there is a road in zip 91355 (city of santa clarita) called Newhall Ranch road. from the corner of Rye Canyon Road to the 5, the road was opened last year. Google maps still shows as incomplete. does the z3 have this road connected to the 5 freeway? See snapshot below.

Not sure about the Z3 but Teleatlas does have it.

My camera phone is crappy, hopefully this picture can answer your question. I don't think the Z3 maps have this road.