ABS light on with triangle with ! in the middle. on 1999 BMW 323is

What do these lights indicate? Car runs great?

Asked by for the 1999 BMW 323is
Your anti-lock brake system has registered a fault and the system will need to be checked out to determine what is wrong. When the ABS light is on you will not have the anti-lock brake operation during hard braking, so if you have to stop quickly the wheels may lock up and you will not be able to keep control of the vehicle like you would if the ABS was working.