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:
New for 2011
The Sierra Hybrid gets GM's OnStar 9.0 telematics system that GM says
provides better voice recognition. GM also said they have worked to cut down on
the amount of wind noise occupants hear. ...
Turning the Rear Vision Camera System Off or On
To turn off the rear vision camera system, press and hold , located on the inside rearview mirror, until the left indicator light turns off.
The rear vision camera display is now disabled.
To turn t ...
Automatic Dimming Mirror
If the vehicle has the automatic dimming mirror, the driver outside mirror automatically adjusts for the glare of the headlamps from behind.
This feature is controlled by the on and off setting on th ...