Keeping an emergency key & fob hidden under car

I've never figured out how to leave the spare key fob in the vehicle and lock the door. It screams at me when I try.

 

The only reasonable way to do it is to buy a new fob from the dealer and they will program it off your existing fob and will setup the car's system for it to work. To keep it outside the car in a magnetic holder you need to have it shielded in metal well enough that the car does not pick it up or it can cause a current draw on the battery.

It is possible to use a fob without a battery which would make it easier to place somewhere accessible outside the car. But you then have to use the mechanical key to get in and place the fob right on the Power button to start the car. In this case you could simply keep the mechanical key outside and have the unpowered fob inside.

 

Don't know if this applies to the 2015 V, but on my 2017 you can turn off the signal from the key fob:

 

I think @rjparker was not concerned about the key fob battery. Have you ever noticed that the dome lights come on in the car before you are close enough to touch it? The car also powers up the brake booster pump and who knows what else at the same time. I don't know why the brake booster pump would "wake up" just because you are close to the car; it just does it. I just know it is very very important to place all key fobs as far away from the car as possible when doing a brake job.

Now imagine that you somehow attach your spare key fob with a battery in it somewhere on the car that isn't well shielded, and leave it for a few days. The dome lights might stay on and/or the brake booster pump might draw current. You could possibly run down both the 12 volt and the Hybrid batteries that way. You could have a very expensive brick when you return to your car.

Removing the battery from the hidden spare key solves this problem. Use the mechanical key to open the door. Even without a battery in it, you can start the car by holding the fob against the "start" button (thanks to RFID).

Oh, and I think a good automotive locksmith can activate a new fob for less than the dealer, which is still pretty darn expensive.

 

Is that a 'v' thing? My Liftback doesn't trigger the brake booster until the driver door is opened. And the door triggers this even when the fob is nowhere nearby.

I thought it was best to disconnect the 12V battery.

None of this should affect the hybrid battery. It is disconnected until the car tries to go "READY", which should happen only with deliberate attempts to start the car.

I definitely agree here.

 

I keep the extra door key in my wallet. The additional fob, however is hidden inside the car with no battery installed.

You could hide the insert door key outside, if you want.

I removed the black plastic tab from the insert key, so that it can be carried flat in the wallet.

If you have at least one functional key, you can program another NEW Key with Techstream. Just be sure you don't connect to WiFi, or Toyota will ask you for a dealer ID and a password.

This video might also help.