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Home › Chevrolet › 2000 › Tracker 4D Utility, 4WD, Standard › Repair and Diagnosis › Engine Performance › System › Engine Control System Self-Diagnostics › Diagnostic Tests › DTC P0440: Evaporative Emissions System › Diagnostic Procedures

Diagnostic Procedures

  1. Perform On-Board Diagnostic (OBD) system check. See ON-BOARD DIAGNOSTIC SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
  2. If any other EVAP DTCs are set except P0455, diagnose affected DTC(s). If no other EVAP DTCs are set, go to next step.
  3. Visually inspect entire EVAP control system for loose hose connections, damaged or deteriorated hoses, clogged hoses, missing or damaged components, poor harness connections, loose or faulty fuel filler cap. If problem(s) exists, go to step  21. If no problems exist, go to next step.
    4. WARNING: DO NOT breathe air through EVAP component tubes and hoses. Fuel vapors inside EVAP components may cause personal injury.
  4. Remove fuel tank pressure control valve. Blow air through valve from canister port (some resistance should be present). If air escapes from fuel tank port, go to next step. If air does not escape from fuel tank port, go to step  29.
    5. NOTE: Fuel tank pressure control valve will not allow air to flow from tank side port to canister side port until pressure on tank side port exceeds.5 psi (.04 kg/cm2 ).
  5. Blow hard through fuel tank port of fuel tank pressure control valve. Air should escape from canister port. Apply 15 in. Hg of vacuum to vacuum port of fuel tank pressure control valve. With vacuum applied, blow gently through fuel tank port. Air should escape easily through canister port. If fuel tank pressure control valve operates as described, go to next step. If fuel tank pressure control valve does not operate as described, go to step  29.
  6. Turn ignition on, with engine off. Using scan tool, command EVAP tank pressure control solenoid vacuum valve on. Disconnect vacuum hoses from EVAP tank pressure control solenoid vacuum valve. Blow air through fuel tank pressure control valve port of EVAP tank pressure control solenoid vacuum valve. If air escapes from vacuum port, go to next step. If air does not escape from vacuum port, go to step  8.
  7. Check vacuum hoses and intake manifold port for leaks, cracks or blockage. Repair as necessary. After repairs, go to step  35. If vacuum hoses and intake manifold port are okay, go to step  10.
  8. Turn ignition off. Disconnect EVAP tank pressure control solenoid vacuum valve harness connector. Turn ignition on, with engine off. Using a test light connected to ground, probe EVAP tank pressure control solenoid vacuum valve harness connector terminal No. 1 (ignition positive voltage circuit). If test light illuminates, go to next step. If test light does not illuminate, go to step  23.
  9. Using a test light connected to battery voltage, probe EVAP tank pressure control solenoid vacuum valve harness connector terminal No. 2 (control circuit). Using scan tool, command EVAP tank pressure control solenoid vacuum valve on and off, while observing test light. Test light should illuminate when EVAP pressure control solenoid vacuum valve is on, and should not illuminate when off. If test light illuminates as described, go to step  33. If test light does not illuminate as described, go to step  32.
  10. Check EVAP canister purge valve for the following conditions:
    • No manifold vacuum at intake manifold vacuum port.
    • Leaking or damaged vacuum hoses.
    • Clogged or restricted vacuum hoses or passages.
    Repair as necessary. After repairs, go to step  35. If no problem exists, go to next step.
  11. Turn ignition on, with engine off. Disconnect EVAP canister purge valve vacuum hoses from intake manifold and EVAP canister. Blow air into vacuum hose that was disconnected from EVAP canister. Air should not escape from disconnected intake manifold vacuum hose. Using scan tool, command EVAP canister purge valve on and adjust duty cycle to 100 percent. Blow air into vacuum hose that was disconnected from EVAP canister. Air should now escape from disconnected intake manifold vacuum hose. If EVAP canister purge valve operated as described, go to step  14. If EVAP canister purge valve does not operated as described, go to next step.
  12. Turn ignition on, with engine off. Using a test light connected to ground, probe EVAP canister purge valve harness connector terminal No. 1 (ignition positive voltage circuit). If test light illuminates, go to next step. If test light does not illuminate, go to step  23.
  13. Using a test light connected to battery voltage, probe EVAP canister purge valve harness connector terminal No. 2 (control circuit). Using scan tool, command EVAP canister purge valve on and adjust duty cycle from zero to 100 percent, while observing test light. If test light flashes, and then illuminates steady when 100 percent duty cycle is reached, go to step  31. If test light does not flash, and then illuminate steady when 100 percent duty cycle is reached, go to step  30.
