Clutchless

I already searched and found little on this issue.

We have a CT200h and last week bought a used 2010 RX 350 with 21,552 miles. Now we often get key not detected in both vehicles when the remotes from both vehicles are in one or the other. It appears they RX remote is interfering with the CT remote and vice versa.

I tried to reach my dealer but my SA was out and no one else was around. I will try them later, but wanted to get more input from members.

Evitzee

Not unusual for key fobs to be tricked by stray radio interference which appears to be what is happening to you. Not much you can do about it other than to not have both keys in the same vehicle at the same time.

corradoMR2

I have a 13 RX and 11 CT and so far no interference but it's only been 2 days I have the new RX. Will keep an eye out for this.

Clutchless

Finally got hold of the dealer. There is a service bulletin for the CT regarding not recognizing the electronic keys. They said when they fix it on the Ct that should resolve the problems with both vehicles.

chuckGS350

I ran into this TSB today.
The TSB is for CT, 20011/2012 RX350, GX460, and a few more models, but not GS regarding this Key Not Detected issue.

My wife drives a 2011 RX350 and she carries my spare GS key fob in her key chain, but
never sees "Key Not Detected" message on the multi-info display.
But soon as her sister is in the car with her 2012 RX350 key fob in her purse, then here comes the Key Not Detected message.
Sometime my wife had to put the key fob near the Start button to start the car. That's exactly what the TSB calls for. And I was joking about her sister's smart key interference.
It turns out to be true after reading the TSB.
L-SB-0011-12

satnav

Also I noticed if placed next to my iPhone with Bluetooth on it will not work and will tell me the key is not detected.

ELITech

I have not read through the TSB, but one fix is that Lexus will repalce the Certification ECU and new keys for either vehicle.

We had this issue actually with a customer's Lexus LS smart key and a smart key to their Toyota. The Toyota smart key would frequently interfere with the smart key for the Lexus and cause a no-start or key not detected issue.

While these occurrences are rare, there are only a limited number of frequencies that Lexus/Toyota can use...

So when the problem occurs, the dealer typically can contact our Support department who will send a new certification ecu and keys that are known to be of different frequencies so that interference doesn't occur anymore...

chuckGS350

I read the TSB. It calls for the replacement of the Door Conrol Receiver and new keys.

Clutchless

When they did the TSB repair on my CT200h they replaced the FM transmitter with an AM one. Apparently the issue is FM frequencies that are too close together causing interference that leads to the key not detected issue.