The intake air temperature (IAT) sensor 2 is a variable resistor. The IAT sensor 2 has a signal circuit and a low reference circuit. The IAT sensor 2 measures the temperature of the air at the engines 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. When the IAT sensor 2 is cold, the sensor resistance is high. When the intake manifold air temperature increases, the sensor resistance decreases. With high sensor resistance, the ECM detects a high voltage on the IAT sensor 2 signal circuit. With lower sensor resistance, the ECM detects a lower voltage on the IAT sensor 2 signal circuit. The ECM continuously monitors the IAT signal voltage for an excessively high or low voltage, or a voltage signal that is not in correlation with the mass air flow (MAF)/IAT sensor.

DTC P0097 and P0098 run continuously within the enabling conditions.

P0097

The IAT sensor 2 is more than 148°C (298°F) for more than 1 second. This is equal to or less than 0.24 volt on the IAT sensor 2 signal circuit as measured by the ECM.

P0098

The IAT sensor 2 is less than -39°C (-38°F) for more than 1 second. This is equal to or more than 4.86 volts on the IAT signal circuit as measured by the ECM.

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Electrical Information Reference

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Important: Perform this verification procedure only if the ignition has been OFF for 8 hours or more.

1. Ignition ON, observe the scan tool IAT Sensor, IAT Sensor 2, and ECT Sensor parameters. The reading should be within 8°C (15°F) of each other and also the ambient temperature.
2. Engine running, observe the DTC information with a scan tool. DTCs P0097 or P0098 should not set.
3. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

1. Ignition OFF, disconnect the harness connector at the IAT sensor 2.
2. Ignition OFF, allow sufficient time for the control module to power down. Test for less than 5 ohms of resistance between the low reference circuit terminal B and ground.

⇒	If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.

3. Ignition ON, verify the scan tool IAT sensor 2 parameter is less than -39°C (-38°F).

⇒	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.

4. Install a 3A fused jumper wire between the signal circuit terminal A and the low reference circuit terminal B. Verify the scan tool IAT sensor 2 parameter is greater than 130°C (266°F).

⇒	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.

5. If all circuits test normal, test or replace the IAT sensor 2.

Static Test

1. Ignition OFF, disconnect the harness connector at the IAT sensor 2.
2. Measure the resistance between the signal terminal A and the low reference circuit terminal B and compare the value to the Temperature Vs Resistance table. Verify the resistance is within 5 percent of the specification. Refer to Temperature Versus Resistance .

Dynamic Test

Important: A thermometer can be used to test the sensor off the vehicle in heated water.

1. Test the IAT sensor 2 by varying the sensor temperature while monitoring the sensor resistance.
2. Compare the readings with the Temperature Vs Resistance table and verify that the resistance is within 5 percent of the specification.

⇒	If not within the specified range, replace the IAT sensor 2.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.