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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 P1441: EVAP System Flow During Non-Purge >> Diagnostic Procedure
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Diagnostic Procedure

  1. Perform On-Board Diagnostic (OBD) System Check. See BASIC DIAGNOSTIC PROCEDURES article. After performing OBD system check, go to next step.
  2. Remove fuel cap. Turn ignition on. Using scan tool, observe FUEL TANK PRESSURE. If scan tool display reads 1.51 volts, go to next step. If scan tool display is not as specified, go to DTC P0452: FUEL TANK PRESSURE (FTP) SENSOR LOW VOLTAGE  or DTC P0453: FUEL TANK PRESSURE SENSOR HIGH VOLTAGE  .
  3. Zero pressure and vacuum gauges on EVAP Pressure/Purge Cart (J41413). Reinstall fuel cap. Using scan tool, command EVAP vent solenoid ON (closed). Disconnect EVAP canister hose that comes from EVAP purge solenoid valve. Connect EVAP pressure/purge cart to EVAP service port. Using EVAP pressure/purge cart, attempt to pressurize EVAP system until scan tool FUEL TANK PRESSURE reads 1.52-1.60 volts. If specified pressure is not achieved, go to step  6. If specified pressure is achieved, go to next step.
  4. Disconnect EVAP pressure/purge cart from EVAP service port. Disconnect vacuum source line at engine for EVAP purge solenoid. Connect a vacuum pump to EVAP canister purge valve vacuum source fitting. Apply 15 in. H2 O vacuum. If scan tool FUEL TANK PRESSURE display reads 1.47-1.51 volts and holds steady, go to step  6. If scan tool reading is not as specified, go to next step.
  5. Replace EVAP purge solenoid valve. Retest system.
  6. Check for leaks, kinked or pinched hoses at EVAP system. Ensure that all hoses are routed correctly. Check for leak from vent solenoid valve, and also ensure that filter located near vent solenoid is not plugged. Repair as necessary and retest system. If no problem was found, go to next step.
  7. Start engine. Remove fuel cap. Using scan tool, command EVAP vent solenoid ON (closed) and EVAP purge solenoid OFF (0 percent). Reinstall fuel cap. Monitor scan tool FUEL TANK VACUUM display while holding engine speed at 2500 RPM. If scan tool display reads 30-40 percent when vent solenoid valve is ON, and 0 percent when purge solenoid valve is OFF, repair is complete. If scan tool display is not as specified, go to DIAGNOSTIC AIDS .
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