Outside Air Temperature Display

The Ambient Air Temperature (AAT) sensor is hardwired to the IPC through separate input and return circuits. The IPC provides a reference voltage to the Ambient Air Temperature (AAT) sensor and monitors the change in voltage resulting from changes in resistance as determined by outside air temperature. The IPC filters the ambient air temperature input and sends the outside air temperature data message to the FDIM through the APIM over the Infotainment Controller Area Network (I-CAN) or to the FCDIM over the Infotainment Controller Area Network (I-CAN). The IPC is programmed to update the displayed temperature at different rates depending on several criteria to prevent false temperature displays due to a condition known as heat soaking. Heat soaking is where the outside air temperature is hotter in the location of the Ambient Air Temperature (AAT) sensor than the actual outside air temperature.

The IPC uses the last displayed temperature reading, engine coolant temperature and length of time the engine is off to determine how the display is updated. The IPC stores the last temperature reading at key off and then compares the value against the current temperature reading. When the current temperature reading is below the stored temperature reading, the engine has been off for 2.5 hours or the engine coolant temperature is below 45 °C (32 °F), the IPC displays the current outside air temperature as measured by the Ambient Air Temperature (AAT) sensor.

If the IPC fails any of the above criteria, the display is updated according to the following table: