Description
The DTC P2199 Intake Air Temperature (IAT) Sensor 1/2 Correlation diagnostic compares the IAT sensor 1 input with the IAT sensor 2 input. There are 2 IAT sensors on the 3.5L engine. IAT sensor 1 is located in the intake air duct and IAT sensor 2 is located in the intake manifold. The IAT sensor is a thermistor. A thermistor is a resistor whose value varies with temperature. The IAT sensors resistance is high when the coolant temperature is cold, and the IAT sensors resistance is low when the coolant temperature is warm. The IAT sensor is wired in series with a fixed resistor in the powertrain control module (PCM). The PCM applies 5 volts to the IAT sensor. The PCM monitors the voltage across the IAT sensor and converts the voltage into a temperature reading. The PCM expects the output of the 2 IAT sensors to follow the same linear path. If the 2 sensors report conflicting information to the PCM, a DTC P2199 can set.
The following table illustrates the difference between temperature, resistance, and voltage:
IAT | IAT Resistance | IAT Signal Voltage |
|---|---|---|
Cold | High | High |
Warm | Low | Low |
DTC Descriptor
This diagnostic procedure supports the following DTC:
P2199 Intake Air temperature (IAT) Sensor 1/2 Correlation.
Conditions for Running the DTC
| • | DTCs P0097, P0098, and P2610 are not set. |
| • | The ignition is ON. |
| • | The engine has been OFF for at least 8 hours. |
| • | DTC P2199 runs continuously once the above conditions are met. |
Conditions for Setting the DTC
| • | The temperature difference between IAT sensor 1 and IAT sensor 2 is 25°C (77°F) or more. |
| • | The above condition is present for at least 7 seconds. |
Action Taken When the DTC Sets
| • | The PCM illuminates the malfunction indicator lamp (MIL) after 2 consecutive ignition cycles in which the diagnostic fails. |
| • | The PCM records the operating conditions at the time the diagnostic fails. This information is stored in the Freeze Frame buffer. |
Conditions for Clearing the MIL/DTC
| • | The PCM turns OFF the MIL after 3 consecutive trips without a fault. |
| • | The PCM clears a History DTC after 40 consecutive warm-up cycles without a fault. |
| • | Use the scan tool Clear DTC Information function. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This step determines if a condition is present.
-
After replacing the PCM, a new minimum throttle position and idle speed must also be established.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics Connector End View Reference: Powertrain Control Module Connector End Views or Engine Controls Connector End Views | ||||
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | |
Important: The intake air temperature (IAT) sensors should be cooled to ambient temperature. Does the scan tool indicate that the IAT sensor 1 and IAT sensor 2 are within the specified value of each other? | 5°C (9°F) | Go to Step 3 | Go to Step 4 | |
3 |
Does the DTC fail this ignition cycle? | -- | Go to Step 4 | Go to Intermittent Conditions |
4 |
Did you locate an out of range sensor? | -- | Go to Step 6 | Go to Step 5 |
5 | Test the IAT sensor circuits for high resistance. Refer to Circuit Testing . Did you find and correct the condition? | -- | Go to Step 8 | Go to Step 7 |
6 | Replace the IAT sensor. Refer to Intake Air Temperature Sensor 1 Replacement or Intake Air Temperature Sensor 2 Replacement . Did you complete the replacement? | -- | Go to Step 8 | -- |
Did you complete the replacement? | -- | Go to Step 8 | -- | |
8 |
Does the DTC run and pass? | -- | Go to Step 9 | Go to Step 2 |
9 | With a scan tool, select Capture Info in order to observe the stored information. Does the scan tool display any DTCs that you have not diagnosed? | -- | System OK | |
