I think we have a chicken and an egg problem here. If the battery goes into an "off" position, it isn't going to be able to recognize the keyfob to open the doors? If it does, then it isn't an "off" button.

 

Correct me if I'm wrong but if the 12V battery goes dead you're stranded unless you can jump the battery right? Assuming my dealer is correct and the battery will go dead in 2 weeks (as my dealer indicated - might be wrong though), then it is an issue for some of us that might have the car parked in an airport without being turned off for some time.

 

I also thought of that. Here's my reasoning (as warped as it may be). The Smart Key entry can be a passive device, similar to the RFID tags that are being incorporated in products. The TCH has to transmit a signal at all times in order to read the Smart Key, hence draining the battery. I'm assuming this is the case because if the key fob were transmitting all the time the battery in the fob would die very quickly.

However, when you press the unlock button on the fob it will actively transmit a signal to the TCH. The TCH in turn does not need to be transmitting a signal as it does for the Smart Entry. It just needs to receive the signal which consumes much less, if any power.

Don't know if that's how it works. Just makes sense to me.

Disclaimer: I'm not an engineer, I just stayed at a Holiday Inn Expres... Oh wait, I am an engineer. Never mind.

 

Ok, I can buy your theory where it goes into a "listen" only mode which is considerably less battery intensive than constantly transmitting.

Now....as a fellow engineer...who's going to test this theory? .

 

You mean "don't drive my TCH for two weeks"? I'll let you do it.

 

It's not the battery that goes into the "off" position, it is the Smart Key Active Radios that go into the off position. After two weeks if the active radios do not detect a fob, they shutdown. The normal passive receiver remains powered. When a fob is used manually to unlock the doors (ie the passive receiver receives an unlock request), the Smart Key active radios power up again.

 

I asked the dealer how to do this and the tech printed out a page titled Procedure to Disable Smart Key. I've tried it and it does work!

Start with the engine off, driver's side door closed and unlocked. The door to be opened and closed is the driver's door. You have up to 5 seconds between each step.

1. Unlock the car once with the unlock button on the remote
2. Open the door
3. Unlock the door twice with the remote
4. Close and open the door twice, leaving the door open
5. Unlock the car twice with the remote
6. Close and open the door once!
7. Close the door and the car will beep twice. Now the Smart Key has been disabled. Repeat this proceedure to enable the Smart Key, and the car will beep once when enabled.

If the car does not beep after finishing the proceedure, you took too long between a step. You can still open the car with the remote. But the button on the door handle, and grabbing the door handle to unlock the car will no longer work.