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Home >> Chevrolet >> 2012 >> Cruze Eco, Automatic Trans >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 5 (Engine Controls/Fuel - 1.8L - DTC Diagnostics, Troubleshooting & Diagnosis) >> Diagnostic Information and Procedures >> DTC P0101 (LUW) >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different variant/trim than selected.
  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
    • Objects that block the MAF sensor air inlet
    • An air filter element that is restricted
    • 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 B75B Mass Air Flow/Intake Air Temperature Sensor.
  3. Ignition OFF, all vehicles system OFF. It may take up to 2 minutes for all vehicle systems to power down. Test for less than 5 Ω between the ground circuit terminal 2 and ground.
    • If greater than the specified range, test the ground circuit for an open/high resistance.
  4. Ignition ON, test for B+ between the ignition voltage circuit terminal 4 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 and the ignition voltage circuit fuse is open, test all components connected to the ignition voltage circuit and replace as necessary.
  5. Ignition ON, test for 4.8-5.2 V between the signal circuit terminal 5 and ground.
    • If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 Engine Control Module.
    • If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the K20 Engine Control Module.
  6. Ignition OFF, connect the red lead of the EL 38522  Variable Signal Generator to the signal circuit terminal 5 at the B75B Mass Air Flow/Intake Air Temperature Sensor harness connector. Connect the battery voltage supply to the B+, and ground the black lead.
  7. Set the EL 38522  Variable Signal Generator to the following specifications signal switch to 5 V, the Frequency switch to 5 K, and the duty cycle switch to normal.
    • Signal switch to 5 V
    • Frequency switch to 5 KHz
    • Duty Cycle switch to Normal
  8. Engine idling, observe the scan tool MAF Sensor Hz parameter. The scan tool MAF Sensor parameter should be between 4 950-5 025 Hz.
    • If not within the specified range, replace the K20 Engine Control Module.
  9. If all circuits test normal, test or replace the B75B Mass Air Flow/Intake Air Temperature Sensor.
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