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Home >> Oldsmobile >> 2003 >> Bravada AWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - Self-Diagnostics - 4.2L >> Diagnostic Tests >> DTC P0442: EVAP System - Small Leak Detected >> Diagnostic Procedures

Diagnostic Procedures

  1. Did you perform the Diagnostic System Check - Engine Controls? If yes, go to next step. If no, see DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS  under SELF-DIAGNOSTIC SYSTEM.
  2. Inspect the EVAP system for the following conditions:
    • A loose, incorrect, faulty, or missing fuel tank fill cap.
    • Damaged or disconnected EVAP system purge lines.
    • A damaged EVAP system component.
    • A loose, missing, or damaged service port Schrader valve.

    Did you find and correct the condition? If yes, go to step  5. If no, go to next step.

    3. NOTE: Ensure that the vehicle underbody temperature is similar to the ambient temperature and allow the surrounding air to stabilize before starting the diagnostic procedure. System flow will be less with higher temperatures.
  3. Turn ignition off. Connect the Evaporative Emissions System Tester (J-41413-200) power supply clips to a known-good 12-volt source. Install the Fuel Tank Cap Adapter (J-41415-40) to the fuel fill pipe. Connect the fuel fill cap to the Fuel Tank Cap Adapter. Connect the Evaporative Emissions System Tester nitrogen/smoke supply hose to the Fuel Tank 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 SMOKE. Use the remote switch to introduce smoke into the EVAP system. Use the EVAP Service Port Vent Fitting (J-41413-VLV) to open the EVAP service port. Remove the EVAP Service Port Vent Fitting once smoke is observed. Continue to introduce smoke into the EVAP system for an additional 60 seconds. Inspect the entire EVAP system for exiting smoke with the High Intensity White Light (J-41413-SPT). Continue to introduce smoke at 15 second intervals until the leak source has been located. Did you locate and repair a leak source? If yes, go to step  5. If no, go to next step.
  4. Disconnect the Fuel Tank Cap Adapter from the fuel fill pipe. Install the fuel fill cap to the fuel fill pipe. Connect the Evaporative Emissions System Tester nitrogen/smoke supply hose to the EVAP service port. Use the remote switch to introduce smoke into the EVAP system. Inspect the entire EVAP system for exiting smoke with the High Intensity White Light (J-41413-PT). Continue to introduce smoke at 15 second intervals until the leak source has been located. Did you locate and repair a leak source? If yes, go to next step. If no, see DIAGNOSTIC AIDS .
    5. NOTE: Larger volume fuel tanks and/or those with lower fuel levels may require several minutes for the floating indicator to stabilize.
  5. Turn the nitrogen/smoke valve to nitrogen. Connect the nitrogen/smoke hose to the 0.20" (0.5 mm) test orifice on the bottom front of the Evaporative Emissions System Tester. Use the remote switch to activate the Evaporative Emissions System Tester. Align the Red flag on the flow meter with the floating indicator. Use the remote switch to de-activate the Evaporative Emissions System Tester. Install the Fuel Tank Cap Adapter to the fuel fill pipe. Remove the nitrogen/smoke hose from the test orifice and install the hose onto the Fuel Tank Cap Adapter. Turn ignition on, with engine off. Command the EVAP vent solenoid closed with a scan tool. Use the remote switch to introduce nitrogen and fill the EVAP system until the floating stabilizes. Compare the flow meter's stable floating indicator position to the Red flag. Is the floating indicator below the Red flag? If yes, go to next step. If no, go to step  2.
  6. Observe the stored information, Capture Info with scan tool. Does scan tool display any DTCs that you have not diagnosed? If yes, see DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, system is okay.
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