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:
Potential Issues
Some OnStar services are disabled after five days. OnStar cannot perform Remote
Door Unlock or Stolen Vehicle Assistance after the vehicle has been off continuously
for five days. After five days, ...
Automatic Headlamp System
When it is dark enough outside, the headlamps come on automatically.
Do not cover the light sensor on top of the instrument panel or the headlamps
will come on when they are not needed.
The syst ...
Exit Lighting
The interior lamps come on when the key is removed from the ignition.
They turn off automatically in 20 seconds. The lights do not come on if the dome override button is pressed in. ...