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 
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Advisor can run a check.
See also:
Window Lockout
This feature prevents the rear passenger windows from operating, except from
the driver position.
Press to activate the rear
window locks. An indicator light will illuminate when the featu ...
Checking Engine Oil
It is a good idea to check the engine oil level at each fuel fill. In order
to get an accurate reading, the vehicle must be on level ground.
The engine oil dipstick handle is a yellow loop. See En ...
Calling for Service
When calling Roadside Service,
have the following information
ready:
- Your name, home address, and
home telephone number.
- Telephone number of your
location.
- Location of the vehicle.
- ...