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Home >> Buick >> 2015 >> Regal GS, AWD >> Repair and Diagnosis >> Engine Performance >> Testing & Diagnosis >> Engine Controls And Fuel - 2.0L (LTG) - DTC P0335 To DTC P2635 And Diagnostic Information And Procedures >> Diagnostic Information and Procedures >> DTC P2199: Intake Air Temperature (IAT) Sensor 1-2 Not Plausible >> Circuit/System Testing

Circuit/System Testing

NOTE:

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

  1. 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.
  2. Test for less than 2 Ω between the low reference circuit terminal 3 and ground.
    • If 2Ω or greater 
    1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module.
    2. Test for less than 2Ω in the low reference circuit end to end.
      • If 2Ω or greater, repair the open or high resistance in the circuit.
      • If less than 2Ω replace the K20 Engine Control Module.
    • If less than 2Ω 
  3. Ignition OFF, all vehicle systems OFF, test for less than 2Ω between the ground circuit terminal 7 and ground.
    • If 2Ω or greater 
    1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module.
    2. Test for less than 2Ω in the ground circuit end to end.
      • If 2Ω or greater, repair the open or high resistance in the circuit.
      • If less than 2Ω, repair the open/high resistance in the ground connection.
    • If less than 2Ω 
  4. Ignition ON, 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 and remove the fuse for the ignition voltage circuit.
    2. Test for less than 2Ω in the ignition voltage circuit end to end.
      • If 2Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2Ω, 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.
    • If a test lamp illuminates 
  5. Ignition ON, test for 4.8-5.2V between the intake air temperature Sensor 1 signal circuit terminal 1 and ground.
    • If less than 4.8V 
    1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module.
    2. Test for infinite resistance between the signal circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance
    3. Test for less than 2Ω in the signal circuit end to end.
      • If 2Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2Ω, replace the K20 Engine Control Module.
    • If greater than 5.2V 
      NOTE:

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

    1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module.
    2. Ignition ON, test for less than 1V between the signal circuit and ground.
      • If 1V or greater, repair the short to voltage on the circuit.
      • If less than 1V, replace the K20 Engine Control Module.
    • If between 4.8-5.2V 
  6. Ignition ON, verify the scan tool IAT Sensor 1 parameter is colder than -39°C (-38°F).
    • If warmer than -39°C (-38°F). 
    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
    3. Test for less than 2Ω in the signal circuit end to end.
      • If 2Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2Ω, replace the K20 Engine Control Module.
    • If colder than -39°C (-38°F). 
  7. Ignition OFF, install a 3 A fused jumper wire between the signal circuit terminal 1 and the low reference circuit terminal 3.
  8. Verify the scan tool IAT Sensor 1 parameter is warmer than 148°C (298°F).
    • If colder than 148°C (298°F). 
    1. Ignition OFF, remove the jumper wire, disconnect the harness connector at the K20 Engine Control Module, ignition ON.
    2. Test for less than 1V between the signal circuit and ground.
      • If 1V or greater, repair the short to voltage on the circuit.
      • If less than 1V
    3. Ignition OFF.
    4. Test for less than 2Ω in the signal circuit end to end.
      • If 2Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2Ω, replace the K20 Engine Control Module.
    • If warmer than 148°C (298°F). 
  9. Ignition ON, test for 4.8-5.2V between the intake air temperature sensor 2 signal circuit terminal 8 and ground.
    • If less than 4.8V 
    1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module.
    2. Test for infinite resistance between the signal circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance
    3. Test for less than 2Ω in the signal circuit end to end.
      • If 2Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2Ω, replace the K20 Engine Control Module.
    • If greater than 5.2V 
      NOTE:

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

    1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module.
    2. Ignition ON, test for less than 1V between the signal circuit and ground.
      • If 1V or greater, repair the short to voltage on the circuit.
      • If less than 1V, replace the K20 Engine Control Module.
    • If between 4.8-5.2V 
  10. Determine if EL-38522-A   Variable Signal Generator or equivalent is available.
    • EL-38522-A, Variable Signal Generator; or equivalent is not available 
    1. Test or replace the B75C Multifunction Intake Air sensor.
    2. 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.
    3. Verify the DTC does not set.
      • If the DTC sets 

        Replace the K20 Engine Control Module.

      • If no DTCs set 
    4. All OK.
    • EL-38522-A, Variable Signal Generator; or equivalent is available 
  11. Ignition OFF, connect the leads of the EL-38522-A   Variable Signal Generator as follows:
    • Red lead to the signal circuit terminal 8 at the harness connector
    • Black leads to ground
    • Battery voltage supply lead to B+
  12. Set the EL-38522-A   Variable Signal Generator to the following specifications.
    • Signal switch to 5V
    • Duty Cycle switch to 50% (Normal)
    • Frequency switch to 30Hz
  13. Ignition ON, verify the scan tool IAT sensor 2 parameter is between 28-32 Hz.
    • If not between 28-32 Hz 

      Replace the K20 Engine Control Module.

    • If between 28-32 Hz 
  14. 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 B111B Turbocharger Boost/Intake Air Temperature sensor.
  15. Test for less than 2 Ω between the intake air temperature sensor 3 low reference circuit terminal 1 and ground.
    • If 2Ω or greater 
    1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module.
    2. Test for less than 2Ω in the low reference circuit end to end.
      • If 2Ω or greater, repair the open or high resistance in the circuit.
      • If less than 2Ω replace the K20 Engine Control Module.
    • If less than 2Ω 
  16. Ignition ON, test for 4.8-5.2V between the signal circuit terminal 2 and ground.
    • If less than 4.8V 
    1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module.
    2. Test for infinite resistance between the signal circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance
    3. Test for less than 2Ω in the signal circuit end to end.
      • If 2Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2Ω, replace the K20 Engine Control Module.
    • If greater than 5.2V 
      NOTE:

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

    1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module.
    2. Ignition ON, test for less than 1V between the signal circuit and ground.
      • If 1V or greater, repair the short to voltage on the circuit.
      • If less than 1V, replace the K20 Engine Control Module.
    • If between 4.8-5.2V 
  17. Test or replace the B75C Multifunction Intake Air Sensor.
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