Psm abs warning lights on

[STEVEG]

Hi, last week driving home, brake pedal lost pressure, pedal went slowly down to floor, ABS and PSM warning lights on, garage said master cylinder u/s, they fitted new master cylinder, ABS and PSM lights still on, they read fault codes and said that they were getting incorrect brake pressure readings, they said needs a new brake pressure sensor,they fitted a new brake pressure sensor, still the fault is there, any other ideas anyone?