Do not pump the brakes. Just hold the brake pedal down firmly and let antilock work. A slight brake pedal pulsation might be felt or some noise noticed, but this is normal.
Antilock Brake System (ABS)
Braking in EmergenciesChevrolet Cobalt Owners Manual. Engine Coolant Temperature Warning Light
This light comes on briefly
while starting the vehicle.
If it does not, have the vehicle serviced by the
dealer/retailer. If the system is working normally
the indicator light goes off.
Notice: Driving with the engine coolant temperature
warning light on could cause the vehicle to
overheat. ...