2008 without smart entry and start failing to unlock doors

all of a sudden, my 2008 prius, basic package without the smart entry system, stopped locking or opening the doors when i pressed the button.
at first i thought it must be a dead battery, so i replaced it with a new one and got the exact same behavior. i checked the old battery and it was still giving off 3 volts as was the new one when i checked that with a volt meter. when i press any of the buttons on the key, a small led light goes on and on the dashboard a picture of a key lights up briefly. the owner's manual does not show the key as a warning light.

everything seems to work using the manual key on the doors and the stub stuck in the ignition slot to start the car.

ideas are most welcome.
thanks

 

battery is fine. car runs great though with slightly lower mileage after the local toyota dealer tuned it up a few weeks ago.

the base package when i bought it uses the same key, but you have to actually insert it into the slot to start the engine.

 

39K miles, tune up was 2 hours to change the oil and check fluid levels.
i just put my volt meter to the jump point under the hood and got 12.5 volts.

 

locks work fine from the door controls
the tune up was whatever they do at 35K miles, but they seemed to charge me for primarily an oil change.