Backward compatibility for Bluetooth?

I have a 2006 Lexus RX400h which came equipped with Bluetooth. My old 3G DroidX smart phone worked fine with the car’s Bluetooth, but that cell phone eventually died. I bought a new cell phone - a 4G model (MotoX) and discovered that it is not compatible with my car’s Bluetooth. It appears that none of the newer phones are backward compatible with the 2006 technology. Lexus does not offer the option to update the car’s Bluetooth. They suggest I buy a new car…right!
But, here is the strange part…sometimes, my new phone (MotoX) suddenly starts working with the car’s Bluetooth. Sometimes it will work for days and then stop working. Sometimes it half works - meaning that it connects and lets me use the car’s touch screen to dial and hang up, but the sound won’t come out of the car’s speakers - it only comes out of the phone.
I have tried all kinds of changes in the environment (radio on, radio off, etc.) but I can’t figure out what causes the compatibility to appear and disappear. Any guidance would be much appreciated.

3G/4G is the wireless technology that enables you to use the internet with your cell phone. It has nothing to do with bluetooth. Your new phone is defective and whoever told you it wasn’t compatible with your cars bluetooth is full of it.

Maybe your car is trying to tell you that you should not talk on the phone and mess with the touch screen while you are driving.

Welcome to the wild world of Bluetooth compatibility. I might try calling Crutchfield to see if they have a Bluetooth attachment that might solve your problem.

I was told that the MotoX is not compatible with my car by Lexus. They have a website that lists the compatible phones.

All that means is that they have not tested your phone with that car. This doesn’t necessarily mean your phone will definitely work with your car, but it doesn’t mean it won’t either.

We just gave up. The salesman worked on our 2012 Acura for a couple hours trying to get our blue tooth going and gave up. Then our physician technically savy son worked on it a couple hours too and gave up. So we just don’t use it. I’ll admit I don’t know anything about it but think maybe buying a new car is the best and easiest solution. Then of course the sale would be contingent on getting the cell phone to work. Sweat, delay, sweat.

My MotoX wasn’t listed as compatible with my 2014 Subaru either, but it works. I could not get it to work but my tech savy son had it working in about 5 minutes. He did something with the password on the phone to get it to work. There were no instructions for this in the phone’s owner’s manual or in the cars owner’s manual.

It’s not the bluetooth that is the problem, it is in the security of the phone.

@keith: It’s not likely the security if it will pair with the car. I have a friend whose Samsung phone is not compatible with his new Subaru… so he traded his wife for her iPhone. She got the better deal. My old DroidX would work fine with my 2006 Chrysler. My Droid Razr would receive but not place calls. My Samsung phone I haven’t tried yet, as I rarely use the integrated system. It’s likely the firmware on the car needs updating, but unless someone takes it upon themselves to rewrite the Bluetooth drivers, it’s unlikely that it will ever work properly for the OP.

It’s interesting that while there are international standards that are supposedly adhered to for compatibility, these things happen all the time. I work in the tech sector and see this kind of thing every day.