P0097
DTC P0097 or P0098
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.
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
Typical Scan Tool Data
Circuit/System Description
The sensors listed below are integrated within the mass air flow/multifunction intake air sensor:
* Intake Air Temperature (IAT) sensor 1
* IAT sensor 2
* Humidity sensor
* Mass Air Flow (MAF) sensor
* Barometric (BARO) pressure sensor
The IAT sensor 2 and the humidity sensor share the same circuit. The IAT sensor 2 signal is displayed by the scan tool as Hertz (Hz) and °C (°F).
The sensors listed below share an ECM supplied 5 V reference circuit:
* IAT sensor 2
* Humidity sensor
* Barometric pressure (BARO) sensor
The sensors listed below share an ECM supplied low reference circuit:
* IAT sensor 1
* IAT sensor 2
* Humidity sensor
* Barometric pressure (BARO) sensor
The table below shows the relationship between temperature and the IAT Sensor 2 signal.
Conditions for Running the DTCs
P0097 and P0098
* The ignition is ON, or the engine is running.
* The Ignition voltage is at least 11 V.
* The DTCs run continuously within the enabling conditions.
Conditions for Setting the DTCs
P0097
Note: The scan tool display range is between -40 and +150°C (-40 and +302°F).
The ECM detects that the IAT sensor 2 signal is less than 10 Hz, colder than -60°C (-76°F), for greater than 5 s.
P0098
The ECM detects that the IAT sensor 2 signal is greater than 390 Hz, warmer than 150°C (302°F), for greater than 5 s.
Action Taken When the DTC Sets
* DTCs P0097 and P0098 are Type B DTCs.
* The ECM commands the cooling fans ON.
Conditions for Clearing the MIL/DTCs
DTCs P0097 and P0098 are Type B DTCs.
Diagnostic Aids
* Inspect the multifunction intake air sensor terminals for corrosion.
* The scan tool IAT Sensor 2 parameter displays the values: 10 Hz; 20°C (68°F) when there is a fault on the signal circuit.
* The Humidity sensor and the IAT sensor 2 signals are sent to the ECM on the same circuit. If the IAT Sensor 2 parameter displays the values: 10 Hz; 20°C (68°F), and there are also Humidity Sensor DTCs, check for a circuit problem.
* With the ignition ON, when the engine is cold and not running, properly functioning IAT sensor 1 and IAT sensor 2 will gradually increase the scan tool IAT Sensor 1 and IAT Sensor 2 parameters. This is due to the heat that is generated by the multifunction intake air sensor heating elements.
Reference Information
Schematic Reference
Engine Controls Schematics [1][2]Electrical Diagrams
Connector End View Reference
Component Connector End Views Fuel Pump and Level Sensor Assembly
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References Control Module References Control Module References for scan tool information
Special Tools
EN 38522 - Variable Signal Generator
For equivalent regional tools, refer to Special Tools Tools and Equipment.
Circuit/System Verification
Note: To minimize the effects of the sensor heating elements, perform Step 1 of this verification procedure only if the ignition has been OFF for 8 hours or more.
1. Ignition ON. Observe the following scan tool parameters. The readings should be within 25°C (45°F) of each other.
* Start-Up IAT Sensor 1
* IAT Sensor 2
* Start-Up ECT
2. Ignition ON, observe the DTC information with a scan tool. Verify that DTC P0651 is not set.
• If the DTC is set, refer to DTC P0641, P0651, P0697, or P06A3 (ECM) Powertrain Management (ECM) for further diagnosis.
3. Engine idling, observe the scan tool IAT Sensor 1 and IAT Sensor 2 parameters. Depending on the current ambient temperature and the vehicle operating conditions, the readings should be between -39 and +149°C (-38 and +300°F).
4. Operate the vehicle within the conditions for running the DTC to verify that the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the freeze frame/failure records data.
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the B75C Multifunction Intake Air Sensor.
2. Ignition OFF, all vehicle systems OFF, this may take up to 2 minutes, test for less than 5 ohms between the low reference circuit terminal 7 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 K20 Engine Control Module.
3. Ignition ON, test for 4.8-5.2 V between the 5 V reference circuit terminal 2 and ground.
• If less than the specified range, test the circuit for an open/high resistance, or short to ground on the 5 V reference circuit. If the circuit tests normal, replace the K20 Engine Control Module.
• If greater than the specified range, test for a short to voltage on the 5 V reference circuit. If the circuit tests normal, replace the K20 Engine Control Module.
4. Test for 4.8-5.2 V between the IAT sensor 2 signal circuit terminal 1 and ground.
• If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 Engine Control Module.
Note: If the signal circuit is shorted to a voltage the ECM or the sensor may be damaged.
• If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the K20 Engine Control Module.
5. Ignition OFF. Connect the leads of the EN 38522 - Variable Signal Generator as follows:
* Red lead to the signal circuit terminal 1 at the harness connector
* Black lead to ground
* Battery voltage supply lead to B+
6. Set the EN 38522 - Variable Signal Generator to the following specifications.
* Signal switch to 5 V
* Duty Cycle switch to 50 % (Normal)
* Frequency switch to 30 Hz
7. Ignition ON. Observe the scan tool IAT Sensor 2 frequency (Hz) parameter. The scan tool parameter should display between 28-32 Hz.
• If the parameter is not within the specified range, replace the K20 Engine Control Module.
8. If all circuits test normal, test or replace the B75C Multifunction Intake Air sensor.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the repair.
* Mass Airflow Sensor Replacement Service and Repair for Mass Air Flow/Multifunction Intake Air sensor replacement.
* Control Module References Control Module References for Engine Control Module replacement, programming, and setup.