I am trying to program a new key ( I have already successfully added a key a few months ago) with a techstream. It fails on step one now. The one key that works doesn't have anything happen when I try to interact with the RFID on the start button. When a battery is in, it operates as intended. I have replaced all the batteries already with no luck. Any ideas? Thanks

 

I don't really understand your question. What battery are you talking about?

 

The fob batteries in this case.

 

I do not have a LS460, but
on my LS430 it comes with 3 keys and has room for 1 more.
after that you have to delete an old key to add a new one
could it be that simple?

 

That is a good advice, you should be able to see how many keys were registered with the car.

 

If I'm understanding this correctly you have a key that isn't recognized by the car when held against or pressed on the start button when the battery is removed from the fob? are you working with oem or aftermarket key fobs?
I tried that test when I bought my 460 and both keys started the car with the batteries removed when used on the start button. Did you erase all existing keys except for the original master before programming the new key, if not you could try the process again. I think you can do 5 total because I did 2 fobs and 1 card key and still have 1 or 2 spaces left.