ABS light is on

Hi everyone. I hope one of you can help me. I have a 92 montero sr and the ABS light just recently came on the instrument panel. And the ABS do not kick in when braking hard. I just hate having to take it to the shop because I know it will be very expensive to repair. I was wondering if there is anything I could do or check myseft to try to fix the problem before having it checked at a shop?

Any help is appreciated, Thanks