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HOMESERVICE MANUALSCHEVROLET2001CAVALIER LS, 2.4 TREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 86 (ENGINE CONTROLS SELF-DIAGNOSTICS)DIAGNOSTIC TESTSDTC P0440: EVAP SYSTEM - LARGE LEAKDIAGNOSTIC PROCEDURES
2001 Chevrolet Cavalier LS, 2.4 T

Diagnostic Procedures

2001 Chevrolet Cavalier LS, 2.4 TSECTION Diagnostic Procedures
WARNING: This page is about a different car, the 2003 Chevrolet Corvette. 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, see DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS  under SELF-DIAGNOSTIC SYSTEM.
  2. Observe the Freeze Frame/Failure Records for this DTC. Perform the Service Bay Test. See INSPECTION/MAINTENANCE EVAPORATIVE EMISSION SYSTEM SET PROCEDURE  under SELF-DIAGNOSTIC SYSTEM. Does the scan tool indicate that the Service Bay Test passed? If yes, go to DIAGNOSTIC AIDS . If no, go to next step.
  3. Inspect the EVAP system for the following conditions:
    • Loose, missing, or damaged service port Schrader valve.
    • Loose, incorrect, missing, or damaged fuel fill cap.
    • A damaged EVAP purge valve.

    Raise and support the vehicle. Inspect the EVAP system for the following conditions:

    • Disconnected, improperly routed, kinked, or damaged EVAP pipes and hoses.
    • A damaged EVAP vent valve or EVAP canister.

    Did you find and correct the condition? If yes, go to step  19. 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. The system flow will be less with higher temperatures.
  4. Perform the following:
    • Turn ignition OFF.
    • Connect Evaporative Emissions System Tester (EEST) power supply clips to a known good 12-volt source.
    • Install Fuel Tank Cap Adapter to the fuel fill pipe.
    • Install the fuel fill cap to the Fuel Tank Cap Adapter.
    • Connect Evaporative Emissions System Tester nitrogen/smoke supply hose to the Fuel Tank Cap Adapter.
    • Turn ignition ON, with engine OFF.
    • Command EVAP vent valve 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 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 entire EVAP system for exiting smoke with the High Intensity White 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 step  19. If no, go to next step.

  5. Perform the following:
    • 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.
    • 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  19. If no, go to next step.

  6. Peform the following:
    • Use the remote switch to stop introducing smoke.
    • Install the Fuel Tank Cap Adapter to the fuel fill pipe.
    • Connect the Evaporative Emissions System Tester nitrogen/smoke supply hose and vehicle fuel fill cap to the Fuel Tank Cap Adapter.
    • Command the EVAP vent valve open with a scan tool.
    • Compare the Fuel Tank Pressure (FTP) parameter with a scan tool to the Evaporative Emissions System Tester pressure/vacuum gauge.

    Is the scan tool Fuel Tank Pressure parameter within 1 in. H2O? If yes, go to next step. If no, go to step  16.

  7. Seal the EVAP system using the EVAP Purge/Seal function with a scan tool. Turn the nitrogen/smoke valve on the Evaporative Emissions System Tester control panel to NITROGEN. Use the Evaporative Emissions System Tester to pressurize the EVAP system 10 in. H2O. Is the Fuel Tank Pressure sensor parameter more than 5 in. H2O? If yes, go to next step. If no, go to step  16.
  8. Use the remote switch to stop introducing nitrogen into the EVAP system. Increase the EVAP purge valve to 100 percent. Is the Fuel Tank Pressure parameter less than 1 in. H2O? If yes, go to DIAGNOSTIC AIDS . If no, go to next step.
  9. Disconnect the EVAP purge vacuum source from the EVAP purge valve. Is the Fuel Tank Pressure parameter less than 1 in. H2O? If yes, go to step  13. If no, go to next step.
  10. Disconnect the EVAP purge pipe from the EVAP purge valve. Is the Fuel Tank Pressure parameter less than 1 in. H2O? If yes, go to step  17. If no, go to next step.

    Did you locate and repair the system? If yes, go to step  18. If no, see DIAGNOSTIC AIDS .

  11. Disconnect the EVAP purge pipe at the EVAP canister. Is the Fuel Tank Pressure parameter less than 1 in. H2O? If yes, go to step  15. If no, go to next step.
  12. Disconnect the EVAP vapor pipe at the EVAP canister. Is the Fuel Tank Pressure parameter less than 1 in. H2O? If yes, go to step  18. If no, go t step  14.
  13. Repair the pinched or obstructed EVAP purge valve vacuum source. Did you complete the repair? If yes, go to step  19.
  14. Repair the pinched or obstructed EVAP vapor pipe. Did you complete the repair? If yes, go to step  19.
  15. Repair the restriction in the EVAP purge pipe. Did you complete the repair? If yes, go to step  19.
  16. Replace FTP sensor. See FUEL TANK PRESSURE SENSOR under SENSORS in REMOVAL & INSTALLATION - CORVETTE article. Did you complete the replacement? If yes, go to step  19.
  17. Replace the EVAP purge valve. See EVAP CANISTER PURGE VALVE under SOLENOIDS in REMOVAL & INSTALLATION - CORVETTE article. Did you complete the replacement? If yes, go to step  19.
  18. Replace the EVAP canister. See EVAP CANISTER under EMISSION SYSTEMS & SUB-SYSTEMS in REMOVAL & INSTALLATION - CORVETTE article. Did you complete the replacement? If yes, go to next step.
  19. Perform Service Bay Test. See INSPECTION/MAINTENANCE EVAPORATIVE EMISSION SYSTEM SET PROCEDURE  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.
  20. Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? If yes, see DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, system is okay.
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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.