I have a Honda Accord 93 SE. Its ABS light comes on intermittently. When it is about to come on, there is some machanical sounds associate with it. After that, my brake pedal would vibrate and not go down when I stepped on it. The problem happens intermittently, and the Honda dealership nearby refuses to diagnose it. The technician at the dealership said that it he can only diagnose it if it happens all the time. Please help. Thank you.

You may have two unrelated things going on. Have your brakes looked at just to make sure the pads are fine and the rotors are not warped. If they are, you could get that vibrating sensation. The ABS system will disable itself if the speed sensors are not working properly which would turn on the ABS light to let you know its disabled.

when is the last time u did anything to the brakes? wheel speed sensor get dirty as the brake pad wearing out and cause the sensor to pick up false signal and cause the computer to activate the abs. check the wheel speed sensor and clean it if necessary. also check the tone ring on the axle shaft for cracks and missing teeth. if the ring is bad, it will also cause the sensor to pick up false signal.

Thank you very much for your info. I will recheck those items.