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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 102 (Engine Controls - Self-Diagnostics - 3.5L) >> Diagnostic Tests >> DTC P0440: EVAP System >> Diagnostic Procedures

Diagnostic Procedures

WARNING: This page is about a different car, the 2002 Oldsmobile Intrigue and 2002 Oldsmobile Aurora. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: EVAP Pressure/Purge Diagnostic Station (J- 41413) is required to pressurize EVAP system in the following test.
  1. Did you perform the Diagnostic System Check - Engine Controls? If yes, go to next step. If no, go to DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS  under SELF-DIAGNOSTIC SYSTEM.
  2. If DTC P0443 or DTC P0449 is also set, see DTC P0443: EVAP PURGE SOLENOID CONTROL CIRCUIT  or DTC P0449: EVAP CANISTER VENT SOLENOID CONTROL CIRCUIT  . If DTC P0443 or DTC P0449 is not set, go to next step.
  3. Inspect EVAP system for the following conditions. Check for loose, missing or damaged service port Schrader valve. Check for loose, incorrect, missing or damaged fuel filler cap. Check for damaged EVAP canister purge valve. Raise and support vehicle. Check for disconnected, improperly routed, kinked or damaged EVAP pipes and hoses. Check for damaged EVAP canister vent valve. EVAP canister vent valve is located near fuel tank. Check for damaged EVAP canister. EVAP canister is located near fuel tank. If any problems are found, repair as necessary. After repairs, go to  18. If no problems are found, go to next step.
  4. With a scan tool, capture and record the Fail Record data and clear DTCs. Perform the Service Bay Test using scan tool. Does scan tool indicate that the Service Bay Test passed? If yes, see DIAGNOSTIC AIDS . If no, go to next step.
  5. Remove fuel filler cap. Install Fuel Tank Cap Adapter (J-41415). Connect EVAP Pressure/Purge Station (J-41413). Install vehicle fuel filler cap to fuel fill cap adapter. Zero pressure and vacuum gauges on EVAP pressure/purge station. Turn ignition on. Using scan tool, seal EVAP system. Using EVAP pressure/purge diagnostic station, pressurize system to 5 in. H2O. Rotate EVAP pressure/purge diagnostic station rotary switch to OFF/HOLD position. Monitor pressure gauge for one minute. If pressure stays at 5 in. H2O, go to next step. If pressure does not stay at 5 in. H2O, go to step  9.
  6. Compare the J-41413 value to scan tool FTP sensor value. Does the J-41413 value measure near the scan tool value? If yes, go to next step. If no, go to step  11.
  7. Monitor the pressure gauge on the J-41413 EVAP Pressure/Purge Diagnostic Station. Disconnect EVAP purge pipe from EVAP purge valve. Does EVAP system pressure decrease? If yes, go to step  9. If no, go to step  10.
    8. NOTE: It may be necessary to partially lower fuel tank to inspect components located in the upper portion of tank.
  8. Continuously pressurize the EVAP system with the J-41413. Using Ultrasonic Leak Detector (J-41416), check for leaks with in EVAP system purge pipe, vapor pipe, vent hose/pipe, fuel fill pipe/hose and cap, EVAP canister, EVAP canister vent valve, canister purge valve, fuel sender assembly and/or seal FTP sensor seal, fill limiter vent valve, pressure relief valve, rollover valves, permanent EVAP pipes and/or fuel tank. Did you locate and repair a leak? If yes, go to step  17. If no, see DIAGNOSTIC AIDS .
  9. Connect a vacuum gauge to EVAP purge valve purge pipe port. Start engine and allow it to idle. Using scan tool, command EVAP canister purge valve to 50 percent. If vacuum gauge indicates an increase in vacuum, see DIAGNOSTIC AIDS . If vacuum gauge does not indicate an increase in vacuum, go to step  15.
  10. Monitor pressure gauge on EVAP pressure/purge diagnostic station. Disconnect purge pipe from EVAP canister. Does EVAP system pressure decreases? If yes, go to step  16. If no, go to next step.
  11. Monitor pressure gauge on EVAP pressure/purge diagnostic station. Disconnect vapor pipe from EVAP canister. If EVAP system pressure decreases, go to  17. If EVAP system pressure does not decrease, go to step  14.
  12. Using scan tool, monitor FTP sensor voltage. Is voltage more than 4.3 volts? If yes, go to DTC P0453: FUEL TANK PRESSURE SENSOR CIRCUIT - HIGH VOLTAGE . If no, go to next step.
  13. Replace FTP sensor. FTP sensor is located on top of fuel tank and can be accessed through an inspection panel in trunk. After repairs, go to step  18.
  14. Repair pinched or obstructed EVAP vapor pipe. After repairs, go to step  18.
  15. Replace EVAP canister purge valve. After repairs, go to step  18.
  16. Repair restriction in EVAP purge pipe. After repairs, go to step  18.
  17. Replace EVAP canister. After repairs, go to next step.
  18. Using scan tool, capture and record the Fail Record data and clear DTCs. Perform the Service Bay Test using scan tool. Does scan tool indicate that Service Bay Test passed? If yes, go to next step. If no, go to step  5.
  19. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, system is okay. If any other DTCs are set, repair DTCs as necessary. See DIAGNOSTIC TROUBLE CODE DEFINITIONS .
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