So I recently went through the fun of programming a new 7251V Viper 2-Way LE Responder
Remote Replacement for my Prius. I figured I would save anyone else out there the trouble that I had with the programming. I noticed all of the information on the internet was not enough to actually get it working on a Prius. So here is how I got it working on my 2009 Toyota Prius.
1st you need to enter the remote into progamming Hold the Function button until the remote gives a long beep and LED light comes on the remote a (it takes about 8 sec.) Then press and hold the remote start buttom until the remote beeps 3 times and LED lights up. Now your ready to program the remote, you have 60 seconds to do the steps in the next 2 paragraphs.
One of the door has to be open . Turn on Prius so it says "Ready" and the ignition is fully on (this is the important part that none of the other forums talks about, the car must be running). As soon as you turn the car on you have 5 seconds to do the next step which is to press and release the control center button (Control center is just the antenna that is mounted on you windshield, it should have a blue light and a button that you can press). After you have done that you have another 5 seconds to press and hold the button after roughly 5 seconds of holding the button down the blue light will start blinking and if you have the system hooked up to more than just remote start and doors you may hear a chirp or horn honk, but in my case neither apply so I had to watch for the blinking light because that was my only indication.
Then you need to press the lock button on the remote and you will hear a success tone from the remote and maybe a chirp from the Viper system. After you are done with that you can turn the car off and hit the function button twice to exit and save the programming\paring information.
Does that help? I know this info would have helped me big time when I was going through it so I hope I can help others.