Discovered something about electronic key fob...

This is probably nothing new to most of you, and I guess this all makes sense. I remember the salesman telling me that you can take your mechanical key out of your electronic key, leave the electronic key in the Prime, and lock the doors manually with the mechanical key, thus causing the Prime (and presumably all Prius models) to ignore the electronic key. He said this was so you don't have to carry the big electronic key around (the example he gave was going to the beach).

Today I came across another situation in which this functionality comes into play: If you leave one of your electronic keys inside your Prius Prime (and presumably other Prius models, and likely other Toyota models), and use your other electronic key to lock your Prime, your Prime will not recognize the electronic key you left inside in terms of letting you unlock your Prime via its proximity to the Prime.

In other words, try this: First, so you don't get locked out, roll down your window. Next, take one of your electronic key fobs and place it on the armrest of the driver's door. Press the lock button on your other electronic key fob to lock your Prime and then put that key fob away (at least several feet from your Prime). Then come back and try to open the driver's door by putting your hand on the exterior door handle. Nothing will happen. Your Prime won't unlock, even though your other electronic key fob is sitting right there on the armrest inside the car. If you reach in through your open window and press the unlock button on that electronic key fob, your Prime will unlock and that electronic key will now function as normal.

Although it is generally very difficult to accidentally lock yourself out of your Prime, there is one situation in which this functionality could easily become a problem and cause you to lock your keys in your car. Some alarms have passive arming. If you have this feature enabled, when you walk away from your car, it locks itself 30 or 60 seconds later. So, if you leave your key in your Prime and walk away, you will get locked out of your car. I tested this and it does happen. When the alarm passively arms and locks the doors, the Prime treats that in the same way as if it was locked with another electronic key, and it automatically ignores the electronic key locked in the Prime.

I would have thought that the electronic key being in the Prime would mean that it either wouldn't lock or that, if it did lock, you'd be able to just walk up and place your hand on the door handle to unlock your Prime and get inside.

 

Well, what my salesman said is correct. If you read what I stated in my original post, I have tried this, and it does work. Yes, your electronic key fob would still be in your car. If a thief broke in and found it, he could steal your car. However, if it is hidden well enough, this is not likely.

As I said, locking the car with electronic key fob in the car (via another electronic key, the mechanical key or an alarm's passive arming) causes the Prius to ignore the electronic key fob left in the car. Wrapping it in aluminum foil will also make the Prius not "see" it (I've tried this, too). You can also turn an electronic key fob "off" by pressing a combination of buttons on it (it puts it on standby or something like that). Taking it apart would be overkill, though I suppose if you hid the fob's battery in a second place that could slow a thief down considerably.

What is the hostility toward doing something that works? I read the pages you quoted in the manual, and they do not apply in any way to say that you shouldn't do what my salesman described about locking the car with the manual key while leaving the electronic key fob inside. What do you think? I mean, do you think the salesman somehow stumbled on this strange possibility and is lying about it being a function by design? Do you think that the way it functions is all by happenstance?

 

Sorry, I wasn't clear. Let me try to explain this more clearly:

I was speaking in terms of what my expectation was as far as what would happen when my alarm tried to passively arm my car. Passive arming (for those who might not know) is when an alarm will lock your and arm itself without any action from you. In other words, you walk away from your car and the alarm arms and locks the car (after a preset time, usually within 30 to 60 seconds).

In experimenting with passive arming yesterday, I had thought it wouldn't be possible to lock my electronic key in my Prime. I thought that if I accidentally left my electronic key in my Prime and the alarm tried to passively arm, it would either (1) sound a warning and not arm (like when you accidentally leave your electronic key in the Prime and try to lock the prime by touching the sensor on the door handle with) or (2) it would successfully lock the Prius with the electronic key fob inside.

I was speaking in terms of this second result. I thought that if the alarm did successfully lock the Prime with the electronic key fob inside, all I'd have to do is walk up to the Prime and put my hand on my exterior handle and the Prime would unlock. However, that was not what happened. That's when I remembered what the salesman had said and realized that the manner in which the alarm's passive arming operated must mimic locking the Prime with the mechanical key (which has the same result as locking the Prime with another electronic key fob while their is still one inside).

Clearly, if it what salesman described about locking a key fob in the car with the mechanical key (I'll refer to this as the "mechanical key option") is a feature, and if the passive arming mimics that, then the passive arming would have to similarly temporarily deactivate whatever electronic key fob is left in the car (even though I left it in their by mistake). In other words, you are right. If the mechanical key option (using the mechanical key to purposefully lock the Prime with an electronic key fob left inside that is thereby temporarily deactivated) left you able to walk up to the Prime and unlock it by touching the exterior door handle, that would make no sense whatsoever.

