How does a PASS-Key III work?

Question

I'm about to buy a 2003 Caddy that has a PASS-Key III. I'm not sure how it works?

Answer 1

Looks like the regular key my dad's car has
check it out ..........scroll towards the bottom
http://hometown.aol.com/ablelocks/page1.html


apparently its just a key programmed to tell the difference, whether its driver 1 or driver 2, the owners manual should tell you how to set it up exactly
my dad has the same thing
it comes in all the models apparently
http://www.cadillac.com/cgi-bin/SearchServer.exe?method=mainQuery&db0=Cadillac_All&numresults=100&querythreshold=10&batchhits=25&refresh=refresh&QuerySummaryCB=querysummary&query=Pass+Key+III

Answer 2

The Pass-key III system uses a low-power transponder mounted in the head of the ignition key. When you insert the key into the ignition a receiver around the key switch get the transmitted signal from the key. If the system doesn't get the right signal, it doesn't allow the vehicle to start.

It's a very effective anti-theft system, since it's impossible to start the vehicle without the right key. It does make it more expensive to buy additional keys or replace keys; you can't just have a new one cut at the hardware store.