Buick Regal: DTC P2199

Diagnostic Instructions

• Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
• Review Strategy Based Diagnosis for an overview of the diagnostic approach.
• Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

DTC P2199

Intake Air Temperature (IAT) Sensor 1-2 Not Plausible

Diagnostic Fault Information

IAT Sensor 1

IAT Sensor 2 and Intake Air Humidity

Typical Scan Tool Data

IAT Sensor 1

IAT Sensor 2 and Intake Air Humidity

Circuit/System Description

The intake air temperature (IAT) sensor 1 is a variable resistor that measures the temperature of the air in the sensor bore. The engine control module (ECM) supplies 5 V to the IAT sensor 1 signal circuit and a ground for the IAT sensor 1 low reference circuit. The signal varies with inlet air temperature and is displayed by the scan tool as ºC (ºF).

The IAT sensor 2 produces a frequency signal, based on the inlet air temperature, which is equal to the humidity present within the sensor bore. The signal varies with inlet air temperature and is displayed by the scan tool as ºC (ºF) and Hertz (Hz) and the relative humidity is displayed in percent (%).

The ECM supplies a regulated voltage to the signal circuit. The signal circuit is shared by the IAT sensor 2 and the humidity sensor. Ignition voltage and ground circuits are also supplied to the multifunction intake air sensor's internal circuits for these sensors:

• IAT sensor 2
• Humidity sensor
• MAF sensor

The multifunction intake air sensor houses the following:

• IAT sensor 1
• IAT sensor 2
• Humidity sensor
• MAF sensor
• BARO pressure sensor

IAT Sensor 1 - Temperature, Resistance, Voltage Table

IAT Sensor 2 - Temperature, Frequency Table

Conditions for Running the DTC

• The ignition is ON.
• Ignition 1 voltage is at least 11 V.
• This DTC runs continuously within the enabling conditions.

Conditions for Setting the DTC

The ECM detects that the absolute difference between the IAT sensor 1 and the IAT sensor 2 temperatures is greater than 55ºC (99ºF) for longer than 5 s.

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

• With the ignition ON, the engine OFF, if the engine is cold, a properly functioning IAT sensor 2 will gradually increase the scan tool IAT Sensor 2 parameter. This is due to the heat that is generated by the multifunction intake air sensor heating elements.
• 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; -40ºC (-40ºF), and there are Humidity Sensor DTCs, check for a circuit problem.

Reference Information

Schematic Reference

Engine Controls Wiring Schematics (LTG)

Connector End View Reference

Component Connector End View Index

Electrical Information Reference

• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs

Powertrain Component Views

Powertrain Component Views

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Special Tools

EL-38522-A Variable Signal Generator

For equivalent regional tools, refer to Special Tools (Diagnostic Tools) and Special Tools (Mechanical Tools).

Circuit/System Verification

1. Ignition On.

2. Verify that DTC P0097, P0098, P0099, P00F4, P00F5, P00F6, P0102, P0103, P0112, P0113, P0114, P0641, P0651, P0697, P06A3 or P06D2 is not set.

• If any of the DTCs are set

Refer to Diagnostic Trouble Code (DTC) List - Vehicle for further diagnosis.

• Go to next step: If none of the DTCs are set

3. Ignition ON.

4. Verify the following scan tool parameters are within 30ºC (54ºF) of each other.

• Start-Up IAT Sensor 1
• IAT Sensor 2
• If not within 30ºC (54ºF)

Refer to Circuit/System Testing.

• Go to next step: If within 30ºC (54ºF)

5. Engine running, verify the following scan tool parameters are between: -38 and +149ºC (-36 and +300ºF).

• IAT Sensor 1
• IAT Sensor 2
• If not between: -38 and +149ºC (-36 and +300ºF)

Refer to Circuit/System Testing.

• Go to next step: If between: -38 and +149ºC (-36 and +300ºF)

6. 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 data.

7. Verify the DTC does not set.

• If the DTC sets

Refer to Circuit/System Testing.

