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Home >> Isuzu >> 2000 >> Trooper S, 4WD, Part Time >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics - 3.2L & 3.5L >> Diagnostic Trouble Code Identification >> DTC P0440: EVAP System (Except VEHICROSS) >> Diagnostic Procedure
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Diagnostic Procedure

  1. Perform On-Board Diagnostic (OBD) System Check. See BASIC DIAGNOSTIC PROCEDURES article. Read and record FREEZE FRAME and/or FAIL RECORDS data for each DTC set. Go to next step.
  2. Check for DTC P0452 or P0453. If present, diagnose other DTCs before proceeding. If no other DTCs are set, go to next step.
  3. Turn ignition off. Remove fuel cap. Turn ignition on. Using scan tool, read FUEL TANK PRESSURE. If scan tool displays 1.51 volts, go to next step. If scan tool display is not as specified, go to DTC P0452: FUEL TANK PRESSURE SENSOR LOW VOLTAGE  or DTC P0453: FUEL TANK PRESSURE SENSOR HIGH VOLTAGE  .
  4. Reinstall fuel cap. Start engine and use scan tool to read FUEL TANK PRESSURE. If scan tool does not display 1.47-1.51 volts, go to step  6. If scan tool display is as specified, go to step  7.
  5. Disconnect fuel tank vapor and EVAP purge lines from EVAP canister. Plug fuel tank vapor line fitting at EVAP canister. Connect a hand vacuum pump to EVAP purge line fitting at EVAP canister. Ensure EVAP vent solenoid is still commanded ON (closed). Attempt to apply vacuum to EVAP canister until FUEL TANK PRESSURE reads 1.47-1.51 volts. If FUEL TANK PRESSURE reading is maintained as specified, go to step  8. If FUEL TANK PRESSURE reading can not be maintained as specified, go to step  7.
  6. Check fuel tank vapor line and EVAP purge line for restriction. If restriction is found, repair as necessary and retest system. If no restriction is found, go to DTC P0452: FUEL TANK PRESSURE SENSOR LOW VOLTAGE  or DTC P0453: FUEL TANK PRESSURE SENSOR HIGH VOLTAGE  .
  7. Check if vent hose is disconnected or damaged. Check EVAP canister for damage. If a problem is found, repair as necessary retest system. If no problem is found, go to step  11.
  8. Check for missing or faulty fuel cap. Check for disconnected or leaking fuel tank vapor line. Check for disconnected or damaged EVAP purge line. If a problem is found, repair as necessary and retest system. If no problem is found, go to next step.
  9. Replace EVAP canister purge solenoid. Retest system.
  10. Locate and repair cause of no source vacuum to EVAP purge solenoid. Retest system.
  11. Replace EVAP canister vent solenoid. Retest system.
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