found this on the web (actual under the sister vehicle buick engore gx).
The Service All-Wheel Drive System and or All-Wheel Drive Off
messages may be displayed in the (DIC), Driver Information Center.
Upon a DTC scan check, it might be noted that DTC, C15C9 SYM02 is
set in history and upon the next full ignition cycle the AWD (AllWheel Drive) function will be restored.
If the messages are being displayed, the AWD (All-Wheel Drive)
system will be disabled without an actual fault.
It was found that there was a software issue with the K47 Rear
Differential Clutch Control Module.