See also:

Shifting Into Four-Wheel Drive High or AUTO (Automatic Four-Wheel Drive)
Turn the knob to the Four-Wheel Drive High or AUTO position. This can be done at any speed, except when shifting from Four-Wheel Drive Low. The indicator light will flash while shifting. It will remai ...

Using the “List” Command
1. Press and hold for two seconds. 2. Say “Directory.” 3. Say “Hands-Free Calling.” 4. Say “List.” ...

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 ...