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Home >> Buick >> 2015 >> Regal GS, AWD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 15 (Engine Controls And Fuel - 2.4L - DTC P0114 To DTC P0604) >> Diagnostic Information and Procedures >> DTC P0112, P0113, or P0114: Intake Air Temperature (IAT) Sensor (LEA) >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different variant/trim than selected.
  1. Ignition OFF, disconnect the harness connector at the B75B Mass Air Flow/Intake Air Temperature sensor.
  2. 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 
  3. Ignition ON, test for 4.8-5.2V between the intake air temperature Sensor 1 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 
  4. 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). 
  5. Ignition OFF, install a 3A fused jumper wire between the signal circuit terminal E and the low reference circuit terminal D.
  6. 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). 
  7. Test or replace the B75B Mass Air Flow/Intake Air Temperature sensor.
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