Transponder Key: Description
WARNING: This page is about a different car, the 2004 Dodge Grand Caravan, 2004 Dodge Caravan, and 2004 Chrysler Town & Country. However, it is still accessible from the selected car via links, so may be relevant.
The Sentry Key Remote Entry System (SKREES) uses a transponder chip that is integral to each ignition key to communicate with the Sentry Key Remote Entry Module (SKREEM). Ignition keys are supplied with the vehicle when it is shipped from the factory. The transponder chip is undermolded within the head of the key.