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Home >> Buick >> 2008 >> Allure CXS >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System & Fuel System - 3.6L - DTC P0335 To DTC P2097 >> DTC P0446 >> Circuit/System Testing
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Circuit/System Testing

  1. Verify DTCs P0458, P0459, P0498, P0499, P0452, or P0453 are not set.
  2. Disconnect the purge line from the EVAP purge valve.
  3. Ignition ON, observe the fuel tank pressure sensor parameter with a scan tool. The FTP sensor parameter should be 0 inches H2O. If the pressure is not at 0 inches H2O, verify the FTP sensor voltage is less than 4.7 volts.
  4. Reconnect all previously disconnected EVAP hardware.
    5. IMPORTANT: Refer to the J 41413-200  Evaporative Emissions System Tester (EEST) operation manual for detailed instructions. See Special Tools .
  5. Remove the fuel fill cap and connect the GE-41415-50  to the fuel tank filler neck. Connect the J 41413-200  to the GE-41415-50  . See Special Tools .
  6. Ignition ON, seal the EVAP system with a scan tool.
  7. Turn the nitrogen/smoke valve on the J 41413-200  to nitrogen. See Special Tools .
    8. IMPORTANT: DO NOT exceed the specified value in this step. Exceeding the specified value may produce incorrect test results.
  8. Use the remote switch to activate the J 41413-200  and pressurize the fuel tank with nitrogen to 5 inches H2O. See Special Tools .
  9. While observing the FTP sensor parameter with a scan tool, command the EVAP vent valve OFF. Verify the FTP Sensor parameter is 0 inches H2O.
    • If not at the specified value, test for a blockage or a restriction in the EVAP vent hose, or replace the EVAP vent solenoid valve.
  10. Operate the vehicle within the conditions for running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that are captured in the Freeze Frame/Failure Records Data List.
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