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P2199



DTC P2199

DTC DESCRIPTOR

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

DIAGNOSTIC FAULT INFORMATION




IAT Temperature Sensor:






IMPORTANT: Always perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.


TYPICAL SCAN TOOL DATA

IAT 2 Temperature Sensor:




IAT Sensor:






CIRCUIT/SYSTEM DESCRIPTION
The intake air temperature (IAT) sensor 2 is a variable resistor. The IAT 2 sensor measures the temperature of the air at the engine 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 2 sensor 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 monitors the IAT 2 and the IAT signal voltages for a signal voltage that is not within a calibrated range of each other.

CONDITIONS FOR RUNNING THE DTC
- DTCs P0097, P0098, P0112, P0113, P0117, P0118 are not set.
- The engine has been OFF for more than 10 hours.
- The IAT sensor is more than 10°C (50°F).
- DTC P2199 runs continuously within the enabling conditions

CONDITIONS FOR SETTING THE DTC
At start-up, after a 10 hour engine soak time, the IAT 2 sensor temperature is more than 5.3°C (9°F) higher or lower than the IAT Sensor.

ACTION TAKEN WHEN THE DTC SETS
- The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
- The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

CONDITIONS FOR CLEARING THE MIL/DTC
- The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
- A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
- A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
- Clear the MIL and the DTC with a scan tool.

CIRCUIT/SYSTEM VERIFICATION

IMPORTANT: If you cannot duplicate the condition, 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.

1. If DTC P0112, P0113, P0097, or P0098 are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle.
2. If the ignition has been OFF for more than 10 hours, the ECT, IAT, and IAT 2, should be within 6°C (11°F) of each other and also the ambient temperature. Turn ON the ignition, with the engine OFF, use a scan tool to observe the IAT 2 and the ECT sensor parameters. Compare all those sensor parameters to each other and also to the ambient temperature. A slight to moderate resistance in either signal or low reference circuit, can widen the spread between the 2 IAT sensors, and cause this DTC to set.
3. An IAT sensor that is skewed lower at various ambient temperatures, due to more resistance than is normal, can widen the spread between the two sensors and cause this DTC to set. Measure and record the resistance of the IAT and IAT 2 sensors at various ambient temperatures, and then compare those measurements to the Temperature vs. Resistance Table.
4. Inspect both IAT sensors terminals, for corrosion or a poor connection.
5. If the ignition has been OFF for more than 10 hours, then determine which IAT sensor is skewed by comparing ECT, IAT, and IAT 2 sensor parameters with a scan tool.

CIRCUIT/SYSTEM TESTING
1. With the ignition OFF, disconnect the IAT 2 and ECM connectors, with a DMM, measure for a resistance of less than 10 ohms on the signal and low reference circuits between IAT 2 and the ECM.
- If the resistance is more than 10 ohms, repair the circuit with the high resistance.
2. With the ignition OFF, disconnect the IAT and ECM connectors, with a DMM, measure for a resistance of less than 10 ohms on the signal and low reference circuits between the IAT and ECM.
- If the resistance is more than 10 ohms, repair the circuit with the high resistance.
3. Remove and test the IAT 2 and IAT sensors.
- If all circuits and sensors test OK, replace the ECM.

COMPONENT TESTING
1. Compare the resistance of the IAT 2 sensor to the temperature vs resistance table.
- If the difference is more than 9 percent, replace the IAT 2 sensor.
2. Compare the resistance of the IAT sensor to the temperature vs resistance.
- If the difference is more than 9 percent, replace the IAT sensor.

REPAIR INSTRUCTIONS

IMPORTANT: Always perform the Diagnostic Repair Verification after completing the diagnostic procedure.
- Intake Air Temperature (IAT) Sensor 2 Replacement
- Mass Air Flow (MAF)/Intake Air Temperature (IAT) Sensor Replacement
- Control Module References for EC replacement, setup, and programming
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