Global Positioning System (GPS)
○ Obstruction of the GPS can occur in a large city with tall buildings; in parking
garages; around airports; in tunnels, underpasses, or parking garages; or in an
area with very dense trees. If GPS signals are not available, the OnStar system
should still operate to call OnStar. However, OnStar could have difficulty identifying
the exact location.
○ In emergency situations, OnStar can use the last stored GPS location to send to
emergency responders.
○ A temporary loss of GPS can cause loss of the ability to send a Turn-by-Turn Navigation
route. The Advisor may give a verbal route or may ask for a call back after the
vehicle is driven into an open area.
See also:
Special Application Services
• Severe Commercial Use Vehicles Only: Lubricate chassis components every 5 000 km/3,000 mi.
• Have underbody flushing service performed once a year. ...
Customer Assistance Offices (U.S. and Canada)
GMC encourages customers to call the toll-free number for assistance.
However, if a customer wishes to write or e-mail GMC, the letter should be addressed to:
United States
GMC Customer Assistance ...
Infants and Young Children
Everyone in a vehicle needs protection! This includes infants and all other children. Neither the distance traveled nor the age and size of the traveler changes the need, for everyone, to use safety r ...





