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Home >> GMC >> 2003 >> Safari Van Cargo, AWD >> Repair and Diagnosis >> Engine Performance >> Testing & Diagnosis >> Engine Controls - Self-Diagnostics - 4.3L >> Diagnostic Tests >> DTC P0443: EVAP Purge Solenoid Control Circuit >> Diagnostic Procedures

Diagnostic Procedures

  1. Did you perform the Diagnostic System Check - Engine Controls? If yes, go to next step. If no, see DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS  under SELF-DIAGNOSTIC SYSTEM.
  2. Start and idle the engine. Command the vent valve ON, closed, with a scan tool. Monitor the Fuel Tank Pressure (FTP) sensor value with the scan tool. Command the purge valve to 50 percent. Does the FTP value on the scan tool change? If yes, go to next step. If no, go to step  4.
  3. Observe the Freeze Frame/Failure Records for this DTC. Turn ignition off for 30 seconds. Start engine. Operate the vehicle within the Conditions for Running DTC. See CONDITIONS FOR RUNNING DTC . You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition cycle? If yes, go to next step. If no, see INTERMITTENTS in TROUBLE SHOOTING - NO CODES - 4.3L ASTRO, BLAZER, JIMMY CANADIAN, SAFARI, SONOMA & S10 PICKUP article.
  4. Turn ignition off. Disconnect the EVAP purge valve harness connector. Turn ignition on, with engine off. Probe the ignition 1 voltage circuit at the EVAP purge valve harness connector with a test light connected to a good ground. Does the test light illuminate? If yes, go to next step. If no, go to step  11.
  5. Connect a test light between the control circuit and the ignition voltage circuit of the EVAP purge valve harness connector. Command the EVAP purge valve to zero percent with a scan tool. Is the test light illuminated? If yes, go to step  8. If no, go to next step.
  6. Command the EVAP purge valve to 50 percent with a scan tool. Does the test light illuminate or pulse when the EVAP purge valve is commanded to 50 percent? If yes, go to step  9. If no, go to next step.
  7. Test the control circuit of the EVAP purge valve for an open or short to voltage. Did you find and correct the condition? If yes, go to step  14. If no, go to step  10.
  8. Test the control circuit of the EVAP purge valve for a short to ground. Did you find and correct the condition? If yes, go to step  14. If no, go to step  13.
  9. Inspect for poor connections at the harness connector of the EVAP purge valve. Did you find and correct the condition? If yes, go to step  14. If no, go to step  12.
  10. Inspect for poor connections at the harness connector of the control module. Did you find and correct the condition? If yes, go to step  14. If no, go to step  13.
  11. Repair ignition voltage circuit of the EVAP purge valve for an open or a short to ground. Replace the fuse if necessary. After repairs, go to step  14.
  12. Replace EVAP purge valve. After repairs, go to step  14.
  13. Replace PCM. See appropriate REMOVAL & INSTALLATION article. Reprogram PCM. See POWERTRAIN CONTROL MODULE  under PROGRAMMING. After repairs, go to next step.
  14. Clear the DTCs with a scan tool. Turn ignition off for 30 seconds. Start engine. Operate the vehicle within the Conditions for Running DTC. See CONDITIONS FOR RUNNING DTC . Does the DTC run and pass? If yes, go to next step. If no, go to step  2.
  15. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, system is okay.
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