Driving on Grades
Reduce speed and shift to a lower gear before starting down a long or steep downgrade. If the transmission is not shifted down, the brakes might have to be used so much that they would get hot and no longer work well. See “Automatic Engine Grade Braking” within Tow/Haul Mode on page 9‑26.
The vehicle can tow in D (Drive).
Use a lower gear if the transmission shifts too often.
When towing at high altitude on steep uphill grades, engine coolant will boil at a lower temperature than at normal altitudes. If the engine is turned off immediately after towing at high altitude on steep uphill grades, the vehicle may show signs similar to engine overheating.
To avoid this, let the engine run while parked, preferably on level ground, with the transmission in P (Park) for a few minutes before turning the engine off. If the overheat warning comes on, see Engine Overheating on page 10‑18.
On a long uphill grade, shift down and reduce the vehicle speed to around 88 km/h (55 mph) to reduce the possibility of the engine and the transmission overheating.
See also:
Vehicle Personalization
The audio system controls are used to access the personalization menus for customizing
vehicle features.
CONFIG (Configuration): Press to access the Configuration Settings Menu.
MENU/SELECT Knob: ...
Automatic Transmission Shift Lock Control Function Check
WARNING
When you are doing this inspection, the vehicle could move suddenly. If the vehicle
moves, you or others could be injured.
1. Before starting this check, be sure there is enough room aroun ...
Unable to Connect to OnStar Message
If there is limited cellular coverage or the cellular network has reached maximum
capacity, this message may come on. Push Q to try the call again or try again after
driving a few miles into anoth ...