What is usually wrong with my ABS system when the ABS light brake light are on and the brakes work with a hard pedal pressure?
In most cases, the brakes will function fine even if the ABS is
not working (you just won't have the ABS feature). If you have to
exert more pressure than normal on the brakes, you can be looking
at an issue with the brake booster or some other part not
necessarily associated with the ABS system. It sounds like the ABS
light might be a secondary symptom of a larger problem. I would
recommend taking the vehicle to a qualified shop asap.