GMC 2003 Sierra - Manual (Page 219)

REDUCED BRAKE POWER
If yûur vehrtile has vacuum assist power brakes, this
msssags wfk bs drsplay&cJ and you may notion that Ih?
tiraine pedal is haïder to push and II will take longer
to stop. You may aJso hear a motor running end ieel a
slight \fibral)on in the brake pedal or steering lA/heej
when you apply or release ihe brake pedal even If your
foot is not on the brake pedaJ. Thjs indicates that the
Suppiarrental Brake Assist system is working to
mainlain braking power. If you are braking fightfy, you
may not notice any difterence in the operation of
your brakes.
This message may also be displayed for bnef periods if
you are driving at higher olevations and aro pumping
your brakes or braking hard. The message may
clear after you’ve lifted your loot from (he accoferaior
pedal an allowed the vehide to coast in gear or after you
have driver^ down to e lower elevation This Is a
nomnaf operation of your brake system and does not
require Ihat the brake system be serviced. However, If
the message does not clear, your brake system
needs service. Whilg the message is displayed yoo will
notice fhal the brake padaf is harder io push and it
will lake longer (o stop. See
Bratie System Warning
Light on page 3-40.
Your brake system may not be working
properly if the REDUCED BRAKE POWER
message is displayed. If this message comes
on and stays on while driving, pull off the road
and stop carefully. The brake pedal will be
harder to push and it will take longer to stop.
If the message is no longer displayed sHer you
have pulled off the road and stopped, you can
continue driving.
However, If the message is still displayed, or if
It comes on again when you are driving, there
is a problem with your brake system. If you
continue to drive with this message displayed
It can lead to an accident. You should have the
vehicle towed for service. Also, see Brake
System Wanning Light in the Index.
3-S4