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Home >> Buick >> 2015 >> Regal GS, AWD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 14 (Engine Controls And Fuel - 2.4L - DTC P0010 To DTC P0114 (LUK)) >> Diagnostic Information and Procedures >> DTC P0111: Intake Air Temperature (IAT) Sensor (LUK) >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different variant/trim than selected.
NOTE:

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

  1. Verify none of the following conditions exist:
    • A restricted, collapsed, misaligned, or damaged air intake duct
    • An intake manifold leak
    • A MAP sensor seal that is leaking, missing, or damaged
    • Any water intrusion in the induction system
    • An Intake Manifold Resonator with a leaking seal, or a cracked or broken housing
    • If a condition exists 

      Repair or replace component as appropriate.

    • If no condition exists 
  2. Ignition OFF, disconnect the harness connector at the B75B Mass Air Flow/Intake Air Temperature sensor.
  3. Ignition OFF, and all systems OFF, it may take up to for 2 minutes for all vehicle systems to power down. Test for less than 2Ω between the low reference circuit terminal D 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 
  4. Ignition OFF, all vehicle systems OFF, test for less than 2Ω between the ground circuit terminal B and ground.
    • If 2Ω or greater 
    1. Ignition OFF. Disconnect the sensor chassis ground.
    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 
  5. Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal C 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 
  6. Ignition ON, test for 4.8-5.2V between the intake air temperature signal circuit terminal E 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 
  7. Ignition ON, verify the scan tool IAT Sensor 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 E 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). 
  8. Ignition OFF, install a 3 A fused jumper wire between the signal circuit terminal E and the low reference circuit terminal D.
  9. Verify the scan tool IAT Sensor 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). 
  10. Test or replace the B75B Mass Air Flow/Intake Air Temperature sensor.
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