2011 brake issue.

[Gbuhl1]

Recently bought a 2011 Sequoia. Previous owner had the brake fluid flushed and then had a problem with a soft peddle. Dealership bleed it several times and eventually put in a new master cylinder before we bought it. Problem still exists. Peddle almost hits the floor. My mechanic has manually bled the brakes several times, put in another master cylinder and brake booster (there was a code) and bled brakes with scan tool. Nothing so far has worked. Next step is abs system unless someone here has an idea. Thx