During simultaneous impacts in linkages connected by joints, there can be several sequences of pair-wise impulse propagation and the choice of the most accurate sequence involves a combinatorial evaluation of all possible impulse sequences.In this paper, a simultaneous impact algorithm for planar frictionless constrained multibody systems is proposed that does not require an impulse propagation sequence to be determined.The formulation is developed by extending the generalized Newtonian restitution model for simultaneous impacts in unconstrained rigid bodies presented in [1] to planar linkages connected by frictionless joints.The algorithm is a computationally efficient alternative to the modeling of collisions in force-based continuous-time domains [2, 3], never results in an increase in kinetic energy (K.E.) [1] and predicts contact separation between bodies having zero pre-impact relative velocity of approach.Results using the proposed algorithm showing various collision scenarios in constrained linkages are included in the paper.Furthermore, the solutions are compared with linear complementarity (LCP) [4]-based approach and simulation results from ADAMS software. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.