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P2199




DTC P2199

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.

DTC Descriptor
DTC P2199
- Intake Air Temperature (IAT) Sensor 1-2 Correlation

Diagnostic Fault Information





Typical Scan Tool Data










Circuit/System Description

The intake air temperature (IAT) sensor is integrated with the mass air flow (MAF) sensor. The IAT sensor is a variable resistor that measures the temperature of the air when it first enters the induction system. This sensor is also used to calculate ambient air temperature. The engine control module (ECM) supplies 5 volts to the IAT sensor signal circuit and a ground for the low reference circuit.

The intake air temperature (IAT) sensor 2 is integrated with the intake air pressure and temperature sensor. The IAT sensor 2 is a variable resistor that measures the temperature of the air after the turbocharger and the charge air cooler, and before it enters the engine intake manifold. The engine control module (ECM) supplies 5 volts to the IAT sensor 2 signal circuit and a ground for the low reference circuit.

The purpose of this diagnostic is to analyze the performance of the 2 sensors by comparing them to each other under various operating conditions to determine if they are within an acceptable temperature range of each other.

Conditions for Running the DTC

* The engine is running.
* The MAF is between 9-50 g/s.
* The vehicle speed is greater than 71 km/h (44 mph).
* The boost pressure to barometric (BARO) pressure ratio is less than 1.4.
* The above conditions must be met for greater than 20 seconds.
* This DTC runs continuously within the enabling conditions.

Conditions for Setting the DTC

The ECM detects that the difference in range between the IAT and the IAT sensor 2 either plus or minus is greater than 20°C (36°F) for greater than 4 seconds continuously or 50 seconds cumulative.

Action Taken When the DTC Sets

DTC P2199 is a Type B DTC.

Conditions for Clearing the MIL/DTC

DTC P2199 is a Type B DTC.

Diagnostic Aids

* When the engine is cold, at ignition ON, a properly functioning IAT sensor will gradually increase the scan tool IAT Sensor parameter. This is due to the heat that is generated by the MAF sensor heating elements.
* Depending on the ambient temperature, an IAT sensor signal circuit that is shorted to the MAF sensor signal circuit can cause either a rapid fluctuation in the IAT Sensor parameter or cause it to become stuck at a given value.
* An IAT low reference circuit that is open can cause the IAT Sensor parameter response to be sluggish.
* An IAT sensor 2 signal circuit that is shorted to the intake air pressure signal circuit can cause the IAT Sensor 2 parameter response to be sluggish or become stuck at a given value.

Reference Information
Schematic Reference

Engine Controls Schematics (Electrical Diagrams)
Connector End View Reference

Component Connector End Views (Connector Views)
Electrical Information Reference

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions (Diagnostic Trouble Code Descriptions)
Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information.

Circuit/System Verification

1. If the ignition has been OFF for 8 hours or greater, the IAT sensor, the IAT sensor 2 and the engine coolant temperature (ECT) sensor should be within 9°C (16°F) of each other. Ignition ON, observe the scan tool IAT Sensor, IAT Sensor 2 and the ECT Sensor parameters. Compare those sensor parameters to each other to determine if the condition is current.
2. Engine running, observe the scan tool IAT Sensor parameter. The reading should be between -39 to +120°C (-38 to +248°F) depending on the current ambient temperature and the vehicle operating conditions.
3. Engine running, observe the scan tool IAT Sensor 2 parameter. The reading should be between -39 to +130°C (-38 to +266°F) depending on the current ambient temperature and the vehicle operating conditions.
4. Operate the vehicle within the Conditions for Running the DTC to verify 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. Verify that the induction system components are properly positioned and connected.
2. Ignition OFF, disconnect the harness connector at the MAF/IAT sensor.
3. Ignition OFF for 90 seconds, test for less than 5 ohms between the MAF sensor ground circuit terminal B and ground.

• If greater than the specified range, test the MAF sensor ground circuit for an open/high resistance.

4. Test for less than 5 ohms between the IAT low reference circuit terminal D 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.

5. Disconnect the harness connector at the intake air pressure and temperature sensor.
6. Test for less than 5 ohms between the low reference circuit terminal 1 or A 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.

7. Disconnect the ECM.
8. Test for less than 5 ohms between the IAT sensor signal circuit terminal E and the ECM connector X2, terminal 50.

• If greater than the specified range, test the IAT sensor signal circuit for an open/high resistance.

9. Test for less than 5 ohms between the IAT sensor 2 signal circuit terminal 2 or B and the ECM connector X1, terminal 86.

• If greater than the specified range, test the IAT sensor 2 signal circuit for an open/high resistance.

10. If the circuits test normal, test both the IAT sensor and the IAT sensor 2.

Component Testing

Measure and record the resistance of the IAT sensor and the IAT sensor 2 at various ambient temperatures, then compare those measurements to the Temperature vs Resistance table. Refer to Temperature Versus Resistance (ECT) (Temperature Versus Resistance (ECT))Temperature Versus Resistance (IAT 1) (Temperature Versus Resistance (IAT 1))Temperature Versus Resistance (IAT 2) (Temperature Versus Resistance (IAT 2)).

Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Mass Airflow Sensor Replacement (Service and Repair)
* Intake Air Pressure and Temperature Sensor Replacement (Service and Repair)
* Control Module References (Programming and Relearning) for ECM replacement, setup, and programming

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