ABS light keeps coming on? on 1996 Toyota Avalon

My 1996 Toyota Avalon's ABS light keeps coming on. It's off when I start the car, and even when I go in reverse, but as soon as I start accelerating forward it comes on. Sometimes when I brake, you can hear a buzz/vibrating sound coming somewhere around the brake pedal. The brake pedal will vibrate at the same time. The dealer said that the ABS system is deactivated when that light comes on and it costs $100 bucks just to see what's wrong. Any ideas what's wrong or if it needs to get fixed?

Asked by for the 1996 Toyota Avalon
It sounds like a wheel speed sensor may be failing on your 1996 Toyota Avalon. When the ABS light comes on fault code(s) are stored in the ABS control module. These stored codes can be retrieved with a scan tool and used to help diagnose the fault. I am afraid you may need to pay someone to diagnose this problem for you. Paying for a proper diagnoses will probably save you money in the long run.
My avalon was doing the same thing. No fault codes appeared when scanned. The tech suggested I keep driving it until something fails. Does this sound right? Anybody have suggestions