how it work 556u bypass module

um, the whole point of the 556u box is to amplify the key's transpnoder signal and transmit it to the key cylinder receiver via the loop ring.

If you don't have a key in the box, then it will not work.

thank you very much for the fast reply.  I bought the 556u because I was told this one does not require the key.  when I call directed the rep was very unhelpful because it was not their brand alarm I was using.  I ask the rep how does the module recognize the key? do I just have to put the key in the ignition for it to learn? and he replied yes.  He should have told me at that moment it have to be in the module itself. 

I am going to put my spare in there now and give it a try

thanks

nice work.

You know, if you don't want to leave a key in your car like that, you can obtain a bypass module that truly does NOT require a key -- something to think about for the future.