anomale

Hey guys here is the scoop. I have a 2006 Lexus GS 300 and about two weeks ago the key fob stopped working. I replaced two new batteries and nothing. I read up and found that if you place the fob over the start button and wait for the green light it would start. I have been starting the car like that ever since. Now here is the issue. Yesterday I went out to eat and when I was about to leave it would not start with the key over the button. I did not get a green light, nothing. after trying for about 10 minutes I got it to turn on the electrical system (basically it acted like it started but didn't) all the lights turned on and I saw the Check complete on the dash but the engine did not crank or start at all. Finally I disconnected the battery for 5 minutes and connected it again and was able to get it to start and drive home, now back to the same problem. anyone had this happen or know a way to fix it? I am a DIY'er and really don't want to go to the dealer and spend thousands (the key fob alone is quoted at $480)

thanks for the help

canatto

When was the last time you have the car battery changed? When the car battery is on its way gone it would show the borderline symptoms as you described, able to power up the electrical system but barely or not enough juice to crank the engine.

anomale

The Battery is 4 years old. Would a dying battery also cause the key fob to stop working? I tried again this morning and the green light is coming on and it can start. I'm starting to think it has something to do with the immobilizer unit but don't know enough about it to be sure. a few times when I put the fob up to the button I would hear the beep without a light on the start button but when I remove it and try again the green light comes on.

anomale

For the sake of trying I swapped out the battery and still can't detect the key fob. Put the old battery back and I am getting the green light when I place it over the start button and it starts but I don't know if I go somewhere if it will stop working again since it seems to be intermittent.

tatumjonj

Aren't most "immobilizer" units just the starter wire cut in half? That wouldn't cause any of the problems you're having. Describe your immobilizer in better detail. What does it disable? Does it simply keep the car from cranking?

tatumjonj

BTW, what you're describing certainly sounds like a car battery issue.

anomale

I am not sure what the immobilizer does (haven't read up on it) but there is something in the car that is in between the start button and the starter that detects the key and allows the car to start (I thought that was what the immobilizer did). that seems to be malfunctioning since I intermittently get the green light on the start button when the fob is placed over it.

as for the car battery I swapped out with a new one and still have the same issue.