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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 1991 (Engine Controls And Fuel - 3.6L (LCS) - DTC P0192 To DTC P0629) >> DTC P0449, P0498, or P0499 >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2009 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF, open the hood to disable the Auto-Stop function.
  2. Ignition ON, verify the scan tool hood position parameter displays Open.
    • If the hood position does not display Open, refer to DTC P254F .
  3. Ignition OFF, disconnect the harness connector at the EVAP vent solenoid valve.
  4. Ignition ON, verify that a test lamp illuminates between the ignition voltage circuit terminal B and ground.
    • If the test lamp does not illuminate, 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. Test for 3-4 V between the control circuit terminal A and ground.
    • If less than the specified range, test the control circuit for a short to ground or an open/high resistance. If circuit tests normal, replace the ECM.
    • If greater than the specified range, test the control circuit for a short to voltage. If circuit test normal, replace the ECM.
  6. Command the EVAP vent solenoid valve ON and OFF with a scan tool. The DMM should transition from 3-4 V when ON to less than 0.1 V when commanded OFF.
    • If the circuit voltage does not correspond to the specified values, replace the ECM.
  7. If all circuits test normal, test or replace the EVAP vent solenoid valve.
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