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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 378 (Engine Controls Self-Diagnostics - 3.1L Engine) >> Diagnostic Tests >> DTC P0442: Evaporative Emission Control System - Small Leak Detected >> Diagnostic Procedure

Diagnostic Procedure

WARNING: This page is about a different car, the 2003 Pontiac Grand Prix, 2003 Chevrolet Malibu, and 2003 Buick Century. However, it is still accessible from the selected car via links, so may be relevant.
  1. Perform diagnostic system check - engine controls. See DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS  under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check - engine controls, go to next step.
  2. Perform the Service Bay Test. Go to SERVICE BAY TEST  under DRIVE CYCLES. Does the scan tool indicate that the service bay test passed? If yes, go to next step.
  3. 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 canister purge solenoid.

    Raise and support vehicle on hoist. Check EVAP system for the following conditions:

    • Any disconnected, improperly routed, kinked, or damaged EVAP pipes and hoses.
    • A damaged EVAP canister vent solenoid or EVAP canister.

    Did you find and correct the condition? If yes, go to step  6. If no, go to next step.

    4. 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.
  4. Turn ignition switch to OFF position. Connect the Evaporative Emissions System Tester (EEST) (J 41413-200), or equivalent, power supply clips to a known good 12-volt source. Install the Fuel Tank Cap Adapter (J 41415-40), or equivalent, to the fuel fill pipe. Connect the fuel fill cap to the fuel tank cap adapter. Connect the EEST nitrogen/smoke supply hose to the fuel tank cap adapter. Turn ignition switch to RUN position, engine OFF. Command the EVAP vent solenoid closed using a scan tool. Turn the nitrogen/smoke valve on the EEST 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), or equivalent, 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. Check the entire EVAP system for exiting smoke using the High Intensity White Light (J 41413-SPT), or equivalent. 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  6. If no, go to next step.
  5. Disconnect the fuel tank cap adapter from the fuel fill pipe. Install the fuel fill cap to the fuel fill pipe. Connect the EEST nitrogen/smoke supply hose to the EVAP service port. Use the remote switch to introduce smoke into the EVAP system. Check the entire EVAP system for exiting smoke using the high intensity light. 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, go to DIAGNOSTIC AIDS .
  6. Perform the Service Bay Test. Go to SERVICE BAY TEST  under DRIVE CYCLES. Does the scan tool indicate that the service bay test passed? If yes, go to next step. If no, go to step  3.
  7. Using the scan tool, observe the stored information in CAPTURE INFO. Does the scan tool display any DTCs that you have not diagnosed? If yes, see DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, system is okay at this time.
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