| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. | 
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. | 
| • | Diagnostic Procedure Instructions provide an overview of each diagnostic category. | 
Circuit  | Short to Ground  | Open  | High Resistance  | Short to Voltage  | Signal Performance  | 
|---|---|---|---|---|---|
IAT Sensor 2 Signal  | P0097  | P0098  | P0116  | P0098*  | P0098, P0116  | 
IAT Sensor 2 Low Reference  | --  | P0098  | P0116  | P0098*  | --  | 
*Internal ECM or sensor damage may occur if the circuit is shorted to B+.  | |||||
Circuit  | Short to Ground  | Open  | Short to Voltage  | 
|---|---|---|---|
Operating Conditions: Ignition ON or Engine Running Parameter Normal Range: -39 to +120°C (-38 to +248°F)  | |||
IAT Sensor 2 Signal  | 139°C (282°F)  | -40°C (-40°F)  | -40°C (-40°F)  | 
IAT Sensor 2 Low Reference  | --  | -40°C (-40°F)  | -40°C (-40°F)  | 
The intake air temperature (IAT) sensor 2 is a variable resistor that measures the temperature of the air in the engine intake manifold. The engine control module (ECM) supplies 5 volts to the IAT sensor 2 signal circuit, and a ground for the IAT sensor 2 low reference circuit. The ECM continuously monitors the IAT sensor 2 signal voltage for an excessively high or low voltage, or a voltage signal that is not in correlation with the engine coolant temperature (ECT) sensor.
| • | The ignition is ON or the engine is running. | 
| • | The DTCs run continuously when the enabling conditions are met. | 
The IAT sensor 2 is greater than 148°C (298°F) for greater than 1 second. This is equal to or less than 0.10 volt on the IAT sensor 2 signal circuit as measured by the ECM.
The IAT sensor 2 is less than -39°C (-38°F) for greater than 1 second. This is equal to or greater than 4.8 volts on the IAT sensor 2 signal circuit as measured by the ECM.
| • | DTCs P0097 and P0098 are Type B DTCs. | 
| • | Diesel particulate filter (DPF) regeneration is inhibited. | 
DTCs P0097 and P0098 are Type B DTCs.
| • | If the engine has sat overnight, the IAT sensor 2 and the ECT sensor values should display within 15°C (27°F). | 
| • | High resistance on either the IAT sensor 2 signal circuit or the IAT sensor 2 low reference circuit could set this DTC. | 
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Control Module References for scan tool information
| ⇒ | If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM. | 
| ⇒ | If greater than the specified range, test the signal circuit terminal A for a short to ground. If the circuit tests normal, replace the ECM. | 
| ⇒ | If less than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM. | 
| ⇒ | If not within the specified range, replace the IAT sensor 2. | 
Important: A thermometer can be used to test the sensor off the vehicle in heated water.
| ⇒ | If not within the specified range, replace the IAT sensor 2. | 
| • | Control Module References for ECM replacement, setup, and programming | 
| ⇒ | If the Soot Mass value is less than 30 grams, perform the. Diesel Particulate Filter (DPF) Regeneration Enable. | 
| ⇒ | If the Soot Mass value is greater than 30 grams, perform the. Diesel Particulate Filter (DPF) Service Regeneration. |