IA Key
WARNING: This page is about a different car, the 2015 Lincoln MKT. However, it is still accessible from the selected car via links, so may be relevant.
The IA key incorporates both the PATS and the RKE transmitter functions in a single device. The IA key must be located inside the vehicle for engine starting. When the IA key is activated it sends out a frequency signal that is received by the TPM module. The IA key also contains a key blade that is used to enter the vehicle as a backup.