In this paper the totally asymmetric simple exclusion process (TASEP) with parallel update on an open lattice of size L is considered in the maximum-current region. A formal expression for the generating function for the weight of configurations with N particles is given. Further an interpretation in terms of (u, l, d)-colored weighted Motzkin paths is presented. Using previous results (Woelki and Schreckenberg 2009 J. Stat. Mech. P05014, Woelki 2010 Cellular Automata pp 637–45) the generating function is compared with the one for a possible second-class particle dynamics for the parallel TASEP. It is shown that both become physically equivalent in the thermodynamic limit.