brakes not working

Hey all.. I have searched and searched and haven't been able to see if anyone has the same issue as me. 1998 gxl 105 1fz aus delivered auto I have c1256 Replaced pump motor, accumulator and done a rebuild on the master cylinder Still beeping still next to no brakes still bringing up c1256...

I have a 2004 GX470 with just over 200,000 miles on it. I was driving today when the VSC/TRAC/ABS/BRAKE lights all came on and a loud continuous alarm went off. I was able to drive it for a while with no issues with the breaking. After a few minutes of driving the brakes went hard and stopped...