2014 Camry Door Control Receiver
 

My 2014 Camry Door Control Receiver stopped working. I say that since none of my keys work with it. I've used Techstream to register new keys when it worked so I know how that is done. After my receiver went bad I tried to re-register my keys. The process goes as expected and Techstream says the keys are registered but in diagnostic mode they keys are detected as working but not registered! Needless to say they don't operate the doors either. I bought two used receivers from eBay and both are giving me the same result. So my questions are:

1. Are all these receivers bad and do I just need to keep trying to get a good one?
2. Is something else wrong somewhere that has nothing to do with the receiver?
3. Any suggestions on how to find out without buying another receiver?

Might read appropriate threads at Toyotanation.com. Toyota tends to have very similar systems between models thus info for one model might help with another.