Disabling Unlimited Key Mode

WARNING: This page is about a different car, the 2005 Lincoln LS. However, it is still accessible from the selected car via links, so may be relevant.

Using a diagnostic tool, select instrument cluster from the menu. Follow SECURITY ACCESS to obtain security access. For additional information, refer to ANTI-THEFT SECURITY ACCESS in this article.
Select: DISABLE UNLIMITED KEY MODE.
Select: IGNITION KEY CODE ERASE and RESET SERVICE BIT, if applicable.
Disconnect the diagnostic tool and turn the ignition switch to OFF.
Program in 2 keys to enable the vehicle.
Program any additional keys using either Key Programming Using Two Programmed Keys or Key Programming Using Diagnostic Equipment in this article.