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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 P0101 >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2010 GMC Sierra, 2010 GMC Cab & Chassis Sierra, 2010 Chevrolet Silverado, and 2010 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
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 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 low reference circuit terminal 4 and ground.
    • If greater than the specified range, test the IAT sensor 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 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. Ignition OFF, connect the harness connector at the MAF/IAT sensor.
  8. Engine idling at operating temperature, perform the following:
    1. Command the EGR solenoid to 0 percent with a scan tool.
    2. Observe the Airflow Leak Equivalence Ratio parameter for 10 s. The value should be between 0.87:1 and 1.15:1.
    3. Observe the Airflow Leak Equivalence Ratio parameter while slowly increasing the engine speed until reaching wide open throttle (WOT). After 10 s, the value should stabilize and be between 0.87:1 and 1.15:1.
  9. Remove the Intake Manifold Tube. Refer to Intake Manifold Tube Replacement .
  10. 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 and gaskets.
  11. Ignition OFF, disconnect the harness connector at the MAF/IAT sensor.
  12. 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.
  13. Set the J 38522  signal switch to 5 V, the frequency to 5K, and the Duty Cycle to Normal.
  14. Engine idling, 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.
  15. If all circuits test normal, test or replace the MAF/IAT sensor.
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