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Home >> Chevrolet >> 2015 >> Cruze LT, Automatic Trans >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 11 (Engine Controls And Fuel - 2.0L (LUZ) Diesel - DTC P0016 To DTC P0406) >> Diagnostic Information and Procedures >> DTC P00F4-P00F6: Intake Air Humidity Sensor Circuit >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different variant/trim than selected.
  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.
    NOTE:
    • You must perform Circuit/System Verification  before proceeding with the Circuit/System Testing.
    • You must perform the Diagnostic Repair Verification after completing the Circuit/System Testing.
  2. Test for less than 2 Ω between the low reference circuit terminal 7 and ground.
    • If 2 Ω or greater 
    1. Ignition OFF, 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.
    • If less than 2 Ω 
  3. Ignition ON.
  4. Test for 4.8-5.2 V between the 5 V reference circuit terminal 2 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 5 V reference circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance
    3. Test for less than 2 Ω in the 5 V reference 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.
    2. Ignition ON, test for less than 1 V between the 5 V reference 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.
    • If between 4.8-5.2 V 
  5. Ignition ON. Test for 4.8-5.2 V between the IAT 2 signal circuit terminal 1 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.
      • 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.
      NOTE: If the signal circuit is shorted to a voltage the engine control module or the sensor may be damaged.
    2. Ignition ON, 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.
    • If between 4.8-5.2 V 
  6. Ignition OFF, connect the leads of the EL-38522-A  Variable Signal Generator as follows:
    • Red lead to the signal circuit terminal 1 at the harness connector
    • Black leads to ground
    • Battery voltage supply lead to B+
  7. Set the EL-38522-A  Variable Signal Generator to the following specifications.
    • Signal switch to 5 V
    • Frequency switch to 250 Hz
    • Duty Cycle switch to 50% (Normal)
  8. Ignition ON, verify the scan tool Intake Air Humidity parameter is between 45-55%.
    • If not between 45-55%. 

      Replace the K20 Engine Control Module.

    • If between 45-55%. 
  9. Test or replace the B75C Multifunction Intake Air Sensor.
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