• Go to next step: If the DTC does not set

8. All OK

Circuit/System Testing

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

1. Check the integrity of the entire air induction system and verify that none of the following conditions exist:

• A restricted or collapsed air intake duct
• An intake manifold leak
• A misaligned or damaged air intake duct
• Any water intrusion in the induction system
• If a condition exists

Repair or replace component as appropriate.

• Go to next step: If no condition exists

2. Ignition Off, and all vehicle systems Off, it may take up to 2 min. for all vehicle systems to power down. Disconnect the harness connector at the B75C Multifunction Intake Air sensor.

3. Test for less than 5 Ω between the low reference circuit terminal 3 and ground.

• If 5 Ω or greater

1. Disconnect the harness connector at the K20 Engine Control Module.
2. Test for less than 2 Ω in the low reference circuit end to end.
   • If 2 Ω or greater, repair the open or high resistance in the circuit.
   • If less than 2 Ω replace the K20 Engine Control Module.

• Go to next step: If less than 5 Ω

Test for less than 5 Ω between the ground circuit terminal 7 and ground.

• If 5 Ω or greater

1. Ignition Off.
2. Test for less than 2 Ω in the ground circuit end to end.
   • If 2 Ω or greater, repair the open or high resistance in the circuit.
   • If less than 2 Ω, repair the open/high resistance in the ground connection.

• Go to next step: If less than 5 Ω

5. Ignition On.

6. Verify that a test lamp illuminates between the ignition circuit terminal 5 and ground.

• If the test lamp does not illuminate and the circuit fuse is good

1. Ignition Off, remove the test lamp, the fuse for the ignition voltage circuit, and disconnect all components on the circuit.
2. Test for less than 2 Ω in the ignition voltage circuit end to end.
   • If 2 Ω or greater, repair the open/high resistance in the circuit.
   • If less than 2 Ω, verify the fuse is not open and there is voltage at the fuse.

• If the test lamp does not illuminate and the circuit fuse is open

1. Ignition Off, remove the test lamp and remove the fuse for the ignition voltage circuit.
2. Test for infinite resistance between the ignition voltage circuit and ground.
   • If less than infinite resistance, repair the short to ground on the circuit.
   • If infinite resistance, test all components connected to the ignition circuit, replace as necessary.

• Go to next step: If a test lamp illuminates

7. Verify the scan tool Intake Air Temperature Sensor 1 parameter is colder than -39ºC (-38ºF).

• If warmer than -39ºC (-38ºF).

1. Ignition Off, disconnect the harness connector at the K20 Engine Control Module.
2. Test for infinite resistance between the signal circuit terminal 1 and ground.
   • If less than infinite resistance, repair the short to ground on the circuit.
   • If infinite resistance, replace the K20 Engine Control Module.

• Go to next step: If colder than -39ºC (-38ºF).

8. Ignition Off, install a 3 A fused jumper wire between the IAT 1 signal circuit terminal 1 and the low reference circuit terminal 3.

9. Ignition On.

10. Verify the scan tool Intake Air Temperature Sensor 1 parameter is warmer than 148ºC (298ºF).

• If colder than 148ºC (298ºF).

1. Ignition Off, remove the jumper wire, disconnect the harness connector at the K20 Engine Control Module.
2. Ignition On.
3. Test for less than 1 V between the signal circuit and ground.
   • If 1 V or greater, repair the short to voltage on the circuit.
   • Go to next step: If less than 1 V
4. Ignition Off.
5. Test for less than 2 Ω in the signal circuit end to end.
   • If 2 Ω or greater, repair the open/high resistance in the circuit.
   • If less than 2 Ω, replace the K20 Engine Control Module.

• Go to next step: If warmer than 148ºC (298ºF).

11. Ignition On.

NOTE: The intake air temperature sensor 2 signal circuit is pulled up with low current voltage within the controller. Normally, a voltage near B+ can be measured on the circuit with a DMM, but the current will not be high enough to illuminate a test lamp.

