Set Condition
WARNING: This page is about a different car, the 2014 Fiat 500c and 2014 Fiat 500. However, it is still accessible from the selected car via links, so may be relevant.
The PCM compares the ambient, engine coolant and intake air temperature sensor values. If engine coolant and intake air temperature sensors agree with each other but ambient air temperature does not agree, the ambient air temperature sensor is declared as irrational. Two Trip Fault. Three good trips to turn off the MIL.