2004 Oldsmobile Alero Owner's Manual - Page 181

Anti-lock Brake System (ABS) Your vehicle may have anti-lock brakes. ABS is an advanced electronic braking system that will help prevent a braking skid. United States Canada If your vehicle has anti-lock brakes, this warning light on the instrument panel will come on briefly when you start your vehicle. When you start your engine, or when you begin to drive away, your anti-lock brake system will check itself. You may hear a momentary motor or clicking noise while this test is going on, and you may even notice that your brake pedal moves or pulses a little. This is normal. 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 wheels are slowing down. If one of the wheels is about to stop rolling, the computer will separately work the brakes at each front wheel and at both rear wheels. 4-7