Hello, yet another issue with my first Lexus, 2007 rx350. This time the key transmitter have stopped unlocking the doors after a day or two of reprogramming, sometimes it randomly worked one day and then stopped, even bought a brand-new key, programmed it by a locksmith and it's the same thing. Stopped opening the doors.
Has anyone experienced this? Can it be an antenna or some module responsible for receiving the signal from the transmitter? Any suggestions? Thanks

 

visit Lexus/Toyota dealer

 

How many keys do you have?
Are all your keys having the same problem?
Why was the key reprogrammed, anyway? What was the original problem?

 

Now I have two keys. I bought a new oem key thinking that the old transmitter just quit, the new key worked just one day.
Both keys (door lock transmitters) are not working now.
Someone suggested to me it may be bad ecu immobilizer.

 

Sounds like it wasn't properly programmed into the computer. You need the Techstream software, which a dealer would have. Unfortunately, that might be costly.

I'm sorry, a simple fix does not seem likely unless you have and are somewhat familiar with Techstream and programming keys.
Also, I'm not aware of bad immobilizer units being a common issue.

 

but the thing is that the new key is doing exactly what the old key (which came with the car) was doing; the doors locking system only randomly works

 

use techstream and program a genuine new key. cloned keys give you problems like this.