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Home >> GMC >> 2006 >> Sierra 1500 HD, RWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 1657 (Engine Control System & Fuel System - 6.6L (LMM) - DTC P0016 To DTC P02E7) >> DTC P0102 or P0103 >> Circuit/System Testing

Circuit/System Testing

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IMPORTANT:
  • You must perform the Circuit/System Verification before proceeding with the circuit/system testing.
  • You must perform the Repair Verification after completing the Circuit/System Testing.
  1. Inspect for the following conditions:
    • A dirty or deteriorating air filter element
    • A leaking, loose, or cracked PCV pipe or seal
    • A loose or disconnected charge air cooler hose or pipe
    • A restricted or collapsed air intake duct
    • A misaligned or damaged air intake duct
    • Any objects blocking the air inlet probe of the MAF/IAT sensor
    • Any contamination or debris on the sensing elements in the probe of the MAF/IAT sensor
    • A cracked or damaged MAF sensor housing
    • Any water intrusion in the induction system
    • Any snow or ice build-up at the air cleaner, MAF or MAP sensors in cold climates
    • An intake manifold leak
    • A MAP sensor seal that is leaking, missing, or damaged
    • An Intake Manifold Resonator with a leaking seal, or a cracked or broken housing
    • If you find any of the above conditions, repair as necessary.
  2. Ignition OFF, disconnect the harness connector at the MAF/IAT sensor.
  3. Ignition OFF and all vehicle systems OFF. It may take up to 2 minutes for all vehicle systems to power down. Test for less than 5 Ω between the MAF low reference circuit terminal 2 and ground.
    • If greater than the specified range, test the MAF low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
  4. Ignition OFF and all vehicle systems OFF. It may take up to 2 minutes for all vehicle systems to power down. Test for less than 5 Ω between the IAT sensor 1 low reference circuit terminal 4 and ground.
    • If greater than the specified range, test the IAT sensor 1 low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
  5. Ignition ON, verify that a test lamp illuminates between the ignition voltage circuit terminal 3 and ground.
    • If the test lamp does not illuminate, test the ignition voltage circuit for a short to ground or an open/high resistance.
  6. Ignition ON, test for 4.8-5.2 V between the MAF signal circuit terminal 1 and ground.
    • If less than the specified range, test the MAF signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.
    • If greater than the specified range, test the MAF signal circuit for a short to voltage. If the circuit tests normal, replace the ECM.
  7. Remove the intake manifold tube. Refer to Intake Manifold Tube Replacement .
  8. Visually inspect the EGR valve and verify the valve is in the closed position.
    • If the EGR valve is not in the closed position, replace the EGR valve.
  9. Ignition OFF, disconnect the harness connector at the MAF/IAT sensor.
  10. Ignition OFF, connect the red lead of the J 38522  to the MAF signal circuit terminal 1 at the MAF/IAT sensor harness connector. Connect the battery voltage supply to B+. Connect the black lead to ground.
  11. Set the J 38522  signal switch to 5 V, the frequency to 5K, and the Duty Cycle to Normal.
  12. Ignition ON, engine OFF,, observe the scan tool MAF sensor parameter. The scan tool MAF Sensor parameter should be between 4,950-5,050 Hz.
    • If the MAF Sensor parameter is not within the specified range, replace the ECM.
  13. If all circuits and the EGR valve test normal, replace the MAF/IAT sensor.
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