During Anti-lock Brake system operation, brake pressures are modulated by cycling electric solenoid valves. The cycling of these valves can be heard as a series of popping or ticking noises. In addition, the cycling may be felt as a pulsation in the brake pedal. If Anti-lock operation occurs during a hard application of the brakes, some pulsation may be felt in the vehicle body due to fore and aft movement of vehicle suspension components.
Although ABS operation is available at virtually all vehicle speeds, it is automatically turn off at speeds below 7 mph. For this reason, wheel lockup may be perceived at the very end of an anti lock stop and is considered normal.