page is about a different car, the 2021 Ford F-150. However, it is still accessible from the selected car via links, so may be relevant.
There is a communication circuit (K Bus) between the roof opening panel motor and the shield motor that is only for communication between the motors and not for service diagnostics. If this circuit is opened or shorted the sunroof system will not operate. When the K Bus circuit is repaired, normal system function will return.