Vehicle and Power Issues
OnStar services require a vehicle electrical system, wireless service, and GPS satellite technologies to be available and operating for features to function properly. These systems may not operate if the battery is discharged or disconnected.
See also:
Parking
If the vehicle has a manual transmission, before getting out of the vehicle, move the shift lever into R (Reverse) if parking on a downhill slope. On a level surface or an uphill slope, use 1 (First) ...
Battery
Refer to the replacement number on the original battery
label when a new battery is needed.
DANGER:
Battery posts, terminals, and related accessories
contain lead and lead compounds, chemicals
...
Jump Starting (On-board with eAssist Only)
If the vehicle fails to crank, it may
be jump started by using the eAssist
battery to charge the 12-volt battery.
Use the following procedure to
activate the on-board jump start
using the DIC ...