When a customer upgrades from a 4" Display to 8" 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.
If you run into this concern, we see issues where the F-428 Genie programmer was not used or it didn't work.