To add another data point;
I have had that happen a few times in my 2015, same issue - no sound including turn signals. Have the latest software update AFAIK. It has occurred with and without my iphone attached, and usually happens mid-drive (working sound, then no sound). A couple times it has happened immediately after pressing the voice command button. In all cases, an ignition off and on cycle has cleared the problem. However, this is not always so easy to do, particularly if you are driving with a group in the car (embarrassing), on the freeway (dangerous), etc. This is a genuine problem that GM should rectify, however it is something that is impossible to replicate since it happens so infrequently.
There is a FMVSS requirement for turn signal flashers, but the audible part seems to be optional:
S9.2 Turn signal flasher.
S9.2.1 The means of producing the turn signal pilot indicator signal may be incorporated in the flasher. A means of producing an audible signal may be incorporated in the flasher.
That said, persons that experience this and have not received a satisfactory reply from the dealer can post a complaint on the NHTSA website for safety issues; I doubt NHTSA would take any action but it might get the attention of GM.
This is the web page for safety-related complaints:
https://www-odi.nhtsa.dot.gov/VehicleComplaint/
I have had that happen a few times in my 2015, same issue - no sound including turn signals. Have the latest software update AFAIK. It has occurred with and without my iphone attached, and usually happens mid-drive (working sound, then no sound). A couple times it has happened immediately after pressing the voice command button. In all cases, an ignition off and on cycle has cleared the problem. However, this is not always so easy to do, particularly if you are driving with a group in the car (embarrassing), on the freeway (dangerous), etc. This is a genuine problem that GM should rectify, however it is something that is impossible to replicate since it happens so infrequently.
There is a FMVSS requirement for turn signal flashers, but the audible part seems to be optional:
S9.2 Turn signal flasher.
S9.2.1 The means of producing the turn signal pilot indicator signal may be incorporated in the flasher. A means of producing an audible signal may be incorporated in the flasher.
That said, persons that experience this and have not received a satisfactory reply from the dealer can post a complaint on the NHTSA website for safety issues; I doubt NHTSA would take any action but it might get the attention of GM.
This is the web page for safety-related complaints:
https://www-odi.nhtsa.dot.gov/VehicleComplaint/
