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Home › Chevrolet › 2006 › Impala LTZ › Repair and Diagnosis › Engine Performance › System › Engine Control System - 3.9L - DTC P0010 To DTC P0420 › DTC P0102 or P0103 › Circuit/System Testing

Circuit/System Testing

  1. Inspect for any contamination, water intrusion, or debris on the sensing elements of the MAF sensor.
    • If debris is present, clean the sensor. If the sensor cannot be cleaned, replace the sensor.
  2. Inspect the fuse in the ignition 1 voltage circuit of the MAF sensor.
    • If the fuse is open, test the ignition 1 voltage circuit for a short to ground.
  3. Turn OFF the ignition. Disconnect the MAF/intake air temperature (IAT) sensor. Start the engine.
  4. Observe the MAF/IAT sensor with a scan tool for 0 Hz.
    • If more than 0 Hz, turn OFF the ignition and inspect the harness for improper routing that is too close to any aftermarket accessories, secondary ignition wires, coils, solenoids, relays, or motors.
  5. Turn ON the ignition, with the engine OFF.
  6. Measure the battery voltage with a DMM.
  7. Connect a test lamp between the ignition 1 voltage circuit of the MAF sensor and a good ground.
  8. Connect the DMM to the probe of the test lamp and good ground, and measure for battery voltage.
    • If not within 0.5 volt of battery voltage, repair the high resistance or open in the MAF sensor ignition 1 voltage circuit.
  9. Turn OFF the ignition and all accessories for 60 seconds to allow the control module to power down.
  10. Measure for 5 ohms of resistance from the ground circuit of the MAF sensor to a good ground with a DMM.
    • If the resistance is more than 5 ohms, repair the high resistance or the open in the MAF sensor ground circuit.
  11. Turn ON the ignition, with the engine OFF.
  12. Measure for 4.8-5.2 volts from the signal circuit of the MAF sensor to a good ground with a DMM.
    • If more than 5.2 volts, test the circuit for a short to voltage, or faulty control module.
    • If less than 4.8 volts, test the circuit for an open, short to ground, or a faulty control module.
    IMPORTANT: To set up the J 38522  variable speed generator, place the duty cycle to normal, the frequency to 5 K, and the signal switch to 5 volts.
  13. Turn OFF the ignition and connect the red lead of the J 38522  to the signal circuit at the MAF sensor harness connector and the black lead to good ground.
  14. Start the engine and observe the MAF sensor parameter for 4,950-5,025 Hz with a scan tool.
    • If the MAF sensor is not within the specified parameter range, test for intermittent or poor connection at the control module. If tests OK, replace the control module.
    • If the MAF sensor is within the specified parameter range, test for intermittent or poor connection at the MAF sensor. If tests OK, replace the MAF sensor.
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