So, I just hadn't thought about that mechanical key feature coming into play with an alarm's passive arming. Even if I had, I would have thought the mechanical key option was specific to locking the car with the mechanical key. What I learned is that it is not specific to that. Passive arming with an electronic key fob inside has the same result as the mechanical key option. Arming the Prius with a second electronic key fob (while leaving the first one inside) also has the same result as the mechanical key option. In all three scenarios, the electronic key fob left inside the car is temporarily disabled, which means that touching the exterior door handle will not unlock the Prime.

@DavidA seems to think that this mechanical key option is not a valid option because he can't find it in the owner's manual. DavidA is right in the sense that it is certainly odd that the mechanical key option is not mentioned in the owner's manual. However, it seems to me that it absolutely must be a purposeful feature of the Prime (and likely other Prius and other Toyota models). Why else would Toyota give you the option to purposefully lock a key in the Prime and thereby disable it while, at the same time, making it almost impossible to accidentally lock an electronic key fob inside the Prime?

I'd really appreciate any of you weighing in on this.

 

Yes, I saw that in the owner's manual, though thanks for mentioning that as it does figure in a bit here. However, I don't want this thread to get off-topic. I really want to know if others are aware of the "mechanical key option" that I described above (as told to me by my salesman at the dealership).

 

Yes, I know they can steal a Prime that doesn't have an alarm system even without the battery in the key fob by holding the key fob up to the start button, and that is relevant. However, they'd have to find the battery-less electronic key fob first (and know that holding it up to the start button would allow them to start the car). But it is worth exploring this potentiality you've mentioned:

If I were to use this mechanical option I've described above to lock my electronic key fob in the car, I would usually not bother to remove the battery from the electronic key fob unless I was going to be gone for a long time (days). In a Prime without an alarm system, removing the battery would offer some additional security, but not a great deal of it. However, in a Prime with an alarm system, removing the battery would offer substantial extra security. Why? Because the entire time the criminal was searching for the electronic key fob you hid in your Prime, the alarm would be going off. Also, without a battery in the electronic key, they could not disarm the alarm, which would mean that they could not drive your car away as the alarm's immobilizer would still be activated meaning your Prime could not be started, anyway.

Whether you have an alarm or not, and whether you were to remove the battery from the electronic key fob or not, just hiding the electronic key fob you leave in the car would provide, I believe, enough security in most parking situations. If you hide it well, which is not that difficult, it would be all but impossible for a car thief to find it unless they had hours to look for it. I won't say where I will hide mine in my Prius, but I can tell you that it would take a potential car thief hours to find it. On top of all of this, the potential car thief would have to know (or suspect) there was an electronic key fob in the Prime to even think to look for it. And why would a potential car thief even think to look for it? Why would they even think there was a deactivated electronic key fob in your Prime? I'm not going to leave it in the cup holder or the center console (although I might buy a used one off of eBay and not have it programmed in, and leave it in the center console to be easily found to cause even more confusion for a potential thief).

(Oh, and to address another point you or someone else made, I would never attach house keys to my car keys. Regardless, my house has no keys. It is alarmed, also, and opens via my cell phone or digital keypads.)

 

I visited my stereo/alarm installer yesterday and was asking him about this ability to leave your electronic key in your Prime and disable it by locking your car with the mechanical key (so you don't have to carry your electronic key with you). It is something he was aware of because it comes up when he installs alarms.

He showed me a nifty device called the RPS-Touch from Firstech car alarms (firstechllc.com). I'm linking a demonstration video video below. You mount this device to the inside of your windshield and operate it by touching the outside of your windshield to enter a four-digit code. It allows you to disarm a Firstech car alarm, which integrates with a Prius (and other cars) and unlocks your car. It should integrate fully with the Firstech alarm that will integrate with the Prime's smart key system.

With this, you don't need your electronic key or your mechanical key. Of course, you would have to hide it in your car, and that does raise the theft concerns that DavidA mentions above. I will have this installed so that I can sometimes leave my electronic key in my car (mainly when I'm at the beach). I will hide the electronic key very well and I don't believe it will be a theft risk as a potential thief would have to somehow guess that there is an electronic key in the car, and then find it while the alarm is going off. I think that a thief would almost certainly not be able to steal my Prime in those circumstances.

Firstech's alarms do currently work with other Prius models, but not yet with the Prime. My installer and I both spoke to them, and they are working on an update for the Prime and it should be available soon. Apparently they have to regularly update their software and hardware to work with increasingly complex cars because their alarms integrate with the car's systems so that you don't have to carry a separate key fob for the alarm system (it operates through your OEM Toyota electronic key fob).

As a side note, the people at Firstech told me that this ability to purposefully lock an OEM electronic key fob in your car with the car automatically deactivating it is an intentional feature that figures into their alarm design with the RPS, and they say it is an intentional feature from car manufacturers that is becoming more and more common in newer cars.