- One of the key requirements in many multi-agent teams is that agents must coordinate on specific as-pects of their joint task. Unfortunately, this coordi-nation may fail due to intermittent failures in sen-sor readings, communication failures, etc. A key challenge in model-based diagnosis of such coordi-nation faults is to represent the model coordination between the agents in a way that allows efficient de-tection and diagnosis, based on observations of the agents involved. Previous mechanisms are useful only for small groups as they represent the coordi-nation with binary constraints. This paper presents a model-based diagnosis (MBD) approach to co-ordination failure in which non-binary constraints are allowed. This model presents two advantages: (1) it appears quite frequently when modeling real problems, (2) it addresses large groups by gathering multiple coordinations in one constraint. To solve the diagnosis problem, we propose a matrix-based approach to represent the basic building blocks of the MBD formalization. This representation is both generic and efficient for large-scale teams.