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Home >> Chevrolet >> 2011 >> Caprice >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls And Fuel - 6.0L - DTC Diagnostics And Troubleshooting >> Diagnostic Information and Procedures >> DTC P0443 or P0449 >> Circuit/System Testing

Circuit/System Testing

  1. Ignition OFF, disconnect the harness connector at,
    • The Q12 evaporative emission purge solenoid valve for P0443
    • The Q13 evaporative emission vent solenoid valve for P0449
  2. Ignition ON, verify that a test lamp illuminates between the voltage supply circuit terminal 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 all components connected to the voltage supply circuit and replace as necessary.
  3. Connect a test lamp between the voltage supply circuit terminal and the control circuit terminal.
  4. With a scan tool command the,
    • EVAP purge solenoid valve to 50 %
    • EVAP vent solenoid valve to OFF (Venting) and ON (Not Venting)

      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 K20 engine control module.
    • 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 K20 engine control module.
  5. If all circuits test normal, replace the appropriate solenoid valve.
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