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Home >> Cadillac >> 2018 >> Escalade Base, 4WD >> Repair and Diagnosis >> External Pages >> Different car >> Section 5 (Engine Controls And Fuel - 6.0L (L96) - DTC P0010 To DTC P0341) >> Diagnostic Information And Procedures >> DTC P0096 Or P0111: Intake Air Temperature (IAT) Sensor Performance >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2018 Chevrolet Suburban 3500 HD. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: You must perform the Circuit/System Verification before proceeding with Circuit/System Testing.
  1. Verify none of the conditions listed below exist:
    • A restricted or collapsed air intake duct
    • A misaligned or damaged air intake duct
    • 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.

    • Go to next step: If no condition exists 
  2. Ignition OFF and all systems OFF, it may take up to for 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 2 Ω between the low reference circuit terminal 3 and ground.
    • If 2 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 2 Ω 
  4. Ignition OFF, all vehicle systems OFF, test for less than 2 Ω between the ground circuit terminal 7 and ground.
    • If 2 Ω or greater 
    1. Disconnect the sensor chassis ground.
    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 2 Ω 
  5. 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 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.
      • Go to next step: If infinite resistance
    3. Test for greater than 2 Ω between the ignition voltage circuit terminal 5 and ground.
      • If less than 2 Ω, repair the short to ground on the circuit.
      • If greater than 2 Ω, test all the components connected to the circuit and repair or replace as necessary.
    • Go to next step: If a test lamp illuminates 
  6. Ignition ON.
  7. 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.
      • Go to next step: If infinite resistance
    3. 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 colder than -39°C (-38°F). 
  8. Ignition OFF, install a 3 A fused jumper wire between the signal circuit terminal 1 and the low reference circuit terminal 3, ignition ON.
  9. Verify the scan tool IAT Sensor 1 parameter is warmer than 149°C (300°F).
    • If colder than 149°C (300°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 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
    3. Ignition OFF.
    4. 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 149°C (300°F). 
  10. Test for 4.8 - 5.2 V between the intake air temperature signal 2 circuit terminal 8 and ground.
    • If less than 4.8 V 
    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.
      • Go to next step: If infinite resistance
    3. 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.
    • If greater than 5.2 V 
    1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module, ignition ON.
      NOTE: If the signal circuit is shorted to a voltage the engine control module or the sensor may be damaged.
    2. 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.
      • If less than 1 V, replace the K20 Engine Control Module.
    • Go to next step: If between 4.8 - 5.2 V 
  11. 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.

      • Go to next step: If no DTCs set 
    4. All OK.
    • Go to next step: EL-38522-A, Variable Signal Generator; or equivalent is available 
  12. Ignition OFF, connect the leads of the EL-38522-A  Variable Signal Generator as listed below:
    • Red lead to the signal circuit terminal 8 at the harness connector
    • Black leads to ground
    • Battery voltage supply lead to B+
  13. Set the EL-38522-A  Variable Signal Generator to the specifications listed below:
    • Signal switch to 5 V
    • Duty Cycle switch to 50% (Normal)
    • Frequency switch to 30 Hz
  14. Ignition ON.
  15. 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.

    • Go to next step: If between 28 - 32 Hz 
  16. Test or replace the B75C Multifunction Intake Air Sensor.
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