I was able to program my GX into the garage opener but it deletes my Camry. As soon as I program the Camry it deletes the GX. Strange. I was able to have both cars when I had the ML320.

 

I have both of my cars programmed to open the same garage door openers. Either you are doing something wrong or your garage opener is the issue.

 

Each time you hit the program button on your opener you are setting a new code, so the other vehicle now has the old code, you either need to do both at the same time or program one of them via the door opener remote programming. Not sure about doing that method on the Lexus but I knew it works on my Corvette.

 

Not true for all openers. I have a Liftmaster with Rolling code remote and I have set up Homelink on my different cars without affecting other vehicle. I just followed Homelink instructions in owner manual and it worked first time. Vehicles were 2010 Sequoia, 2010 RX350, 2013 GS350 and 2014 GX460.

 

this is strange. I have added other cars before without having this problem. I even use a different remote to learn to code for each car. As soon as I add one car the other gets deleted. I have a Genie btw.

 

I think I found the root cause of my problem. I have read that the system I have has a limited number (7) of devices it could remember. This would explain why this happens.