OnStar

See also:

Tire Pressure for High-Speed Operation
WARNING Driving at high speeds, 160 km/h (100 mph) or higher, puts an additional strain on tires. Sustained high-speed driving causes excessive heat buildup and can cause sudden tire failure ...

If the System Needs Service
If the navigation system needs service and the steps listed here have been followed but there are still problems, see your dealer for assistance. ...

Towing the Vehicle
Notice: To avoid damage, the disabled vehicle should be towed with all four wheels off the ground. Care must be taken with vehicles that have low ground clearance and/or special equipment. ...