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Home >> Buick >> 1996 >> Century Custom >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - Tests W/Codes - 3.1L >> Diagnostic Trouble Codes >> 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. Turn ignition on, with engine off. Using scan tool, select ENG 1 data list. Observe EVAP VACUUM SW display. If reading indicates no purge, go to next step. If reading does not indicate closed, go to DTC P1442. Diagnose DTC as necessary.
  3. Start engine and allow it to idle. Observe EVAP VACUUM SW display and command EVAP purge solenoid off. If reading indicates no purge, go to next step. If reading does not indicate no purge, go to step 5).
  4. Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME data and note parameters. Start engine and operate vehicle as close to conditions recorded in FREEZE FRAME as possible. Monitor SPECIFIC DTC info for DTC P1441 until DTC P1441 test runs. If scan tool indicates FAILED THIS IGN, go to next step. If scan tool does not indicate FAILED THIS IGN, see DIAGNOSTIC AIDS.
  5. Disconnect EVAP purge solenoid connector. Start engine and allow it to idle. Observe EVAP VACUUM SW display. If reading indicates no purge, go to next step. If reading does not indicate no purge, go to step 7).
  6. Turn ignition off. Disconnect PCM connector. Check for short to ground in EVAP canister purge driver (control) circuit. Repair as necessary. After repair is completed, go to step 12). If circuit is okay, go to step 8).
  7. Disconnect vacuum signal hose from EVAP purge vacuum switch. Connect a vacuum gauge to vacuum signal hose. Start engine and allow it to idle. If vacuum is more than 12 in. Hg, go to step 9). If vacuum is 12 in. Hg or less, go to step 11).
  8. Replace PCM. Reprogram replacement PCM. After repair is completed, go to step 12).
  9. Check for incorrect vacuum hose routing or switched vacuum hoses at EVAP purge solenoid. Repair as necessary. After repair is completed, go to step 12). If vacuum hoses are okay, go to next step.
  10. Replace EVAP purge solenoid. Repair as necessary. After repair is completed, go to step 12).
  11. Replace EVAP vacuum switch. Repair as necessary. After repair is completed, go to next step.
  12. Using scan tool, select CLEAR INFO or CLEAR DTCS function to clear DTCs. Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME data and note parameters. Start engine and operate vehicle within conditions required for setting this DTC, and as close to conditions recorded in FREEZE FRAME as possible. Monitor SPECIFIC DTC info for DTC P1441 until DTC P1441 test runs. If scan tool indicates FAILED THIS IGN, repeat step 2). If scan tool does not indicate FAILED THIS IGN, repair is complete.
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