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Home >> Cadillac >> 2002 >> Escalade EXT >> Repair and Diagnosis >> External Pages >> Different car >> Section 88 (Engine Control System Self-Diagnostics - 3.8L) >> Diagnostic Tests >> DTC P0442: EVAP System Small Leak Detected >> Diagnostic Procedures
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Diagnostic Procedures

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  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. Does the scan tool indicate DTCs P0443, P0449, P0452, P0453, or P1441 are also set? If yes, see DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, go to next step.
  3. Inspect EVAP system for the following conditions:
    • Loose, missing, or damaged service port dust cap and/or Schrader valve.
    • Loose, incorrect, missing, or damaged fuel fill cap.
    • Damaged EVAP canister purge valve.

    Raise the vehicle on a hoist. Inspect the EVAP system for the following conditions:

    • Disconnected, improperly routed, kinked, or damaged EVAP pipes and hose.
    • Damaged EVAP canister vent valve or EVAP canister.

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

  4. With a scan tool, capture and record the fail record data and clear the DTCs. Perform the SERVICE BAY TEST using scan tool. Does the scan tool indicate that the service bay test passed? If yes, see DIAGNOSTIC AIDS . If no, go to next step.
    5. NOTE: Always zero EVAP pressure and vacuum (in. H2O) gauges on EVAP pressure and purge station before proceeding with diagnosis.
    NOTE: Fuel tank may need to be partially lowered to inspect components located in upper portion of tank.
  5. Install Fuel Tank Cap Adapter (J 41415-40). Connect EVAP Pressure and Purge Station (J 41413) to fuel tank cap adapter. Turn ignition on, engine off. Using scan tool, seal EVAP system. Using EVAP pressure and purge station, continuously pressurize EVAP system to 15 in. H2O. Using Ultrasonic Leak Detector (J 41416), inspect for leaks in the following locations:
    • EVAP system purge pipe.
    • EVAP vapor pipe.
    • EVAP vent hose.
    • Fuel fill pipe/hose and fuel fill cap.
    • EVAP canister.
    • EVAP canister vent valve.
    • EVAP canister purge valve.
    • Fuel sender assembly and/or seal.
    • Fuel Tank Pressure (FTP) sensor seal.
    • Fill limiter vent valve, pressure relief valve, rollover valve, or fuel tank.

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

  6. With a scan tool, capture and record the fail record data and clear the DTCs. Perform the SERVICE BAY TEST using scan tool. Does the scan tool indicate that the service bay test passed? If yes, go to next step. If no, go to step  5.
  7. Using scan tool, observe stored information. Does scan tool displays any DTCs that have not been diagnosed? If yes, see DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, system is okay.
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