GMC T-Series 2007 Owner's Manual page 155

ABS can change the brake pressure faster than
any driver could. The computer is programmed
to make the most of available tire and road
conditions. This can help you steer around
the obstacle while braking hard.
As you brake, the computer keeps receiving
updates on wheel speed and controls braking
pressure accordingly.
Remember: ABS does not change the time you
need to get your foot up to the brake pedal
or always decrease stopping distance. If you get
too close to the vehicle in front of you, you will
not have time to apply the brakes if that vehicle
suddenly slows or stops. Always leave enough
room up ahead to stop, even though you
have ABS.
Using ABS
Do not pump the brakes. Just hold the brake
pedal down firmly and let antilock work for you.
You might feel the brakes pulsate, or you
might hear air exhausting if your vehicle has
air brakes, but this is normal.
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