When you compressed the brake caliper pistons in for the new pads, did you open the bleeder screws? If you didn't it's possible that dirty fluid got pushed back up into the master cylinder and the ABS unit.....which has been known to damage the unit on some occasions.
Try bleeding the brake system with fresh brake fluid....some ABS units have bleeder screws on them so you'll need to bleed them first.
Try bleeding the brake system with fresh brake fluid....some ABS units have bleeder screws on them so you'll need to bleed them first.