  14. Turn ignition off. Remove EVAP canister vacuum hose from EVAP canister vent solenoid. Apply 15 in. Hg of vacuum to EVAP canister side of EVAP canister vent solenoid. If solenoid holds vacuum, go to step  27. If solenoid does not hold vacuum, go to next step.
  15. Turn ignition on, with engine off. Using scan tool, command EVAP canister vent solenoid on. Apply 15 in. Hg of vacuum to EVAP canister side of EVAP canister vent solenoid. If solenoid holds vacuum, go to next step. If solenoid does not hold vacuum, go to step  17.
  16. With vacuum still applied, use scan tool to command EVAP canister vent solenoid off. If vacuum is released, go to step  19. If vacuum is not released, go to step  24.
  17. Turn ignition off. Disconnect EVAP canister vent solenoid harness connector. Turn ignition on, with engine off. Using a test light connected to ground, probe EVAP canister vent solenoid harness connector terminal No. 1 (ignition positive voltage circuit). If test light illuminates, go to next step. If test light does not illuminate, go to step  23.
  18. Using scan tool, command EVAP canister vent solenoid on. Using a test light connected to battery voltage, probe EVAP canister vent solenoid harness connector terminal No. 2 (control circuit). If test light illuminates, go to step  28. If test light does not illuminate, go to step  26.
  19. Turn ignition on, with engine off. Remove fuel filler cap and install Gas Cap Adapter (J41415-30). Connect Pressure/Purge Diagnostic Station (J41413-EVAP) to gas cap adapter. Apply 15 in. Hg of vacuum to EVAP tank pressure control valve vacuum port. Using scan tool, command EVAP canister vent solenoid on. Using EVAP pressure/purge diagnostic station, pressurize fuel tank to 15 in. H2 O (28 mm Hg). Turn rotary switch on EVAP pressure/purge diagnostic station to HOLD position and observe EVAP pressure gauge. If EVAP pressure gauge decreases to 10 in. H2 O (18.6 mm Hg) or less within 2 minutes, go to next step. If EVAP pressure gauge does not decrease to 10 in. H2 O (18.6 mm Hg) or less within 2 minutes, go to step  22.
  20. With condition met in previous step, continue to pressurize fuel tank to 30 in. H2 O (56 mm Hg). With tank pressurized, check EVAP system for leaks using Ultrasonic Leak Detector (J-41416). If leaks exist, go to next step. If no leaks exist, go to step  22.
  21. Repair leaks and/or replace any faulty components as necessary. After repairs, go to step  35.
  22. Disconnect vacuum hoses from EVAP canister and plug EVAP canister vent solenoid port. Connect vacuum pump to EVAP canister tank port. Attempt to obtain 10 in. H2 O (18.6 mm Hg) of vacuum. If EVAP canister holds vacuum, go to step  25. If EVAP canister does not hold vacuum, go to DIAGNOSTIC AIDS .
  23. Repair open in ignition positive voltage circuit between main relay and EVAP component. After repairs, go to step  35.
  24. Check for short to ground in control circuit between PCM and EVAP canister vent solenoid. Repair as necessary. After repairs, go to step  35. If circuit is okay, go to step  34.
  25. Replace EVAP canister. After replacing canister, go to step  35.
  26. Check for an open in control circuit between PCM and EVAP canister vent solenoid. Repair as necessary. After repairs, go to step  35. If circuit is okay, go to step  34.
  27. Check EVAP canister vent solenoid vacuum hoses for restriction. Repair as necessary. After repairs, go to step  35. If vacuum hoses are okay, go to next step.
  28. Replace EVAP canister vent solenoid. After replacing solenoid, go to step  35.
  29. Replace fuel tank pressure control valve. After replacing fuel tank pressure control valve, go to step  35.
  30. Check for an open or short in control circuit between PCM and EVAP canister purge valve. Repair as necessary. After repairs, go to step  35. If circuit is okay, go to step  34.
  31. Replace EVAP canister purge valve. After replacing canister purge valve, go to step  35.
  32. Check for an open or short in control circuit between PCM and EVAP tank pressure control solenoid vacuum valve. Repair as necessary. After repairs, go to step  35. If circuit is okay, go to step  34.
  33. Replace EVAP tank pressure control solenoid vacuum valve. After replacing solenoid vacuum valve, go to step  35.
  34. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
  35. After repairs, clear DTCs. Operate vehicle within FREEZE FRAME conditions that set DTC. Check for DTCs. If no DTCs are stored, repair is complete. If any DTCs are stored, diagnose DTC(s).
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