Intelligent Access (IA) Key
WARNING: This page is about a different car, the 2013 Ford Explorer. However, it is still accessible from the selected car via links, so may be relevant.
The Intelligent Access (IA) key receives the low frequency signals from the Intelligent Access (IA) antennas. When the Intelligent Access (IA) key is activated by one of the low frequency signals, it sends out a high frequency signal that is received by the TPM module. The Intelligent Access (IA) key also contains a key blade used to enter the vehicle as a backup.