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Home >> Hummer >> 2009 >> H3 Alpha >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls And Fuel - 5.3L - DTC P0315 To DTC P064A >> DTC P0443 or P0449 >> Circuit/System Testing
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Circuit/System Testing

  1. Ignition OFF, disconnect the harness connector at the EVAP canister purge or vent solenoid valve.
  2. Ignition ON, verify that a test lamp illuminates between the voltage supply circuit terminal A and ground.
    • If the test lamp does not illuminate, test the voltage supply circuit for a short to ground or an open/high resistance. If the circuit tests normal and the voltage supply circuit fuse is open, test or replace the EVAP canister purge solenoid.
  3. Connect a test lamp between the voltage supply circuit terminal A and the control circuit terminal B.
  4. Command the EVAP canister purge solenoid valve to 50 percent with a scan tool, or the EVAP canister vent solenoid valve ON and OFF. The test lamp should respond to the command.
    • If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the ECM.
    • If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.
  5. If all circuits test normal, replace the appropriate solenoid valve.
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