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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 100 (Engine Control System Self-Diagnostics - 3.8L) >> Diagnostic Tests >> DTC P0443: EVAP Purge Solenoid Control Circuit >> Diagnostic Procedures

Diagnostic Procedures

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  1. Perform Diagnostic System Check - Engine Controls. See DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS  under SELF-DIAGNOSTIC SYSTEM. After performing Diagnostic System Check - Engine Controls, go to next step.
  2. Turn ignition on, engine off. Using scan tool, command EVAP purge valve to 50 percent, and then to zero percent. Does the EVAP purge valve respond to the commanded state? If yes, go to next step. If no, go to step  4.
  3. Observe FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Start engine. Operate vehicle within Conditions for Running DTC or as close to FREEZE FRAME/FAILURE RECORDS data as possible. Does the DTC fail this ignition cycle? If yes, go to next step. If no, see INTERMITTENT CONDITIONS  under SELF-DIAGNOSTIC SYSTEM.
  4. Turn ignition off. Disconnect EVAP purge valve connector. Turn ignition on, engine off. Probe the ignition voltage circuit at the EVAP purge valve harness connector with a test lamp connected to a good ground. Does the test lamp illuminate? If yes, go to next step. If no, go to step  11.
  5. Connect a test lamp between the control circuit and the ignition voltage circuit of the EVAP purge valve harness connector. With a scan tool, command the EVAP purge valve to 0 percent. Does the test lamp illuminate? If yes, go to step  8. If no, go to next step.
  6. With a scan tool, command the EVAP purge valve to 50 percent. Does the test lamp 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 the ignition voltage circuit of the EVAP purge valve. After repairs, go to step  14.
  12. Replace EVAP purge valve. After repairs, go to step  14.
  13. Replace PCM. Program replacement PCM. See POWERTRAIN CONTROL MODULE  under PROGRAMMING. After repairs, go to next step.
  14. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within Conditions for Running DTC. Does DTC run and pass? If yes, go to next step. If no, go to step  2.
  15. Using scan tool, observe stored information. Does scan tool displays any DTCs that have not been diagnosed? If yes, see DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, system is okay.
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