Checking Brake Fluid
You can check the brake fluid without taking off the cap.

Look at the brake fluid reservoir. The fluid level should be above MIN. If it is not, have your brake system checked to see if there is a leak.
After work is done on the brake hydraulic system, make sure the level is above the MIN, but not over the MAX mark.
See also:
Purposeful technology
Comprehensive connectivity is enabled by OnStar's remote vehicle access,
which makes keeping tabs on the vehicle a breeze from anywhere with a smart
phone. Highlights include:
Passive entry
Hea ...
Towing a Trailer
WARNING:
The driver can lose control when pulling a trailer if
the correct equipment is not used or the vehicle is
not driven properly. For example, if the trailer is
too heavy, the brakes may ...
Error Messages
If Disc Read Error displays and/or
the disc comes out, it could be for
one of the following reasons:
• The disc has an invalid or
unknown format.
• The disc is not from a correct
region. ...
