I had this same issue. Sync not recognizing my audio commands. ?Removed fuse #79 (below glove box). Checked fuse with multimeter, but it had so much carbon deposit on it
that I had no reading. Cleaned carbon patina on fuse off with sandpaper. Checked fuse ...it was good. Reinstalled....sync working properly again.
There was enough carbon on the fuse to make the connection intermittent or just not there anymore.?
After running the car for a week the Sync problem came back. Will try the fuse pull plus the reset.
Well, no simple fix in my case. After taking car in to dealer turns out there was a fleet vehicle tracking cable still under the dashboard. Got that removed. Also replaced the controller module behind the radio as it seemed likely the fleet vehicle connections had done some damage to the module. At the same time my main battery for starting was showing correct voltage but was not really holding a charge correctly. That was causing my door locks not to consistently function. Fun ?.
Everything is working really good now after those fixes. Road tested with 5k miles. ?