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Home >> Pontiac >> 2009 >> G3 Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls And Fuel - 1.6L (LXV) >> Diagnostic Information and Procedures >> DTC P0449 >> Circuit/System Testing
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Circuit/System Testing

  1. Ignition OFF, disconnect the harness connector at the EVAP vent solenoid.
  2. Ignition ON, verify a test lamp illuminates between the ignition 1 voltage circuit terminal A and ground.
    • If the test lamp does not illuminate, test the ignition 1 voltage circuit for a short to ground or an open/high resistance. If the circuit tests normal and the ignition 1 voltage circuit fuse is open, test all components connected to the ignition 1 voltage circuit and replace as necessary.
  3. Connect a DMM, set on the diode setting, between the EVAP vent solenoid control circuit terminal B and ground. The voltage should be greater than 2 volts.
    • If the DMM displays OL, test the control circuit for a short to voltage or an open/high resistance. If the circuit/connections test normal, replace the ECM.
    • If less than the specified range, test the control circuit for a short to ground. If the circuit tests normal, replace the ECM.
  4. Command the EVAP vent solenoid ON and OFF with a scan tool. The DMM should transition from greater than 2 volts when commanded OFF to less than 1 volt, when commanded ON.
    • If the circuit voltage does not correspond to the specified values, replace the ECM.
  5. If all circuits test normal, test or replace the EVAP vent solenoid.
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