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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 1987 (Engine Controls And Fuel - 3.6L (LCS) - DTC P0008 To DTC P0193) >> DTC P0101 >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2009 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF, open the hood to disable the Auto-Stop function.
  2. Ignition ON, verify the scan tool hood position parameter displays Open.
    • If the hood position does not display Open, refer to DTC P254F .
  3. Inspect for the following conditions:
    • An engine vacuum leak
    • An air leak in the intake air duct between the mass air flow (MAF) sensor and the throttle body
    • A plugged or collapsed intake air duct
    • Objects that block the MAF sensor air inlet
    • An air filter element that is restricted
    • The hydro-carbon absorber in the air cleaner assembly for ruptures or deterioration.
    • A restricted throttle plate or for carbon build-up around the throttle plate
    • An unseated engine oil dip stick
    • A loose or missing engine oil fill cap
    • An over filled crankcase
    • If you find any of the above conditions, repair as necessary.
  4. Ignition OFF, remove the fuse that supplies B+ to circuit terminal X2-56 of the ECM.
  5. Disconnect the harness connector at the MAF/IAT sensor.
  6. Test for less than 5 Ω between the ground circuit terminal C and ground.
    • If greater than the specified range, test the ground circuit for an open/high resistance.
  7. Install the fuse that supplies B+ to circuit terminal X2-56 of the ECM.
  8. Ignition ON, test for greater 9 V between the ignition voltage circuit terminal B and ground.
    • If less than the specified range, test the ignition voltage circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.
  9. Test for 4.8-5.2 V between the signal circuit terminal A and ground.
    • If less than the specified range, test the signal circuit for an open/high resistance or a short to ground. If the circuit/connections test normal, replace the ECM.
    • If greater than the specified range, test the signal circuit for a short to voltage. If the circuit/connections test normal, replace the ECM.
  10. Ignition OFF, connect the red lead of the J 38522  to the signal circuit terminal A at the MAF/IAT sensor harness connector. Connect the battery voltage supply to B+, and ground the black lead.
  11. Set the J 38522  Signal switch to 5 V, the Frequency switch to 5K, and the Duty Cycle switch to Normal.
  12. Engine Idling, observe the scan tool MAF Sensor frequency parameter. The parameter should be between 4,950-5,025 Hz.
    • If not within the specified range, test the signal circuit for a high resistance. If the circuit/connections test normal, replace the ECM.
  13. If all circuits/connections test normal, replace the MAF sensor.
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