Question:

Just took delivery on a 2000 XLS Explorer, and with 50 miles now on the odometer I like it.  I’m curious about how the ignition key with the chip hooks into the electronic system.  As near as I can tell from looking at the key, there is no place for a second contact to be made with it.  The part that is inserted seems to be solid metal, and the "handle" part is plastic.  My basic understanding of electrical/electronic gadgets is that they require TWO connections, and with a DC system one would be positive, and the other negative.   Is there a second connection to the key I have not noticed? If no second connection, how does it work? Is there a battery inside the key that will eventually need to be replacaed?  I can see a small "door" that I assume can be pried off for such a purpose. Any insight appreciated.  Many thanks. — CWLee Former slayer of dragons; practice now limited to sacred cows. Believing we should hire for quality, not quotas, and promote for performance, not preferences.

Response:

The transponder inside the key is "charged" by the same radio frequencies that communicate with the key.  RFID it’s called (Radio Frequency Identification).  A transciever mounted around the ignition lock transmits a signal when the key is inserted.  The transponder within the key is programmed to respond with a certain "code", and once the "handshake" is made, the switch in the ignition is activated so that you may start your vehicle.  If the connection is not made, the ignition is not electrically switched, and is disabled.  There are millions of possible code combinations set to some certain algorithm, so the possibility of it being duplicated is very very slim, and if it was, it could take days (your common theif won’t stick around for more than 2 minutes). The new 2001 Explorer (when it finally is launched) will sport the latest i-PATS system similar to that found in the 2000 Taurus/Sable which features a new chip, capable of billions of codes.  Even more security. JH 95 EB – 115K miles John G. Holt Mechanical Engineering University of Wisconsin – Milwaukee College of Engineering and Applied Science www.uwm.edu/~holter88

– Hide quoted text — Show quoted text -> Just took delivery on a 2000 XLS Explorer, and with 50 miles now on the > odometer I like it.  I’m curious about how the ignition key with the > chip hooks into the electronic system.  As near as I can tell from > looking at the key, there is no place for a second contact to be made > with it.  The part that is inserted seems to be solid metal, and the > "handle" part is plastic.  My basic understanding of > electrical/electronic gadgets is that they require TWO connections, and > with a DC system one would be positive, and the other negative. > Is there a second connection to the key I have not noticed? > If no second connection, how does it work? > Is there a battery inside the key that will eventually need to be > replacaed?  I can see a small "door" that I assume can be pried off for > such a purpose. > Any insight appreciated.  Many thanks. > — > CWLee > Former slayer of dragons; practice now limited to sacred cows. > Believing we should hire for quality, not quotas, and promote > for performance, not preferences.

Response: