With the anti-lock brake system, the light(s) will come on when your engine is started and may stay on for several seconds. That is normal.
If the light stays on, turn the ignition to OFF. Or, if the light comes on when you are driving, stop as soon as possible and turn the ignition off. Then start the engine again to reset the system. If the light still stays on, or comes on again while you are driving, your vehicle needs service. If the regular brake system warning light is not on, you still have brakes, but you do not have anti-lock brakes. If the regular brake system warning light is also on, you do not have anti-lock brakes and there is a problem with your regular brakes. See Brake System Warning and Parking Brake Indicator Light .
The anti-lock brake system warning light should come on briefly when you turn the ignition key to ON. If the light does not come on then, have it fixed so it will be ready to warn you if there is a problem.