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Home >> Chevrolet >> 2006 >> Chevy Express G2500, Van Cargo Extended, 6.6 2 >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - 6.6L (LLY) - DTC P0016 To DTC P0342 >> DTC P0101 >> Circuit/System Testing

Circuit/System Testing

IMPORTANT:
  • If DTC P0405 is set, diagnose that DTC first.
  • The DMM and test leads must be calibrated to 0 ohms in order to prevent misdiagnosis. Use the DMM to perform this test. Refer to the DMM User Manual for the calibration procedure.
  • Use the J 35616-200  for this test. If the J 35616-200  is not available, use a test lamp that measures more than 20 ohms.
  1. With the ignition ON, the engine OFF, the mass air flow (MAF) sensor disconnected, connect a test lamp between the MAF sensor 12-volt reference circuit and a good ground. Measure the voltage of the MAF sensor 12-volt reference circuit at the probe end of the test lamp, with a DMM connected to a good ground.
    • If the voltage is less than battery voltage, test the circuit for a high resistance or a faulty ECM.
  2. With the MAF sensor still disconnected, use the scan tool to observe the MAF Sensor parameter.
    • If the MAF Sensor parameter is more than 0 volts, test the MAF sensor signal circuit for a short to voltage or a faulty ECM.
  3. Connect a jumper wire between the MAF sensor signal circuit and the IAT sensor signal circuit. Use a scan tool to observe the MAF Sensor parameter for the proper value of more than 4.7 volts and 500 g/s.
    • If the MAF Sensor parameter is less than 4.7 volts and 500 g/s, test the MAF sensor signal circuit for a high resistance or a faulty ECM.
  4. Turn OFF the ignition, and all electrical accessories. Allow sufficient time for the control module to power down before taking a resistance measurement. With a DMM, measure the resistance between the low reference circuit of the MAF sensor and a good ground.
    • If the resistance is more than 1.5 ohms, test the circuit for a high resistance or a faulty ECM.
    • If the MAF sensor circuits test normal, replace the MAF sensor. Refer to Repair Instructions in this diagnostic.
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