Driving on Grades
Notice: Do not tow on steep continuous grades exceeding 6 miles (9.6 km). Extended, higher than normal engine and transmission temperatures may result and damage the vehicle. Frequent stops are very important to allow the engine and transmission to cool.
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.
On a long uphill grade, shift down and reduce the vehicle’s speed to around 45 mph (70 km/h) to reduce the possibility of the engine and the transmission overheating. If the engine does overheat, see Engine Overheating.
See also:
Control of a Vehicle
The following three systems help to control the vehicle
while driving—brakes, steering, and accelerator. At
times, as when driving on snow or ice, it is easy to ask
more of those control syste ...
Diagnostics
OnStar Vehicle Diagnostics will perform a vehicle check every month. It will
check the engine, transmission, antilock brakes, and major vehicle systems. It also
checks the tire pressures, if the v ...
Battery Run-Down Protection
This feature shuts off the dome, courtesy, and
vanity lamps if they are left on for more than
20 minutes when the ignition is off. This will keep
the battery from running down.
If the battery ru ...
