I have a 2013 model 4 with the solar sunroof pkg, which included the upgraded audio, center console display. Just recently the Voice CALL command stopped working. My phone was recently re-paired with the car's Bluetooth and does work. After pressing the voice button on the steering wheel, I am prompted for a command. I say CALL "<first name> <last name>" and the response is "Pardon". On the voice command screen on the center console display, only the CALL command is greyed out. The DIAL command as well as the other common commands are highlighted. Any help would be appreciated. Thanks. Update: I figured it out! FYI: The problem was that I recently re-paired my phone via the car's Bluetooth, but didn't download my personal contacts. To do this, essentially you press (may not be accurate) SETUP->PHONE->CONTACTS->UPDATE. Now quickly go to your phone and hit OK to allow contact transfer. That's it! Now via voice command, "CALL <first name, last name>" works. The CALL command is highlighted like the other common commands.
Baystater, I have a similar problem. 2012 Prius 4, with the same package and iPhone 4 (non siri). Contacts are loaded (I thought this happened automatically when pairing) but when I answer the prompt, nothing happens. This feature worked fine since the car was new. I will try re-synching as you suggest. Hope this does it.