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Home >> Cadillac >> 1996 >> Eldorado Base >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - Tests W/Codes >> Diagnostic Trouble Codes >> DTC P1441 - EVAP System Flow During Non-Purge >> Diagnostic Procedures
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Diagnostic Procedures

  1. Perform Powertrain On-Board Diagnostic (OBD) System Check. After performing OBD system check, go to next step.
  2. Turn ignition on. Using scan tool, check if DTC P1645 is also present. If DTC P1645 is present, diagnose DTC first. If DTC P1645 is not present, go to next step.
  3. Turn ignition off. Remove fuel cap for about 10 seconds. Replace fuel cap. Turn ignition on, with engine off. Using scan tool, select ENGINE 2 and note EVAP VACUUM SW display. If scan tool displays PURGING, go to step 9). If scan tool does not display PURGING, go to next step.
  4. While observing EVAP VACUUM SWITCH display, start and idle engine. If scan tool displays PURGING, go to next step. If scan tool does not display PURGING, fault is not present. See DIAGNOSTIC AIDS.
  5. Note EVAP PURGE SOL display. If scan tool shows duty cycle less than 9.8%, go to step 7). If scan tool shows duty cycle at greater than 9.8%, go to next step.
  6. Select MISC TESTS, then OUTPUT TESTS, then EVAP PURGE. Command EVAP purge solenoid OFF (0%). Note EVAP VACUUM SW display. If scan tool displays PURGING, go to next step. If scan toll does not display PURGING, fault is not present. See DIAGNOSTIC AIDS.
  7. Check all vacuum lines for proper routing. Repair as necessary. If vacuum line routings are okay, go to next step.
  8. Replace EVAP solenoid.
  9. Disconnect EVAP vacuum switch. Using jumper wire, jumper EVAP vacuum switch harness connector terminals. If scan tool display shows NO FLOW, go to step 12). If scan tool display does not show NO FLOW, go to next step.
  10. Using DVOM, check voltage between ground and EVAP vacuum switch input signal circuit at harness connector terminal. If voltage reading is 10.5 volts or less, go to step 13). If voltage reading is greater than 10.5 volts, go to next step.
  11. Store fluid life index as indicated on scan tool. Turn ignition off and wait 30 seconds, then disconnect PCM harness connector C2. Using DVOM, check resistance of EVAP vacuum switch input circuit between PCM harness connector and EVAP vacuum switch harness connector terminals. If resistance is 5 ohms or less, go to step 15). If resistance is greater than 5 ohms, go to step 14).
  12. Replace EVAP vacuum switch.
  13. Repair open in ground circuit between EVAP vacuum switch and ground.
  14. Repair open in EVAP vacuum switch input circuit between switch and PCM harness connector terminal.
  15. Check EVAP vacuum switch input circuit terminal contact at PCM harness connector. Repair as necessary. If terminal contact is okay, go to next step.
  16. Replace PCM.
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