Backup Transceiver
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 backup transceiver is used as a backup device. If the vehicle fails to start conventionally, a passive key can be placed in the backup starting location to allow the vehicle to start. The backup transceiver activates any passive key that is placed in the backup starting location. When activated by the RFA module, it sends out a signal to activate a passive key. When the key activates, it sends a signal back to the transceiver which is then sent to the RFA module.