GMC YUKON XL 2003 Manual page 215

SERVICE BRAKE BOOSTE
If your vehicle has vaccum assist power brakes, this
message will be displayed on the DIC when there is a
problem with the Supplemental Brake Assist system.
If the message is displayed immediately after starting
the vehicle or the message appears while driving,
your Supplemental Brake Assist system needs service.
See Brake System Warning Light on page 3-4 1.
1
Your brake system may
I
t
be working
properly if the SERVICE BRAKE BOOSTER
message is displayed.
If the brake system warning light is also on,
you should have the vehicle towed for service.
See "Brake System Warning Light" in the Index.
If the brake system warning light isn't on, you
still have brakes, but the supplemental brake
assist system may not operate properly. In
theevent of a vacuum loss, you may not have
vacuum power assist for braking. The brake
CAUTION: (Continued)
pedal will be harder to push ana
11 WIII
IaKe
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.
SERVICE 4 WHEEL STEER
If a problem occurs with the 4 wheel steer system, this
message will appear
on
the
DIC.
If this message
appears, stop as soon as possible, and turn off the
vehicle. Restart the vehicle and check for the message
on the DIC display. If the message is still displayed,
or appears again when you begin driving, the four wheel
steer system needs service.
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