Let \( K_{1,1,5} \) be the graph obtained from \( K_{2,5} \) by adding an edge connecting two vertices of degree 5. In this paper, we prove that 4-connected planar \( K_{1,1,5} \)-minor-free graphs contain no vertex of degree more than five. We also provide a complete characterization of 4-connected, 4-regular, planar \( K_{1,1,5} \)-minor-free graphs.