My on-order Prius will come with the Smart Key System. I've never owned a car with so much as automatic locks, so I'm struggling to understand this new technology. For the fans, what's so wonderful about it? What is the care and feeding--how often do you have to change the battery? Is the battery a dealer only part? I've read elsewhere that cell phones might interfere with the operation of the Smart Key. Is that true, and if so, how far apart do they have to be kept?

Linda, My understanding of the technology involved here is that they are a passive device similar to the electronic security tags that you'll find on merchandise in the store. They are also like the pass keys used on some toll roads or the ones you wave in front of the gas pump at Mobil gas stations. No battery required. They just echo back to the sending device be it your car, gas pump, or security scanner at the store. Also have not heard of any problems with cell phone use and these devices.

We have a Camry Hybrid with the smart key system and love it. It's handy when I have my year-old daughter and all her gear with me--just pull on the door and go.

One annoyance: if you open the driver's side door, only that door unlocks. If you open the passenger's side door, all the doors unlock. I'd prefer having all the doors unlock when the driver's door is opened. I've heard that this is a setting that can be changed by the dealer, but I haven't checked it out myself.

I was reading on the Camry forums about the cell phone issue. One post said that having the key and cell in the same pocket interfered with the key fob, but that as soon as he took the cell out of his pocket, it was fine.

As for the battery, I don't remember exactly what the manual says, but I seem to recall a diagram for replacing the battery yourself.

Enjoy the Prius!

Changing the battery in the Smart Key system yourself is not recommended, according to the manual, because of potential for damaging parts of the system inside the key.

I keep my Treo 650 and my TCH's Smart Key in my purse and have experienced no problems with the Smart Key system as a result, though I do keep the keyfob and the phone in separate pockets in my purse. I just walk up to the car and pull the door handle and it beeps twice (not the vehicle horn, just a little beep-beep) and unlocks. It is very convenient when I have my 2 year old son with me, because I can just open the front passenger door, drop the diaper bag on the front passenger seat, open the rear door and put him in his car seat without fumbling around for car keys or having to press the door lock switch.

I do believe you can have the settings changed so that all of the doors unlock when you pull the driver's door handle, but around here I would not want it to do that. If I am alone I want just the driver's door to open. If I have passengers with me and I need all of the doors to unlock for some reason (it's raining and we're all running for the car...) I get the keyfob out and use the button to unlock all of the doors.

With the SmartKey System, you can either leave the key in your pocket/purse, or you can just let it lie on your seat or cup holder. However, Toyota also has a place in the dash right behind the steering wheel to place the SmartKey fob as well. If you insert your SmartKey fob into that opening, you can't remove your fob until the car is placed back in "Park".

Though the SmartKey Systems has many advantages, it also has disadvantages as well. If the car is started with the key fob inside/around the vehicle, the car can be driven away once the fob is removed from the immediate area of the car. When this happens, you'll notice an amber colored "broken key" indicator on your dash. I've accidentally done this a few times when driving a family member's 05 Prius. Another downside to this is if you drive off without the key and turn the car off, you will not be able to restart it (a major advantage if someone else drives off with your car.)

Another thing to note is that with the key removed from the car, if someone presses the "Start" button on the dash, the car will not power up either (found this out by accident as well.)

I am sure you will like having the system. The SmartKey System allows you to open the driver's door, front passenger's door, or the rear hatch without having to press the "unlock" button. However, to lock the doors, you have to press the "Lock" button on the key fob. My mother-in-law's Prius won't allow her to lock her doors by pressing the "Lock" button on the door. When she does, her driver's door always unlocks as it thinks the key is inside. Another issue you'll hjave to get used to is checking locked doors. If you lock your car and test any of the doors with the sensor to ensure the car is locked, the door will unlock on you.

Good luck.

The Smart Key for your Prius (assuming you are getting an '06 like I have) is a pretty neat feature. Basically, as you come within proximity to your vehicle, it "knows" you are there and will unlock the door as you touch the door handle. Chances are, when you open the drivers door, it will open only that door, but if you open the front passenger door, all of the doors will open. That is the "default" setting.

This setting can be changed by YOU, and it tells you how to do it in the manual (or at the very least, one of us can tell you.) It's not hard. You use the fob and a push button sequence right on it.

I have not had any issues locking my doors with the "lock button" on the door. Just make sure you aren't doing it by grabbing the handle, and the car won't confuse you with trying to unlock the door.

Additionally, the "Smart Key" is also the ignition "key" however, using it in a traditional manner (actually inserting into the dashboard) is optional. I leave the fob in my purse, jump in the car and hit the power button. No key insertion required.

As for the bettery in the fob, the battery is user-replaceable. And the instructions are definitely in the manual. I just read how to do it the other day... Takes a standard Computer CMOS battery (button cell) that you can find at your local drug store, or worst case scenario, your local Radio Shack for a few bucks.

Good luck with your new car!

So how do you check to see if the doors are locked?

You can always hit the lock button on the fob to double check. My husband says that he likes to lock the car by pressing the button on the hatchback as he is walking away from the car. He says it's harder for the car to get "confused" because there is no handle to grab.

So much for a "smart" key system, huh?

A few weeks ago, I managed to kill my 2005 Prius smart key. I went canoeing, and nevr thought about what I was carrying in my pockets. Sure enough, we tipped over in a fairly strong current, and I had to be concerned first and foremost with the welfare of my rather elderly canoeing partner. I was in water to my chest for about 15 minutes.

by the time we got out and on the riverbank, my wallet, daily planner etc. were soaked through. I still didn't think about the smart key until I got home and the car alarm went off spontaneously. Next day the key would not work at all. I took it apart, took the battery out, and dried all the surfaces I could see, but no dice. Replacement cost is about $250, which makes for a rather expensive canoeing trip.

At the risk of exposing my continuing ignorance about this handy little feature, how do you drive the car once you've killed the Smart Key? I know I can open the car door using the cleverly attached master key, but the master key won't start the car. So I can get in and call Roadside Assistance for a tow?

P.S. Just reached the 47 MPG threshold on my second tank.