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Home >> Cadillac >> 2007 >> Escalade EXT >> Repair and Diagnosis >> External Pages >> Different car >> Section 28 (Engine Control System - Self-Diagnostics) >> Diagnostic Tests >> DTC P0442: EVAP System - Small Leak Detected >> Diagnostic Procedures
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Diagnostic Procedures

WARNING: This page is about a different car, the 2003 Pontiac Vibe. However, it is still accessible from the selected car via links, so may be relevant.
  1. Did you perform the Diagnostic System Check - Engine Controls? If yes, go to next step. If no, perform diagnostic system check - engine controls. See DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS  under SELF-DIAGNOSTIC SYSTEM.
  2. Install scan tool. Check for DTCs. Is a DTC P0450 or P0451 present? If yes, see DTC P0450: FUEL TANK PRESSURE SENSOR CIRCUIT  or DTC P0451: FUEL TANK PRESSURE SENSOR PERFORMANCE  . If no, go to next step.
  3. Review freeze frame/failure records. Diagnose DTC captured in freeze frame/failure records first. Is DTC P0442 captured in freeze frame/failure records? If yes, go to next step. If no, go to DIAGNOSTIC TROUBLE CODE DEFINITIONS .
  4. Check EVAP system for the following conditions:
    • A loose, missing, or damaged service port Schrader valve.
    • A loose, incorrect, missing, or damaged fuel fill cap.
    • A damaged EVAP purge solenoid.
    Raise and support vehicle on a hoist. Check EVAP system for the following conditions:
    • Any disconnected, improperly routed, kinked, or damaged EVAP pipes and hoses.
    • A damaged EVAP vent solenoid or EVAP canister.
    Did you find and correct the condition? If yes, go to step  10. If no, go to next step.
    5. NOTE: Ensure vehicle underbody temperature is similar to ambient temperature and allow surrounding air to stabilize before starting the diagnostic procedure. System flow will be less with higher temperatures.
  5. Connect the nitrogen/smoke supply hose of Evaporative Emission System Tester (EEST - J 41413-200), or equivalent, to EVAP service port. Turn nitrogen/smoke valve on the control panel to SMOKE. Use remote switch to introduce smoke into EVAP system. Continue to introduce smoke until a steady flow of smoke is seen exiting EVAP canister drain hose. See Figure. Plug EVAP canister drain hose using Plug (J 41413-301), or equivalent. Turn nitrogen/smoke valve on control panel to NITROGEN. Use remote switch to introduce Nitrogen gas into EVAP system for 60 seconds. Check entire EVAP system for exiting smoke with a High Intensity White Light (J 41413-SPT), or equivalent. Continue to introduce smoke, then Nitrogen, at 60 second intervals, until the source of the leak has been located. Did you locate and repair a leak source? If yes, go to step  10. If no, go to next step.
  6. Remove fuel fill cap. Observe FTP in. H20 using scan tool. Is the FTP in. H20 near 0.09 in. H2O? If yes, go to next step. If no, go to step  9.
  7. Install fuel fill cap on fuel fill pipe. Turn nitrogen/smoke valve on EEST control panel to NITROGEN. Use EEST to pressurize EVAP system to 10 in. H2O. Is the FTP parameter more than 5 in. H2O? If yes, go to next step. If no, go to step  9.
  8. Use remote switch to stop introducing nitrogen into EVAP system. Command EVAP purge solenoid ON. Is the FTP sensor parameter less than one in. H2O? If yes, go to DIAGNOSTIC AIDS . If no, go to next step.
  9. Replace FTP sensor. After repair, go to next step.
    10. NOTE: Ensure vehicle underbody temperature is similar to ambient temperature and allow surrounding air to stabilize before starting the diagnostic procedure. System flow will be less with higher temperatures.
  10. Connect the nitrogen/smoke supply hose of EEST (J 41413-200), or equivalent, to EVAP service port. Plug EVAP canister drain hose using Plug (J 41413-301), or equivalent. See Figure. Turn nitrogen/smoke valve to NITROGEN. Pressurize EVAP system to 5 in. H2O. Observe EEST pressure/vacuum gauge for 5 minutes. Does pressure/vacuum gauge remain constant? If yes, go to next step. If no, go to step  5.
  11. Observe CAPTURE INFO using scan tool. Are there any DTCs that have not been diagnosed? If yes, go to DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, system is okay at this time.
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