Camry :: ABS Light Comes On Intermittently - Brake Pedal Makes Grinding Sound When Applied

I have a 2007 Toyota Camry 4 cylinder and the ABS light comes on intermittently. Not only does the light come on, but sometimes when I apply the brakes, the brake pedal makes a grinding, vibrating sound that I can hear and feel under my foot, and feels as if the brake pedal is going to go all the way to the floorboard. If I quickly pump the brake, it stops that sound and the brake works fine.

I have taken the car to O'Rileys and Firestone and they put it on the analyzer. Two codes come up which indicate that the right front ABS was bad and/or an open circuit. I replaced the ABS sensor, but the problem described above persists. I took it back to Firestone and the same codes displayed. Firestone said it was an open circuit and that I should take it to the Toyota Dealer. I called the Dealer and they want $135 to analyze the car. They won't tell me what they will do in the analysis. I also took it to Just Brakes and they kept it for 3 days and could not or did not do much other than suggest I take it to the Dealership. I have read that the Dealership will probably say the ABS computer needs to be replaced ($1,000). I have also read that the 2007 Camry Hybrid ABS brake system has been recalled, although my Camry is NOT the hybrid.

There has had two fender benders on the left front side and the right front passenger tire hit a curb which bent the tire, but the tire has been balanced (not sure if the wheels were damaged in these minor accidents or if the wheels could be causing this?) Other thing that occurred right before the ABS light started coming on, and the brake issue, is that the air conditioner went toes up, and there were small metal fragments within the air condition housing unit. I replaced the whole A/C unit. I haven't been able to assess if one would have anything to do with the other, but it is interesting that the ABS and brake issue all started within a few days of the A/C unit being replaced.