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:
Warning Lights, Gauges, and Indicators
Warning lights and gauges can signal that something is wrong before it becomes serious enough to cause an expensive repair or replacement. Paying attention to the warning lights and gauges could preve ...
Rear Window Defogger
REAR (Rear Defogger): Press to turn
the rear window defogger on or off. The rear window defogger turns off after about
10 minutes. It can also be turned off by turning the ignition to ACC/ACCESSO ...
Driver Information Center (DIC) (With DIC Buttons)
If your vehicle has DIC buttons, the information below explains the operation of this system.
The DIC displays information about your vehicle. It also displays warning messages if a system problem is ...