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Home >> Pontiac >> 2000 >> Firebird Base, 2D Convertible, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - Self-Diagnostics - 3.8L >> Diagnostic Tests >> DTC P1441: EVAP System Flow During Non-Purge >> Diagnostic Procedures

Diagnostic Procedures

  1. Perform On-Board Diagnostic (OBD) system check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK . After performing OBD system check, go to next step.
  2. Check for disconnected vacuum or purge lines. Check for loose or missing fuel fill cap. Check if DTC P0443 or P0449 is also set. Repair as necessary. If no problem is found, go to next step.
  3. Turn ignition off. Disconnect EVAP canister line from EVAP canister purge valve to relieve fuel tank pressure. Turn ignition on, with engine off. Using scan tool, observe FUEL TANK PRESSURE parameter. If scan tool indicates that this zero in. H2O go to next step. If scan tool does not indicate that this zero in. H2O, go to step  12.
  4. Zero pressure and vacuum gauges on EVAP Pressure/Purge Diagnostic Station (J-41413). Turn ignition off. Reconnect all EVAP hardware previously disconnected. Install Fill Tank Cap Adaptor (J-41415-40) to fuel filler neck and fuel fill cap. Connect EVAP diagnostic station to fuel tank cap adaptor. Turn ignition on, with engine off. Using scan tool, capture FAIL RECORDS data this DTC. Clear DTCs. Using scan tool, select SEAL option to seal EVAP system. Attempt to pressurize system to 5 in. H2O by slowly turning rotary switch to PRESSURE position. If 5 in. H2O pressure is achieved, go to next step. If pressure cannot be achieved, go to step  6.
  5. Maintain EVAP system pressure at 5 in. H2O. Using scan tool, read FUEL TANK PRESSURE. If scan tool indicates fuel tank pressure is about 5 in. H2O, see DIAGNOSTIC AIDS . If scan tool does not indicate that fuel tank pressure is 5 in. H2O, go to step  9.
  6. Check EVAP purge vacuum and source line routing and connections at EVAP purge solenoid. Repair as necessary. After repairs, go to step  12. If no problem is found, go to next step.
  7. Connect vacuum hose on EVAP diagnostic station to canister side of purge valve. Turn ignition on, with engine off. Using scan tool, select SEAL option to seal EVAP system. Start and operate engine at 1200-1500 RPM. Observe vacuum level. If vacuum is level is at zero in. Hg, see DIAGNOSTIC AIDS . If vacuum level is not zero in. Hg, go to next step.
  8. Replace EVAP purge valve. After replacing EVAP purge valve, go to step  12.
  9. Check for restricted fuel tank vapor and purge line. Repair as necessary. After repairs, go to step  12. If no problem is found, diagnose using appropriate DTC P0452 test. See DTC P0452: FUEL TANK PRESSURE SENSOR CIRCUIT LOW VOLTAGE (EXCEPT GRAND PRIX, IMPALA, MONTE CARLO & REGAL)  or DTC P0452: FUEL TANK PRESSURE SENSOR CIRCUIT LOW VOLTAGE (GRAND PRIX, IMPALA, MONTE CARLO & REGAL) .
  10. Repair kinked or restricted canister purge line between EVAP canister purge valve and EVAP canister. After repairs, go to step  12.
  11. Turn ignition off. Disconnect EVAP canister line from fuel tank or EVAP canister to relieve fuel tank pressure. Turn ignition on, with engine off. Using scan tool, observe fuel tank pressure parameter. If fuel tank pressure is about zero in. H2O, go to step  10. If fuel tank pressure is not about zero in. Hg, diagnose using appropriate DTC P0453 test. See DTC P0453: FUEL TANK PRESSURE SENSOR CIRCUIT HIGH VOLTAGE (EXCEPT GRAND PRIX, IMPALA, MONTE CARLO & REGAL)  or DTC P0453: FUEL TANK PRESSURE SENSOR CIRCUIT HIGH VOLTAGE (GRAND PRIX, IMPALA, MONTE CARLO & REGAL) .
  12. Reconnect all previously disconnected EVAP hardware. Turn ignition on, with engine off. Using scan tool, seal EVAP system. Using EVAP diagnostic station, pressurize system to 15 in. H2O. Observe pressure for 2 minutes. If pressure decreases to 10 in. H2O, go to step  3. If pressure does not decrease to 10 in. Hg, system is okay.
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