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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 103 (Engine Controls Self-Diagnostics - 2.2L) >> Diagnostic Tests >> DTC P0440: EVAP System >> Diagnostic Procedures

Diagnostic Procedures

WARNING: This page is about a different car, the 2002 Pontiac Sunfire, 2002 Pontiac Grand Am, 2002 Oldsmobile Alero, and 2002 Chevrolet Cavalier. 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. Are DTCs P0446, P0452, P0453 or P1441 also set? If yes, see DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, go to next step.
  3. Inspect the EVAP system for a loose, missing, or damaged service port Schrader valve. A loose, incorrect, missing, or damaged fuel fill cap. A damaged EVAP canister purge valve. Raise vehicle on a hoist and inspect the EVAP system for disconnected, improperly routed, kinked or damaged EVAP pipes and hoses, damaged EVAP canister vent valve or EVAP canister. Did you find and correct the condition? If yes, go to step  33. If no, go to next step.
  4. Use the scan tool in order to clear the DTCs. Command the EVAP canister purge valve to 50 percent and back to 0 percent with the scan tool. Do you hear or feel a clicking from the EVAP purge valve when it is commanded to 50 percent? If yes, go to next step. If no, go to step  6.
  5. Command the EVAP canister vent valve ON and OFF with the scan tool. Do you hear or feel a click as the EVAP vent valve is commanded ON and OFF? If yes, go to step  10. If no, go to step  8.
  6. Disconnect EVAP canister purge valve harness connector. Turn ignition on, with engine off. Connect a test light between the ignition voltage circuit of the EVAP canister purge valve and a known-good ground. Does the test light illuminate? If yes, go to next step. If no, go to step  24.
  7. Connect a test light between the ignition voltage circuit and the control circuit of the EVAP purge valve. Command the EVAP canister purge valve to 50 percent and then to 0 percent with a scan tool. Does the test light illuminate or pulsate when the EVAP purge valve is commanded to 50 percent and turn OFF when the EVAP canister purge valve is commanded to 0 percent? If yes, go to step  19. If no, go to step  17.
  8. Turn ignition on, with engine off. Disconnect EVAP vent valve harness connector. Connect a test light between the EVAP canister vent valve ignition voltage circuit and a good ground. Does the test light illuminate? If yes, go to next step. If no, go to step  25.
  9. Connect the test light between the ignition voltage circuit and the control circuit of the EVAP canister vent valve. Command the EVAP canister vent valve ON, with a scan tool. Does the test light illuminate when the EVAP canister vent valve is commanded ON? If yes, go to step  20. If no, go to step  18.
  10. Turn ignition off. Disconnect EVAP purge pipe from the EVAP canister purge valve. Connect a vacuum gauge directly to the EVAP purge connection of the EVAP canister purge valve. Start engine. Increase the engine speed to 1500 RPM. Command the EVAP canister purge valve to 50 percent with a scan tool. Is the vacuum at or more than 15 in. H2O? If yes, go to next step. If no, go to step  23.
    11. NOTE: Always zero the EVAP pressure and vacuum (in. H2O) gauges on the J-41413 EVAP Pressure/Purge Diagnostic Station before proceeding with diagnosis.
  11. Reconnect the EVAP purge pipe to the EVAP canister purge valve. Install the J-41415-40 Fuel Tank Cap Adaptor. Connect the J-41413 and vehicle fuel fill cap to the J-41415-40. Turn ignition on, with engine off. Use a scan tool in order to seal the EVAP system. Using the J-41413, attempt to pressurize the EVAP system to the specified value. Rotate the J-41413 rotary switch to the OFF/HOLD position. Were you able to obtain and hold the 5 in. H2O for 1 minute? If yes, go to next step. If no, go to step  13.
  12. Compare the J-41413 pressure gauge value to the scan tool FTP sensor value. Does the EVAP pressure/purge diagnostic station gauge value correspond to the FTP sensor value on the scan tool ? If yes, go to step  14. If no, go to step  16.
