96 Jetta P0715 code

Can someone please help? I have a 96 jetta 2.0 with A/trans. I am getting a P0715 code which is InputTurbine/Speed Sensor Circ. Malfunction. The problem is that it isn't shifting correctly and the shift indicator light changes while in the same gear. I changed the neutral switch (multi funtion switch)and the trans. filter and fluid, checked the wiring and can't figure it out. Help please???