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Home >> Oldsmobile >> 2000 >> Intrigue GL >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Tests >> DTC P0442: EVAP System Small Leak Detected >> Diagnostic Procedures

Diagnostic Procedures

  1. Perform On-Board Diagnostic (OBD) system check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
  2. Using scan tool, check if other EVAP system related DTCs (DTC P0440, P0443, P0446, P0449, P0452, P0453, P0462, P0463 or P1441) are set as history DTC. If DTCs are present, diagnose affected DTCs. If DTCs are not present, go to next step.
  3. Check for loose, incorrect, defective or missing fuel filler cap. Check for misrouted, kinked or damaged EVAP system purge lines. Repair as necessary. After repairs, go to step  15. If no problems were found, go to next step.
  4. Using scan tool, perform SERVICE BAY TEST for EVAP system. If vehicle passes service bay test, fault is intermittent. See DIAGNOSTIC AIDS . If vehicle does not pass the service bay test, go to next step.
  5. Turn ignition off. Disconnect EVAP purge line from EVAP purge solenoid valve. Connect a hand-held vacuum pump to purge connection of EVAP purge solenoid valve. Using vacuum pump, apply vacuum. If 12 in. Hg of vacuum can be obtained and held, go to next step. If 12 in. Hg of vacuum cannot be obtained or held, go to step  10.
  6. Turn ignition off. Reconnect EVAP purge solenoid valve lines. Disconnect fuel tank vapor and EVAP purge line from EVAP vapor canister. Plug canister fitting for fuel tank vapor line. Connect a hand-held vacuum pump to EVAP purge line canister fitting. Turn ignition on. Using scan tool, command EVAP vent valve closed. Using vacuum pump, apply vacuum. If 5 in. Hg of vacuum can be obtained and held, go to step  9. If vacuum cannot be obtained and held, go to next step.
  7. Leave system connected. Disconnect vent line at EVAP vent valve. Plug vent line. Using vacuum pump, apply vacuum. If 5 in. Hg of vacuum can be obtained and held, go to step  11. If vacuum cannot be obtained and held, go to next step.
  8. Inspect EVAP vent line from canister to vent valve for leaks. Replace as necessary. After repairs, go to step  15. If vent line is okay, go to step  12.
  9. Install EVAP Pressure/Purge Diagnostic Station (J-41413) and Ultrasonic Leak Detector (J-41416). Ensure gauges on test equipment is zeroed before starting test. Turn ignition off. Remove hand-held vacuum pump. Reconnect EVAP vapor canister purge and tank vent lines. Connect diagnostic station to EVAP system service port. Using scan tool, command EVAP vent valve closed. Continuously attempt to pressurize EVAP system by leaving EVAP Pressure/Purge Diagnostic Station control knob to PRESSURIZE position. Using ultrasonic leak detector, locate EVAP system leak. Repair as necessary. After repairs, go to step  15. If leak is not present, go to step  13.
  10. Check EVAP purge solenoid valve and purge line for carbon contamination. Replace EVAP purge solenoid valve. After replacing solenoid valve, go to step  15.
  11. Replace EVAP vent valve. After replacing vent valve, go to step  15.
  12. Replace EVAP vapor canister. After replacing vapor canister, go to step  15.
  13. Relieve all system pressure. Using scan tool, use Purge/Seal function to turn EVAP purge solenoid valve on to varying vacuum levels with engine running and quickly seal system with scan tool. While system is sealed, compare EVAP pressure/purge diagnostic station's vacuum gauge to vacuum shown on scan tool from the EVAP fuel tank pressure sensor. If fuel tank pressure sensor indicates actual amount of pressure in EVAP system, go to step  3. If fuel tank pressure sensor does not indicate actual amount of pressure in EVAP system, go to next step.
  14. Replace fuel tank pressure sensor. After replacing sensor, go to next step.
  15. Using scan tool, select DTC, CLEAR INFO function. Start engine and allow it to reach operating temperature. Using scan tool, select DTC, SPECIFIC function and enter DTC P0442. Operate vehicle within conditions required to set DTC. If scan tool displays RAN AND PASSED, go to next step. If scan tool does not display RAN AND PASSED, return to step  2.
  16. Using scan tool, review CAPTURED INFO function. If any undiagnosed DTCs are displayed, diagnose affected DTCs. If no DTCs are displayed, system is okay.
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