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Home >> GMC >> 2016 >> Canyon SL >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls And Fuel - 2.5L (LCV) - DTC P0010 To DTC P0420 >> Diagnostic Information and Procedures >> DTC P00F4-P00F6: Intake Air Humidity Sensor >> Circuit/System Testing

Circuit/System Testing

  1. Ignition OFF, disconnect the harness connector at the B75C Multifunction Intake Air sensor.
  2. Ignition OFF, all systems OFF. It may take up to for 2 minutes for all vehicle systems to power down. Test for less than 2 Ω between the low reference circuit terminal 3 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 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. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module.
    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.
    • If less than 2 Ω 
  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 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.
      • If infinite resistance, test all components connected to the ignition circuit, replace as necessary.
    • If a test lamp illuminates 
  5. Ignition ON, test for 4.8-5.2 V between the humidity signal 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.
      • 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 
      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 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  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+
  7. Set the EL-38522  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, observe the scan tool Intake Air Humidity parameter. The scan tool parameter should be 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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