IG KEY : OFF , Engine : OFF
Disconnet IAT sensor connector(C55).
Measure resistence between terminals4 and 5 of the IAT sensor connectorC55.
Specification :

Temperature ℃(℉)  | -40(-40)  | -30(-22)  | -20(-4)  | 0(32)  | 20(68)  | 60(140)  | 100(212)  | 110(230)  | 120(248)  | 
Resistence(kΩ)  | 45.3  | 25.6  | 15.1  | 5.8  | 2.5  | 0.6  | 0.19  | 0.16  | 0.13  | 
Voltage(V)  | 4.48  | 4.34  | 4.12  | 3.46  | 2.57  | 1.06  | 0.39  | 0.34  | 0.27  | 
(Pull up resistance is Approx. 2.2kΩ and above specification’s error range is 2~3%.)
Is IAT sensor normal?
YES
IAT sensor is OK.
Possibility of defective ECM.Temporarily test with a new ECM and check for proper operation.
If problem is corrected, replace ECM and go to "Verification of Vehicle Repair" procedure.
NO
Test with a new IAT sensor and check for proper operation.If problem is corrected, replace it.
And go to "Verification of Vehicle Repair" procedure.