Striker98

Hey everyone just wondering if the key fob ever stops working besides the battery dying. Just mine were giving the low battery warning so I replaced the batteries but now a couple weeks later I’m still having issues of the doors not unlocking or the car recognizing the key to start the car. I have swapped different batteries and not cheap brands and re installed and still having same issue so just wondering if the fob could be wearing out. Any other suggestions?

Sasnuke

Couple things you can check first:

1. If you cover the remote face with one hand so it's in the dark, and press any of the buttons with the other hand, can you see the red light at the top right next to the Lock button? Is it nice and bright?
2. If you approach the driver's door with the key on your person, and touch the inside of the handle, will the door(s) unlock?
3. What message does it say when you try to start the car and it doesn't? And ultimately how do you end up starting it?

mcomer

Isolate the cause(s), does the fob unlock the passenger side correctly?
Does the second key work correctly? (Is the second key inside the car?)
Does your key ring have another keyless style fob held nearby?

Striker98

So the door won’t open by me grabbing it. Even using the buttons it sometimes doesn’t open or lock. I do see a red light come on the fob when using it. The second set is inside and I have been using but they too starting to have same issue. So when I get in the car it says key fob not detected on the dash. Eventually after trying a few times it finds it and the car will start.

Sasnuke

It still sounds like a battery issue in the remotes.
I know you said you saw the red light, but it has to be bright. I realize bright is subjective since I can't see it.
If you see the light, then at least the battery isn't completely dead.
If it doesn't find the key in the car when starting, then hold the Lexus emblem side of the key up to the Start button and at the same time press the Start button...it should start immediately.
The Start button will actually trigger the transponder in the key so that it can be detected.
The car sees the keys using oscillators...there is one in the drivers door that sees the key when it's outside (as you approach the car). Once you're in the car then it switches to the interior oscillator to see the key inside the car (there is one for the trunk too)
So if the Smart Entry and push Start both aren't working, then most likely its the key, as that is common to both systems.
I know you said you replaced the batteries with reputable brands, but maybe they're just duds. Maybe try another battery.
Also double check there are no other Smart keys of any kind inside the vehicle.

mcomer

The second set is inside... if the second fob is inside when you try to unlock by touching the door handle
it will not unlock. Pressing the outside unlock button will work but the door sensor will not.