A traction battery assembly includes, among other things, an array sense lead header of a battery array, a plurality of sense leads extending from the array sense lead header to areas of the battery array, and a battery pack module having a module connector. The battery pack module is configured to move relative to the battery array from a disengaged position where the module connector the array sense lead header are disengaged to an engaged position where the module connector and the array sense lead header are engaged.