We prove a functional central limit theorem for the position of a tagged particle in the one-dimensional asymmetric simple exclusion process for hyperbolic scaling, starting from a Bernoulli product measure conditioned to have a particle at the origin. We also prove that the position of the tagged particle at time
t depends on the initial configuration, through the number of empty sites in the interval
[0,(p−q)αt] divided by
α, on the hyperbolic time scale and on a longer time scale, namely
N4/3.