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 vehicle is equipped with the Tire Pressure Monitoring System. If a diagnostics check is needed between e-mails, push 
, and an Advisor can run a check.
See also:
Headlamp Aiming
The headlamp aiming system has been preset at the factory.
If the vehicle is damaged in an accident, the aim of the headlamps may be affected
and adjustment may be necessary.
It is recommended tha ...
Voice Recognition
The voice recognition system uses commands to control the system and dial phone
numbers.
Noise: The system may not recognize voice commands if there is too much background
noise.
When to Speak: ...
Recommended Transfer Case Settings
You can choose among four driving settings:
Indicator lights in the dial show which setting you are in. The indicator lights will come on briefly when you turn on the ignition and one will stay on. ...