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:
Customer Assistance for TextTelephone (TTY) Users
To assist customers who are deaf, hard of
hearing, or speech-impaired and who use Text
Telephones (TTYs), Buick has TTY equipment
available at its Customer Assistance Center. Any
TTY user can comm ...
When the Light Flashes First and Then Is On Steady
If the light flashes for about a minute and then stays on, there may be a problem
with the TPMS. If the problem is not corrected, the light will come on at every
ignition cycle. See Tire Pressure ...
Hydraulic Power Steering
If your vehicle has hydraulic power
steering, it may require
maintenance. See Power Steering
Fluid (2.4L L4 Engine) or Power Steering Fluid
(3.6L V6 Engine).
If power steering assist is lost ...