12. Verify the scan tool Intake Air Humidity Sensor parameter is less than 1%.

• If 1% or greater

1. Ignition Off, disconnect the harness connector at the K20 Engine Control Module.
2. Test for infinite resistance between the IAT 2 signal circuit terminal 8 and ground.
   • If less than infinite resistance, repair the short to ground on the circuit.
   • If infinite resistance, replace the K20 Engine Control Module.

• Go to next step: If less than 1%

13. Ignition Off, install a 3 A fused jumper wire between the IAT 2 signal circuit terminal 8 and the low reference circuit terminal 3.

14. Ignition On.

15. Verify the scan tool Intake Air Humidity Sensor parameter is greater than 99%.

• If 99% or less

NOTE: If the signal circuit is shorted to a voltage the engine control module or the sensor may be damaged.

1. Ignition Off, remove the jumper wire and disconnect the harness connector at the K20 Engine Control Module.
2. Ignition On.
3. Test for less than 1 V between the IAT 2 signal circuit terminal 8 and ground.
   • If 1 V or greater, repair the short to voltage on the circuit.
   • Go to next step: If less than 1 V.
4. Ignition Off.
5. Test for less than 2 Ω in the signal circuit end to end.
   • If 2 Ω or greater, repair the open/high resistance in the circuit.
   • If less than 2 Ω, replace the K20 Engine Control Module.

• Go to next step: If greater than 99%

16. Test or replace the B75C Multifunction Intake Air sensor.

Component Testing

Multifunction Intake Air Sensor

1. Ignition Off, disconnect the harness connector at the B75C Multifunction Intake Air Sensor.

2. Connect a DMM between the IAT sensor 1 signal terminal 1 and the low reference terminal 3

NOTE: A thermometer can be used to test the sensor off the vehicle.

3. Test the IAT sensor 1 by varying the sensor temperature while monitoring the sensor resistance.

Compare the readings with the Temperature Versus Resistance - Intake Air Temperature Sensor table for Hitachi Sensors. The resistance values should be in range of the table values.

• If not within the specified range

Replace the B75C Multifunction Intake Air Sensor.

• Go to next step: If within the specified range

4. All OK.

Multifunction Intake Air Sensor

1. Test the IAT Sensor 2 by varying the sensor temperature while monitoring the air temperature with a thermometer. Compare the readings with the scan tool IAT Sensor 2 parameter. The values should be within 5%.

• If not within the specified range

Replace the B75C Multifunction Intake Air Sensor.

• Go to next step: If within the specified range

2. All OK.

Testing with EL-38522-A

NOTE: In-correct diagnosis will result if Circuit/System Testing is not completed before performing the following test.

1. Perform the following test using a EL-38522-A Variable Signal Generator or equivalent, if available.

2. Ignition Off, connect the leads of the EL-38522-A Variable Signal Generator as follows:

1. Red lead to the signal circuit terminal 8 at the harness connector
2. Black leads to ground
3. Battery voltage supply lead to B+

3. Set the EL-38522-A Variable Signal Generator to the following specifications.

• Signal switch to 5 V
• Duty Cycle switch to 50 % (Normal)
• Frequency switch to 250 Hz

4. Ignition On.

5. Verify the scan tool IAT Sensor 2 parameters listed below are within the ranges listed below:

• IAT Sensor 2 is between 248 - 252 Hz

NOTE: Changing the frequency should cause a warmer or colder IAT 2 temperature.

• IAT Sensor 2 is between 70 - 76ºC (160 - 166ºF)

NOTE: Increasing or decreasing the duty cycle should have an inverse affect on humidity.

• Intake Air Humidity Sensor is between 48 - 52%
• If a parameter is not within the specified range

Replace the K20 Engine Control Module.

• Go to next step: If all the parameters are within the specified range

6. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

• Mass Airflow Sensor with Intake Air Temperature Sensor Replacement for multifunction intake air sensor replacement
• Control Module References for engine control module replacement, programming, and setup.

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