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Home >> Pontiac >> 2000 >> Firebird Base, 2D Convertible, Automatic >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 1 (Engine Control System Self-Diagnostics - 5.7L) >> Diagnostic Tests >> DTC P0404: EGR Open Position Performance ("F" Body) >> Diagnostic Procedures
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Diagnostic Procedures

WARNING: This page is about a different variant/trim than selected.
  1. Perform On-Board Diagnostic (OBD) system check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
  2. Start and operate engine at idle. Using scan tool, command EGR valve to 50 percent. If engine runs rough or stalls, go to next step. If engine does not run rough or stall, go to step  6.
  3. Using scan tool, command EGR valve to 50 percent. Check if actual EGR position is within specified range. If EGR position is 48-52 percent, see DIAGNOSTIC AIDS . If actual EGR position is not within 48-52 percent, go to next step.
  4. Turn ignition off. Disconnect PCM and EGR harness connector. Check resistance of EGR valve control circuit. If resistance is 0-2 ohms, go to next step. If resistance is not 0-2 ohms, go to step  14.
  5. Check resistance of EGR valve ground circuit. If resistance is 0-2 ohms, go to step  16. If resistance is not 0-2 ohms, go to step  15.
  6. Turn ignition off. Disconnect EGR valve harness connector. Turn ignition on, command EGR to 100 percent. Using a test light connected to ground, probe EGR control circuit. If test light illuminates, go to next step. If test light does not illuminate, go to step  8.
  7. Using a test light connected to battery voltage, probe EGR valve ground circuit. If test light illuminates, go to step  16. If test light does not illuminate, go to step  11.
  8. Turn ignition off. Disconnect PCM harness connector. Check continuity of EGR valve control circuit. If continuity exists, go to next step. If continuity does not exist, go to step  12.
  9. Check continuity of EGR valve control circuit. If continuity exists, go to step  12. If continuity does not exist, go to next step.
  10. Check continuity from EGR control circuit to all other circuits in PCM harness connector. If continuity exists, go to step  12. If continuity does not exist, go to step  18.
  11. Turn ignition off. Disconnect PCM harness connector. Check continuity of EGR valve ground circuit. If continuity exists, go to step  18. If continuity does not exist, go to step  13.
  12. Repair open, short to ground or short to each other in EGR control circuit. After repairs, go to step  20.
  13. Repair open in EGR ground circuit. After repairs, go to step  20
  14. Repair high resistance in EGR valve control circuit. After repairs, go to step  20
  15. Repair high resistance in EGR valve ground circuit. After repairs, go to step  20
  16. Check terminal contact at EGR valve harness connector. Repair as necessary. After repairs, go to step  20. If contacts are okay, go to next step.
  17. Replace EGR valve. After replacing EGR valve, go to step  20.
  18. Check for poor connection or proper terminal contact at PCM. Repair as necessary. After repairs, go to step  20. If connections or terminal contact is okay, go to next step.
  19. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
  20. Using scan tool, select DTC, CLEAR INFO function. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter this DTC. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool did not indicate that this test ran and passed, repeat step  2.
  21. Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, go to applicable DTC test.
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