RTT Indicators: Frost
WARNING: This page is about a different car, the 2018 Ford EcoSport. However, it is still accessible from the selected car via links, so may be relevant.
The frost RTT indicator is used to inform the driver that the outside ambient air temperature has fallen below 4 deg. C (39 deg. F), indicating potential icing conditions. The IPC receives the outside air temperature message from the GWM over the HS-CAN3. The GWM receives the outside air temperature message from the HVAC module over the MS-CAN.