GMC 2003 Sierra - Manual (Page 217)

SERVICE BRAKE SYSTEM
If mere is a profile m wiifi itie braKe sysi-em, this
message will be dispJayed on tbe D3C. If Ihis message
appears^ stop as soon as possible and lum gff Ihe
vehicle. Restart Ihe vehicie and check for the message
on the Die display. If the massaga is still displayed,
or appears again when you begin driving, the brake
syatejti needs service.
SERVICE BRAKE BOOSTER
If your vehicle has vaccom assist power brakes, this
message will be displayed on the OIC when lhore is a
problem with the Supplemeotal Brake Assist system,
fi the message Is displayed immadiately after starting
the vehicle or the message appears while driving,
your Supplemental Brake Assist system needs service,
See Brake irVanrtJhig Light oa page 3-40.
A CAUTION:
Vour brake sysiem may nol be working
properly it the SERVICE BRAKE BOOSTER
message
is displayed^
It the brake system warning light is also on, you
should have the vehicle towed for service. See
"Brake System Warning Light' in the Index.
li the brake system warning light isn't on, you
still have brakes, but the supplemental brake
assist system may not operate properly. In the
event of a vacuum loss^ you may not have
vacuum power assist for braking. The brake
pedsi will be harder to push and 11 will take
longer to stop. If you continue to drive with this
message displayed It can lead to a crash. Have
the brake system serviced as soon as possible.
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