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Home >> Hummer >> 2008 >> H2 4D Utility Wagon >> Repair and Diagnosis >> External Pages >> Different car >> Section 141 (Engine Control System & Fuel - 4.8L, 5.3L, 6.0L And 6.2L - DTC P0010 To DTC P0333) >> DTC P0101 or P1101 >> Circuit/System Testing

Circuit/System Testing

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  1. If P0106 or P0121 is set, diagnose first.
  2. Turn ON the ignition, with the engine OFF.
  3. Measure the battery voltage.
  4. Disconnect the MAF sensor.
  5. Connect a test lamp between the MAF sensor ignition 1 voltage circuit and a good ground.
  6. With the test lamp still connected, measure for battery voltage between the ignition 1 voltage circuit and a good ground.
    • If the voltage is not within 0.75 volts of battery voltage, repair the high resistance in the circuit.
  7. Measure the voltage between the MAF sensor signal circuit and a good ground for 4.9-5.2 volts.
    • If the voltage is less than 4.9 volts, test the circuit for high resistance, or an open.
    • If the voltage is within 4.9-5.2 volts, test the circuit for a short to the IAT signal circuit or to any other 5-volt reference circuit.
  8. Turn OFF the ignition and all electrical accessories. Allow sufficient time for the control module to power down before taking a resistance measurement.
  9. Measure the resistance between the ground circuit of the MAF sensor and a good ground for less than 5 ohms of resistance. You should measure less than 5 ohms of resistance.
    • If the resistance is more than 5 ohms, repair the high resistance in the ground circuit.
    10. IMPORTANT: To set up the J 38522  , place the duty cycle to normal, the frequency to 5K, and the signal switch to 5 volts. See Special Tools .
  10. Turn OFF the ignition and connect the red lead of the J 38522  to the signal circuit of the MAF sensor harness connector and the black lead to a good ground. See Special Tools .
  11. Start the engine and observe the MAF sensor for a range of 4,950-5,025 Hertz.
    • If the MAF sensor is not within the specified range, test for intermittent or poor connections at the control module. If test OK, replace the control module.
    • If the MAF sensor is within the specified range, test for intermittent or poor connections at the control module. If test OK, replace the MAF sensor.
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