A connector position assurance (CPA) device for assuring and for informing a user of the engagement of a female connector assembly and a male connector assembly in a connector apparatus, and the connector apparatus having the female connector assembly and the male connector assembly engaged together, when in full-lock position, by the CPA. The female and male connector assemblies having a female terminal position assurance (TPA) device and a male terminal position assurance (TPA) device. During transport, the female TPA is engaged, in a pre-set position or a pre-lock position, to the female connector assembly, while the male TPA is engaged, in a pre-set position or a pre-lock position, to the male connector assembly. Also during transport, a connector position assurance (CPA) device is, at a pre-set position or a pre-lock position, with the female connector assembly (FIG. 13A). At least a set of terminals is provided into each of the male connector assembly and the female connector assembly when each of their respective male TPA and female TPA is at a pre-set position or a pre-lock position. The set of terminals provided for the male connector assembly is secured thereto when the male TPA thereof is placed at a full-lock position. Similarly, the set of terminals provided for the female connector assembly is secured thereto when the female TPA thereof is placed at a full-lock position. Thereafter, the male connector assembly and female connector assembly are engaged together, and the engagement thereof is assured when the CPA device is pushed downward and placed at a full-lock position (FIG. 13B) and when a leg of the CPA blocks the inward movement of a flexible member of the female connector assembly.