TPM Module
WARNING: This page is about a different car, the 2016 Ford Expedition. However, it is still accessible from the selected car via links, so may be relevant.
The TPM module is a receiving antenna that receives high frequency signals. When a remote start request is initiated from the Passive key the TPM module receives the signal and communicates the remote start request message to the RFA module. The RFA module transmits the message via the MS-CAN to the BCM to initiate a remote start event.