Siri Eyes-Free allows drivers to activate Siri with a long press of the voice recognition button on the steering wheel, similar to way Siri is activated on an iPhone.
Previously, iPhone users needed to connect their smartphones via a USB cable to their Ford vehicles to use iPhone functions such as messaging or iTunes.
All SYNC-enabled vehicles -- model years 2011 and newer -- can take advantage of the software upgrade by downloading it to a USB drive to update the in-vehicle entertainment and communications system.
The software upgrade takes about 25 minutes to complete. During that time, the vehicle can be driven, but the infotainment system will be offline.
SYNC is installed in more than 12 million vehicles today and was the first to use the system to offer voice-activated technology to control smartphones.
With the new software upgrade, vehicles with SYNC can use Siri's voice-activated functions to:
"Siri Eyes-Free is another great voice-activated feature that not only adds convenience but helps our customers keep their eyes on the road and hands on the wheel," Sherif Marakby, director of Ford's electronics and electrical systems engineering, said in a statement.