LEMON Manuals: Even more car manuals for everyone
Home >> GMC >> 1997 >> Forward Control 4.3 W, L35, Automatic >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 11 (Engine Controls - Tests W/Codes - 7.4L (P Series)) >> Diagnostic Trouble Codes >> DTC P1441 - EVAP Emission System Flow During Non-Purge >> Diagnostic Procedures

Diagnostic Procedures

WARNING: This page is about a different variant/trim than selected.
  1. Perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK. See the F - BASIC TESTING - 7.4L article. After performing OBD system check, go to next step.
  2. If DTC P0107 is also set, diagnose that DTC first. If DTC P0107 is not set, turn ignition on with engine off. Using scan tool, command EVAP canister purge solenoid valve on and off. If valve clicks when commanded on and off, go to step 5). If valve does not click when commanded on and off, go to next step.
  3. Unplug EVAP solenoid valve connector. Connect test light between connector terminals. Command solenoid on and off with scan tool. If test light turns on and off, go to next step. If test light does not turn on and off, go to step 15).
  4. Replace EVAP solenoid. After repairs, go to step 16).
  5. With ignition on and engine off, check scan tool EVAP duty cycle. If duty cycle is zero percent, see DIAGNOSTIC AIDS. If duty cycle is not zero percent, go to next step.
  6. Unplug EVAP vacuum switch connector. Monitor scan tool. If scan tool displays PURGE, go to next step. If scan tool does not display PURGE, go to step 11).
  7. Connect jumper wire between EVAP vacuum switch connector terminals. If scan tool reads NO PURGE, go to next step. If scan tool does not read NO PURGE, go to step 11).
  8. Check sensor connections. If a problem is found, go to next step. If problem is not found, go to step 10).
  9. Repair sensor connections. After repairs, go to step 16).
  10. Replace sensor. After replacing sensor, go to step 16).
  11. With DVOM to ground, check voltage on EVAP vacuum switch signal circuit terminal. If voltage is about 12 volts, go to next step. If voltage is not about 12 volts, go to step 14).
  12. Check for open ground circuit and/or faulty connection. If a problem exists, go to next step. If no problem exists, go to step 15).
  13. Repair ground circuit as necessary. After repairs, go to step 16).
  14. Repair open in 12-volt signal circuit. After repairs, go to step 16).
  15. Replace VCM. Program replacement VCM using required equipment. After replacing VCM, go to next step.
  16. Using a scan tool, select DTC, CLEAR INFO. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter DTC P1441. Operate vehicle within the conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, repeat step 2).
  17. Using scan tool, select CAPTURE INFO, REVIEW INFO. If any undiagnosed DTC(s) are displayed, go to applicable DTC test.
scientia non olet · About LEMON Manuals