LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Hummer >> 2009 >> H3T Alpha >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls And Fuel - 5.3L - DTC P0016 To DTC P0308 >> DTC P0102 or P0103 >> Circuit/System Testing
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Circuit/System Testing

NOTE: All electrical components and accessories must be turned OFF and allowed to power down.
  1. Ignition OFF, disconnect the MAF/IAT harness connector at the MAF/IAT sensor.
  2. Ignition OFF for 90 seconds, test for less than 5 ohms between the ground circuit terminal B and ground.
    • If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal C and ground.
    • If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance.
  4. Ignition ON, test for 4.8-5.2 volts between the signal circuit terminal A and ground.
    • If less than the specified range, test the signal circuit terminal A 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 signal circuit for a short to voltage. If the circuit tests normal, replace the ECM.
  5. 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.
  6. Set the J 38522  signal to 5 volts, the Frequency to 5K, and the Duty Cycle to Normal.
  7. Engine idling, observe the scan tool MAF Sensor parameter. The scan tool MAF Sensor parameter should be between 4,950-5,025 Hz.
    • If the MAF Sensor parameter is not within the specified range, replace the ECM.
  8. If all other circuits test normal, replace the MAF sensor.
scientia non olet · About LEMON Manuals