When the battery in the Intelligent Key dies it looks as if you are supposed to put the Intelligent Key fob (not the key) into a slot that is located to the left and down of the steering wheel. My question is if the battery is dead how does putting it in this slot help. I would understand if the slot had some way of powering up the key fob but I don’t see any metal contacts or ports on the key fob.

Is it just that, if your fob dies, that you have to use your (specific) key (pulled out from the fob) to open the door and any key fob put in to the slot will start the car? How is the car going to read/recognize the fob if the battery is dead?

 

Well... if the battery is dead, how are you planning on starting the car to begin with?

 

Sounds like it has 2 types of RFID - active and passive.
So the port in the dash probably reads the non-battery powered ID.

Just a guess.

 

I meant if the Key Fob battery was dead not the car battery.

 

Sorry, I misread it.

I think that when you stick the fob into the port, a certain part is pulled away exposing metal contacts....

 

No hard contacts, the port is meant as a backup if/when your remote battery dies. It will allow your car to start.

 

Well then, I guess like with every other fob - if the battery dies, you need to replace it.

 

Sounds like it has 2 types of RFID - active and passive.
So the port in the dash probably reads the non-battery powered ID.

Just a guess.

 

In the Lexus IS, when the keyfob battery dies, you can hold the fob against the start button, and after about 5 seconds, it lets out a little beep. You can then start the car.

There is something in the fob which can be read if held very closely to the device that does the reading.

The G must have this in it's little fob hole where Lexus cose to stick it near the start button.

.... I said "Fob Hole"

 

By putting the fob in the slot, you're putting an immobilizer chip near a sensor. The ignition normally gets the immobilizer signal by RF from the fob.

 

Ok. I'll go into more detail...

The system works on RFID (Radio Frequency IDentification).
The ACTIVE radio uses the battery to transmit a unique signal to the CAR.
Battery = range. 2 to 3 feet.

The PASSIVE chip (no battery) uses an antenna in the FOB HOLE.
Energy supplied by the car battery.
So when the battery goes out, it can still read the ID#.

Passive = Same technology used in security systems at the store when you exit.

 

why did the dealer tell me to charge the key fob once a month for 20 minutes using that little slot?

 

Wow, now that's a new one! Dealers will say anything sometimes... I doubt your fob will "recharge" in the slot especially since the battery is just a standard cell, not a rechargeable one...

 

astonished that my 'intelligent' key has not been sent through the washing machine yet.

 

My dealer told me the same comments above that it is a proximity thing and even if the fob is dead, the proximity of the fob (in the fob hole) to the engine, ignition, or whatever will allow the car to start.