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Home › Buick › 2008 › Allure CXS › Repair and Diagnosis › Engine Performance › System › Engine Control System & Fuel System - 3.6L - DTC P0008 To DTC P0333 › DTC P0101 › Circuit/System Testing

Circuit/System Testing

  1. 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.
  2. Ignition OFF, disconnect the harness connector at the MAF/IAT sensor.
  3. Remove the fuse that supplies B+ to circuit terminal X2-36 of the engine control module (ECM).
  4. Test for less than 5 ohms of resistance between the low reference circuit terminal 3 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.
  5. Install the fuse that supplies B+ to circuit terminal X2-36 of the ECM.
    6. NOTE: Do NOT use the low reference circuit in the component harness connector for this test. Damage to the control module may occur due to excessive current draw.
  6. Ignition ON, load test for B+ between the ignition voltage circuit terminal 2 and ground.
    • If less than the specified range, repair the ignition voltage circuit for an open/high resistance.
    7. IMPORTANT: The engine control module (ECM) for this engine is not equipped with 5-volt reference DTCs. The 5-volt reference circuits are internally and externally connected at the controller. Other sensors that share the 5-volt reference circuit may also have DTCs set. Disconnecting a sensor on the shared 5-volt reference circuit may isolate a shorted sensor. Review the electrical schematic and diagnose the shared circuits and sensors.
  7. Test for 4.8-5.2 volts between the 5 volt reference circuit terminal 4 and the low reference circuit terminal 3.
    • If less than the specified range, test the 5 volt reference circuit for an open or for a short to ground. If the circuit/connections test normal, replace the ECM.
    • If greater than the specified range, test the 5 volt reference circuit for a short to voltage. If the circuit/connections test normal, replace the ECM.
  8. Test for greater than 80 mA between the 5 volt reference circuit terminal 4 and the low reference circuit terminal 3.
    • If less than the specified range, test the 5 volt reference circuit for a high resistance. If the circuit/connections test normal, replace the ECM.
  9. Install a 3A fused jumper wire between the 5 volt reference circuit terminal 4 and the signal circuit terminal 5. Verify the scan tool MAF sensor voltage parameter is between 4.8-5.2 volts.
    • If not within the specified range, test the signal circuit for a high resistance. If the circuit/connections test normal, replace the ECM.
  10. If all circuits/connections test normal, replace the MAF sensor.
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