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Home › Saturn › 2003 › LW200 › Repair and Diagnosis › Engine Performance › System › Engine Controls - Self-Diagnostics › Diagnostic Tests › DTC P0446: EVAP Vent Solenoid Valve Control System › Diagnostic Procedures

Diagnostic Procedures

  1. Did you perform the Diagnostic System Check - Engine Controls? If yes, go to next step. If no, go to DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS  under SELF-DIAGNOSTIC SYSTEM.
  2. Inspect the EVAP system for a damaged EVAP vent solenoid, pinched EVAP vent hose, or damaged EVAP canister. Did you find and correct the condition? If yes, go to step  17. If no, go to next step.
  3. Command the EVAP vent solenoid ON and OFF with a scan tool. Do you hear or feel the EVAP vent solenoid click when commanded ON and OFF? If yes, go to next step. If no, go to step  8.
  4. Turn ignition off. Disconnect the EVAP purge line from the EVAP purge solenoid. Turn ignition on, with engine off. Is the Fuel Tank Pressure Sensor parameter within 2.35-2.85 volts? If yes, go to next step. If no, go to step  10.
    5. NOTE: Do not exceed the specified value in this step. Exceeding the specified value may produce incorrect test results.
  5. Turn ignition off. Connect the EVAP purge pipe. Connect the Evaporative Emissions System Tester (J 41413-100) power supply clips to a known good 12-volt source. Install the Fuel Fill Cap Adapter (J 41415-40) to the fuel fill pipe. Connect the fuel fill cap to the Fuel Fill Cap Adapter. Connect the Evaporative Emissions System Tester nitrogen/smoke supply hose to the Fuel Fill Cap Adapter. Turn ignition on, with engine off. Command the EVAP vent solenoid closed with a scan tool. Turn the nitrogen/smoke valve on the Evaporative Emissions System Tester control panel to NITROGEN. Use the remote switch to pressurize the EVAP system to 5 in. H2O on the gauge of the Evaporative Emissions System Tester. Observe the Fuel Tank Pressure Sensor parameter with a scan tool. Command the EVAP vent solenoid open with a scan tool. Is the Fuel Tank Pressure Sensor parameter within 2.35-2.85 volts? If yes, go to DIAGNOSTIC AIDS . If no, go to next step.
  6. Disconnect the EVAP vent hose from the EVAP vent solenoid. Is the Fuel Tank Pressure Sensor parameter within 2.35-2.85 volts? If yes, go to step  13. If no, go to next step.
  7. Disconnect the EVAP vent hose from the EVAP canister. Is the Fuel Tank Pressure Sensor parameter less than 2.35-2.85 volts? If yes, go to step  12. If no, go to step  14.
  8. Disconnect the EVAP vent solenoid. Probe the control circuit of the EVAP vent solenoid with a test light that is connected to battery voltage. Does the test light illuminate? If yes, go to next step. If no, go to step  13.
  9. Test the EVAP vent solenoid control circuit for a short to ground. Did you find and correct the condition? If yes, go to step  17. If no, go to step  11.
  10. Test for an intermittent and for a poor connection at the Fuel Tank Pressure (FTP) sensor. Did you find and correct the condition? If yes, go to step  17. If no, go to step  15.
  11. Test for an intermittent and for a poor connection at the control module. Did you find and correct the condition? If yes, go to step  17. If no, go to step  16.
  12. Repair pinched or restricted EVAP vent hose. After repairs, go to step  17.
  13. Replace EVAP vent solenoid. After replacement, go to step  17.
  14. Replace EVAP canister. After replacement, go to step  17.
  15. Replace FTP sensor. After replacement, go to step  17.
  16. Replace PCM. See POWERTRAIN CONTROL MODULE in REMOVAL & INSTALLATION - SATURN "L" SERIES article. Perform PCM relearn procedure. See PCM REPROGRAMMING  under PROGRAMMING. After replacing PCM, go to next step.
    17. NOTE: Do not exceed the specified value in this step. Exceeding the specified value may produce incorrect test results.
  17. Turn ignition off. Connect all disconnected components. Connect the Evaporative Emissions System Tester to the fuel fill pipe. Turn ignition on, with engine off. Command the EVAP vent solenoid closed with a scan tool. Turn the nitrogen/smoke valve on the Evaporative Emissions System Tester control panel to NITROGEN. Use the remote switch to pressurize the EVAP system to 5 in. H2O on the gauge of the Evaporative Emissions System Tester. Observe the Fuel Tank Pressure Sensor parameter with a scan tool. Command the EVAP vent solenoid open with a scan tool. Is the Fuel Tank Pressure Sensor parameter within 2.35-2.85 volts? If yes, go to next step. If no, go to step  2.
  18. Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? If yes, go to DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, system is okay.
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