If you are upgrading from a 4" Display to 8" OR upgrading from a 4" to 12" Sync 4 Touchscreen Display Ford Sync 3 or Sync 4 system, an OBD Genie F-428 is required to make a change to the vehicle's factory installed ACM (audio control module).
If when you make a phone call from SYNC, the remote party can hear you, but you cannot hear them through the vehicle's speakers & when you press the voice button on the steering wheel, you do not hear the voice prompts from the SYNC system.
Typically, either the didn't use the F-428 Genie programmer or it didn't work.