dngo27

does the remote just pop open? i just looked at my fob, no indents to pry open. i might as well replace my battery now too. its been about 16 months for me.

dngo27

check that, theres an indent within the key slot. you can use the metal key end to pop it open.

gshb

hey guys, if you keep your key in your pocket all the time and dont use the buttons, the battery will last you years. if you always use the fob to lock/unlock/trunk then you can wear it down after 15k miles. when the key is dying you have to put the key fob right up to the start button to start the car. if you stop to park, but leave the car running the car may say it cant find the key. this is why youre able to lock the fob in the car.

IS_250

iTrader: (2)

im not so sure about that. hardly ever used the buttons on my keyfob and the OEM battery only last me 1.5 years. i have noticed that if the key is in the car the light on the keyfob will flash every few minutes. im assuming that the car and the key constantly sends a signal to each other to make sure the car can detect the keyfob.

lobuxracer

iTrader: (2)

You are exactly correct. The documentation says if you plan to store the car more than 21 days, you should ensure the key is not stored within 1 meter of the car to allow the power saving feature for the car's battery to work. The same is true for the key. There is a whole section in the New Car Features book about this.

ecr527

I just started having problems with this starting the other day. First, my doors would not always lock when I press the button on the door handle. Today, I got into the car going back to work at lunch time and when I went to start the car, the display read "key not detected". I stopped by Radio Shack (they carry the battery, but it's only available online) and a local Walgreens and they both did not have this battery. I ended up going to the dealership where the sell the battery for $4.00. Not a bad price considering I found them online for $2.00, but then it cost another $2.00 for shipping. Since JM Lexus doesn't close until 10 PM, I decided to stop in today after work and I purchased the battery from them. They even installed it for me. I've had my car for about 1 1/2 years.

ba-b4

no matter what it shouldn't last such a short time.. my other car's fob has lasted me 6 years without even ONE battery change and is still going strong. It shouldn't matter if you use the buttons or not.

jackblack7

But your other car fob is only "on" when you push the button. The Lexus fob is always on.

sinister2c

no the lexus fob is not always on. it only activates when you touch the sensor on the back side of the door handle. once you do that the car sends a signal to the fob and it goes threw its "hand shake" routine to verify that the fob is programed to the car.

Shoyuu

Good reminder

Bichon

You're mistaken. Like any active RFID device, the Lexus smart key is continuously powered. Power draw while waiting to be read is fairly negligible, but when transmitting is much higher.

If you watch the red light on the key as you approach the car, you'll see that it starts flashing (once every 10 seconds or so) when you are several feet away. If you are approaching from the side, the puddle lights are illuminated after the first flash. All this happens long before you touch the door handle.

wolverine

iTrader: (9)

I replaced my battery a couple months ago when the little screen on the instrument cluster told me that it was low.... i wonder why you didnt get the message?

lobuxracer

iTrader: (2)

The documentation says its sending and receiving every 250msec once you are inside one meter. Even at close range, that's a pretty healthy power drain.

ba-b4

so when you're closer than 1 meter then the key is constantly sending and receiving? So outside of 1 meter though it should be completely off then right? Man if this is the case I'd prefer to just use the old fashioned regular fob and key system than always having to replace these batteries.

Bichon

No, it has to be powered so that it will know when the car is interrogating it. Your cell phone won't ring if you have it turned off, right?

If the battery dies, there is also a failsafe "passive" mode. When you hold the fob directly in front of the start/stop button, it will be powered by induced current.