From the Ross-Tech Wiki:
16496/P0112 - Intake Air Temperature (IAT) Sensor 1 Circuit (G42): Low Input
Possible Symptoms
* unknown
Possible Causes
* Grounded circuit in harness
* Improper harness connection
* G42 faulty
* Control Module faulty
Possible Solutions
* Check wiring and connections
* Check / Replace G42
* Check / Replace Controle Module