Hey I have a 2005 Toyota Prius and I just started having some problems. I have the feature where when you put your hand up to the door handle it detects the FOB in your pocket and unlocks the car, when you want to lock the car you can also do so by pushing the black square on the door handle. Well this feature just stopped working, I can't unlock or lock the car using the hand detection on the door handle, it just makes a loud beeping noise instead and I am forced to use the FOB to lock my car.
You have a bad battery in your fob also I noticed if you have your fob in your pocket with your smart phone it messes up the signal. Just remembered there is a switch under the stearing wheel make sure it is on.
