Saturn 2009 ASTRA - Manual (Page 164)

If the engine stops, there will still be
some power brake assist but it will be
used when the brake is applied.
Once the power assist is used up, it
can take longer to stop and the brake
pedal will be harder to push.
Adding non-dealer/non-retailer
accessories can affect vehicle
performance. See Accessories and
Modifications on page 9-3.
Antilock Brake
System (ABS)
This vehicle has the Antilock Brake
System (ABS), an advanced
electronic braking system that helps
prevent a braking skid.
When the engine is started and
the vehicle begins to drive away,
ABS checks itself. A momentary
motor or clicking noise might
be heard while this test is going on,
and it might even be noticed that
the brake pedal moves a little. This
is normal.
If there is a problem with ABS, this
warning light stays on. See
Antilock Brake System (ABS)
Warning Light on page 4-17.
Let us say the road is wet and you
are driving safely. Suddenly, an
animal jumps out in front of you.
You slam on the brakes and continue
braking. Here is what happens
with ABS:
A computer senses that the wheels
are slowing down. If one of the
wheels is about to stop rolling, the
computer will separately work
the brakes at each wheel.
ABS can change the brake pressure
to each wheel, as required, faster
than any driver could. This can help
the driver steer around the
obstacle while braking hard.
As the brakes are applied, the
computer keeps receiving updates
on wheel speed and controls braking
pressure accordingly.
Remember: ABS does not change
the time needed to get a foot
up to the brake pedal or always
decrease stopping distance. If you
get too close to the vehicle in
front of you, there will not be enough
time to apply the brakes if that
vehicle suddenly slows or stops.
Always leave enough room up
ahead to stop, even with ABS.
Using ABS
Do not pump the brakes. Just hold
the brake pedal down firmly and
let antilock work. The antilock pump
or motor might be heard operating,
and the brake pedal might be
felt to pulsate, but this is normal.
8-18 Driving and Operating