Gen 2 2007 prius. Several months ago my battery on my one and only fob was getting low, so I went and had it replaced. After it was replaced I was no longer able to do the keyless entry and keyless start. I am able to press the buttons on the Fob and unlock the car that way but to start the car I have to insert it in the key hole. Not sure how to reprogram the FOB to do keyless stuff when everything else works.
There's a sks button under the dash on the driver's side, where your knee would normally rest. Press that button and see if the functions return. Maybe someone accidentally pressed the button and turned off the sks