Diagnostic Instructions

DTC Descriptors

DTC P0097: Intake Air Temperature (IAT) Sensor 2 Circuit Low Voltage

DTC P0098: Intake Air Temperature (IAT) Sensor 2 Circuit High Voltage

Diagnostic Fault Information

Circuit	Short to Ground	High Resistance	Open	Short to Voltage
IAT Sensor 2 Signal	P0097	P0098	P0098	P0098
IAT Sensor 2 Low Reference	--	P0098	P0098	P0098

Typical Scan Tool Data

IAT Sensor 2

Circuit	Short to Ground	Open	Short to Voltage
Operating Conditions: Ignition ON or Engine Running Parameter Normal Range: -39 to +190°C (-38 to +374°F)
IAT Sensor 2 Signal	200°C (392°F)	-40°C (-40°F)	-40°C (-40°F)
IAT Sensor 2 Low Reference	--	-40°C (-40°F)	-40°C (-40°F)

Circuit/System Description

The intake air temperature (IAT) sensor 2 is a variable resistor. The IAT sensor 2 measures the temperature of the air entering the engine. The engine control module (ECM) supplies 5 volts to the IAT signal 2 circuit, and a ground for the IAT sensor 2 low reference circuit. When the IAT sensor is cold, the sensor resistance is high. When the air temperature increases, the sensor resistance decreases. With high sensor resistance, the ECM detects a high voltage on the IAT signal circuit. With lower sensor resistance, the ECM detects a lower voltage on the IAT signal circuit.

Conditions for Running the DTC

P0097

P0098

Conditions for Setting the DTC

P0097

The ECM detects that the IAT sensor 2 signal voltage is less than 0.1 volt.

P0098

The ECM detects that the IAT sensor 2 signal voltage is more than 4.9 volts.

Action Taken When the DTC Sets

DTCs P0097 and P0098 are Type A DTCs.

Conditions for Clearing the DTC

DTCs P0097 and P0098 are Type A DTCs.

Diagnostic Aids

Inspect for any recent engine mechanical repairs. An incorrectly installed IAT sensor 2 will cause this DTC to set.

Reference Information

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Engine Control Module Connector End Views

Electrical Information Reference

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Circuit/System Verification

Verify the integrity of the IAT sensor by inspecting for the following conditions:

Circuit/System Testing

Important: You must perform Circuit/System Verification before proceeding with Circuit/System Testing.

1. Ignition OFF, disconnect the harness connector at the IAT sensor 2.
2. Ignition OFF, test for less than 5 ohms between the low reference circuit terminal 1 and ground.

⇒	If greater than the specified value, 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 value, test the signal circuit terminal 2 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 190°C (374°F).

⇒	If less than the specified range, test the signal circuit and low reference 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, replace the IAT sensor 2.

Component Testing

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

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.