What was the code that could have affected the outcome of "The Reichenbach Fall"?

The code was not the mysterious key to any computer system in the world.

Moriarty reveals that he used 'traditional' methods of arranging the 3 break-ins, and it was merely the shock value of timing them to occur at the same time, and the fact that he was willing to be caught in the process makes people think that he has something bigger up his sleeve.

He wants to make the authorities and Sherlock to believe that this was a planned advertisement of Moriarty's computer key to distract them from his real plan of destroying Sherlock's reputation. Moriarty has become obsessed with Sherlock and wants more than anything else to demonstrate to Sherlock his superior abilities by setting a puzzle that he cannot solve.

The code is the first part of the bait that keeps Sherlock in the game, this is slowly replaced by wanting to save his reputation, followed by wanting to save the lives of his friends without losing his own.

Could Sherlock have guessed the way to call off the hitmen? We have seen him break riddles set by Moriarty before, but he has always had more to go on. Here he needs to be 100% sure he can call them off, before he leaves the roof - clearly he decides that he needs some more time to work out what do do next and that faking his death is the easiest way out. Also in the past, Moriarty has set riddles half-hoping that Sherlock would break them. This time Moriarty intends to set Sherlock an impossible scenario in order to dominate him once and for all. Of course it would also break the original Arthur Conan-Doyle story if Holmes and Moriarty do not 'die'.

The key thing in my mind is not 'how did he fake his death' as he was clearly planning something by talking to Molly before these events - it is more, how did he anticipate Moriarty's death, or how did he intend faking his death with Moriarty there watching.