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 measures the temperature of the air at the engines intake manifold. The engine control module (ECM) supplies 5 volts to the IAT 2 signal circuit, and a ground for the IAT 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 2 signal circuit. With lower sensor resistance, the ECM detects a lower voltage on the IAT 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.

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 for P0097.

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 for P0098.

DTCs P0097 and P0098 are Type B DTCs.

DTCs P0097 and P0098 are Type B DTCs.

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Electrical Information Reference

DTC Type Definitions

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 readings should be within 15°C (27°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 (-38°F).

⇒	If greater than the specified range, test the signal circuit for a short to ground. If the circuit tests normal, replace the ECM.

4. Install a 3 amp fused jumper wire between the signal circuit and the low reference circuit. 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 terminal A 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 the IAT sensor 2. Refer to Component Testing for instructions.

Compare the IAT sensor 2 resistance to the values listed in the Temperature vs. Resistance table. Refer to Temperature Versus Resistance .

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.