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Home >> Chevrolet >> 2001 >> Camaro Base, 2D Convertible, Automatic >> Repair and Diagnosis >> Engine Performance >> Testing & Diagnosis >> Engine Control System Self-Diagnostics - 3.8L >> Diagnostic Tests >> DTC P0440: Evaporative Emission System >> Diagnostic Procedures

Diagnostic Procedures

  1. If powertrain diagnostic system check was performed, go to next step. If powertrain diagnostic system check was not performed, go to POWERTRAIN DIAGNOSTIC SYSTEM CHECK  under DIAGNOSTIC SYSTEM CHECKS. After performing powertrain diagnostic system check, go to next step.
  2. Check for additional DTCs. If DTC P0443 or DTC P0449 are also set, diagnose those DTCs first. See DIAGNOSTIC TROUBLE CODE DEFINITIONS . If additional DTCs are not set, go to next step.
  3. Check EVAP system for loose, incorrect, defective or missing fuel tank filler cap. Check for improperly routed, kinked or damaged EVAP system purge lines or damaged EVAP system component. Repair or replace as necessary. After repairs, go to step  18. If no problem is found, go to next step.
    NOTE: The following steps require EVAP Pressure/Purge Diagnostic Station (J 41413) and Fuel Fill Cap Adaptor (J 41415). Always zero EVAP pressure and vacuum in H2O gages on EVAP pressure diagnostic station before proceeding with diagnosis.
  4. Connect EVAP pressure/purge diagnostic station and fuel fill cap adapter. Turn ignition on. Using scan tool, seal EVAP system. Pressurize system to 5 in. H2O using EVAP pressure/purge diagnostic station. Rotate EVAP pressure/purge diagnostic station rotary switch to OFF/HOLD position. Monitor pressure gage for 1 minute. If gauge holds steady at 5 in. H2O, go to next step. If gauge does not hold steady at 5 in. H2O, go to step  7.
  5. Compare EVAP pressure/purge diagnostic station value Fuel Tank Pressure (FTP) sensor value on scan tool. If EVAP pressure/purge diagnostic station value is near the scan tool value, go to next step. If EVAP pressure/purge diagnostic station value is not near the scan tool value, go to step  11.
  6. Monitor pressure gage on EVAP pressure/purge diagnostic station. Disconnect EVAP purge pipe from the EVAP purge solenoid. EVAP purge solenoid is located on left side of engine next to cylinder No. 3 fuel injector. If EVAP system pressure decreases, go to step  8. If EVAP system pressure does not decrease, go to step  9.
  7. Using EVAP pressure/purge diagnostic station, continuously pressurize EVAP system. It may be necessary to partially lower fuel tank to inspect components located in upper portion of tank. Using Ultrasonic Leak Detector (J 41416), inspect for leaks in EVAP system purge pipe, vapor pipe, canister, vent hose/pipe, fuel fill pipe/hose and fuel fill cap, canister vent valve, 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. See Figure. Repair as necessary. After repairs, go to step  18. If components are okay and no leak is found, go to DIAGNOSTIC AIDS .
  8. Attach a vacuum gauge to purge pipe port of EVAP purge solenoid. Start engine and allow to idle. Using scan tool, command EVAP purge solenoid to 50 percent. If vacuum gauge indicates more than 10 in. H2O vacuum, go to DIAGNOSTIC AIDS . If vacuum gauge indicates less than 10 in. H2O vacuum, go to step  12.
  9. Monitor pressure gauge on EVAP pressure/purge diagnostic station. Disconnect EVAP purge pipe from EVAP canister. If EVAP system pressure decreases, go to step  14. If EVAP system pressure does not decrease, go to next step.
  10. Monitor pressure gauge on EVAP pressure/purge diagnostic station. Disconnect EVAP vapor line from EVAP canister. If EVAP system pressure decreases, go to step  17. If EVAP system pressure does not decrease, go to step  13.
  11. Monitor FTP sensor voltage on scan tool. If voltage is more than 4.3 volts, go to DTC P0453: FUEL TANK PRESSURE SENSOR CIRCUIT HIGH VOLTAGE . If voltage is less than 4.3 volts, go to step  15.
  12. Check vacuum source to EVAP purge solenoid for blockage, damage or disconnections. Repair as necessary. After repairs, go to step  18. If vacuum source is okay, go to step  16.
  13. Repair EVAP vapor pipe restriction. After repairs, go to step  18.
  14. Repair EVAP purge pipe restriction. After repairs, go to step  18.
  15. Replace FTP sensor. See REMOVAL, OVERHAUL & INSTALLATION - CARS article. After repairs, go to step  18.
  16. Repair EVAP purge solenoid. After repairs, go to step  18.
  17. Repair EVAP canister. See REMOVAL, OVERHAUL & INSTALLATION - CARS article. After repairs, go to next step.
  18. Turn ignition on. Using scan tool, command EVAP vent solenoid on. Pressurize system to 5 in. H2O using EVAP pressure/purge diagnostic station. Rotate EVAP pressure/purge diagnostic station rotary switch to OFF/HOLD position. Monitor pressure gage for 5 minutes. If scan tool indicates SERVICE BAY TEST PASSED, go to next step. If service bay test fails, go to step  7.
  19. While monitoring EVAP pressure/purge diagnostic station pressure gauge, command EVAP purge solenoid to 50 percent. If EVAP system pressure decreases, go to next step. If EVAP system pressure does not decrease, go to step  9.
  20. Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, go to applicable DTC test. See DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no undiagnosed DTCs are displayed, system is okay.
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