  13. With the J-41413 Ultrasonic Leak Detector, continuously attempt to pressurize the EVAP system. Important: Partially lowering the fuel tank may be necessary to inspect components located in the upper portion of the tank. With the J-41416, inspect for leaks in the EVAP system purge pipe, EVAP vapor pipe, EVAP vent hose/pipe, fuel fill pipe/hose and fuel fill cap. The EVAP canister, canister vent valve, canister purge valve, fuel sender assembly and/or seal, FTP sensor seal, fill limiter vent valve, pressure relief valve, rollover valves, and fuel tank. Did you find and repair the condition? If yes, go to step  33. If no, go to DIAGNOSTIC AIDS .
  14. Monitor the J-41413 pressure gauge. Disconnect EVAP purge pipe from the EVAP Canister. Does the EVAP pressure/purge diagnostic station gauge decrease to about 0 in. H2O? If yes, go to step  26. If no, go to next step.
  15. Observe the pressure gauge on the EVAP diagnostic station. Disconnect EVAP vapor pipe from the EVAP Canister. Does the EVAP pressure/purge diagnostic station gauge decrease to about 0 in. H2O? If yes, go to step  30. If no, go to step  27.
  16. Is the FTP sensor value more than 4.3 volts? If yes, go to DTC P0453: FUEL TANK PRESSURE SENSOR CIRCUIT - HIGH VOLTAGE . If no, go to step  21.
  17. Test the control circuit of the EVAP canister purge valve for an open or short to voltage. Did you find and correct the condition? If yes, go to step  33. If no, go to step  22.
  18. Test the control circuit of the EVAP canister vent valve for an open or short to voltage. Did you find and correct the condition? If yes, go to step  33. If no, go to step  22.
  19. Test for poor connections at the harness connector of the EVAP canister purge valve. Did you find and correct the condition? If yes, go to step  33. If no, go to step  28.
  20. Test for poor connections at the harness connector of the EVAP canister vent valve. Did you find and correct the condition? If yes, go to step  33. If no, go to step  29.
  21. Test for poor connections at the harness connector of the FTP. Did you find and correct the condition? If yes, go to step  33. If no, go to step  31.
  22. Test for poor connections at the harness connector of the control module. Did you find and correct the condition? If yes, go to step  33. If no, go to step  32.
  23. Inspect the vacuum source to the EVAP purge valve for blockage, cuts, or disconnects. Repair as necessary. Did you find and correct the condition? If yes, go to step  33. If no, go to step  28.
  24. Repair ignition voltage circuit of the EVAP purge valve for an open or short to ground. Replace fuse as necessary. After repairs, go to step  33.
  25. Repair ignition voltage circuit of the EVAP vent valve for an open or short to ground. Replace fuse as necessary. After repairs, go to step  33.
  26. Repair restriction in the EVAP purge pipe. After repairs, go to step  33.
  27. Repair restriction in the EVAP vapor pipe. After repairs, go to step  33.
  28. Replace EVAP canister purge valve. After repairs, go to step  33.
  29. Replace EVAP canister vent valve. When complete, go to step  33.
  30. Replace EVAP canister. When complete, go to step  33.
  31. Replace FTP sensor. When complete go to step  33.
  32. Replace PCM. See POWERTRAIN CONTROL MODULE in appropriate REMOVAL, OVERHAUL & INSTALLATION article. Perform PCM relearn procedure. See POWERTRAIN CONTROL MODULE REPROGRAMMING  under PROGRAMMING. After replacing PCM, go to next step.
  33. Turn ignition on, with engine off. Command the EVAP vent valve ON with a scan tool. Pressurize the EVAP system to the specified value with the J-41413. Place control knob on J-41413 to the OFF/HOLD position. Monitor the EVAP system pressure on the J-41413 for 5 minutes. Does the EVAP system pressure remain constant? If yes, go to next step. If no, go to step  4.
  34. With a scan tool, observe the stored information, 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.
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