What causes a transmission to stop shifting from 2nd gear when the speedometer stops working 2000 Camry?

If the spedometer is not working and the traansmision will not shift out of second it means the speed sensor is bad, unpluged or the wiring for it is damaged.

The shif6ts are controled by the ECM (computer) and if does not know the speed of the car, it will not shift.