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Home >> Isuzu >> 2000 >> Rodeo LSE, 2.2 D >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics - 2.2L >> Diagnostic Trouble Code Identification >> DTC P0404: EGR Circuit Range/Performance >> Diagnostic Procedures

Diagnostic Procedures

  1. Perform On-Board Diagnostic II (OBD-II) system check. See SELF-DIAGNOSTICS - INTRODUCTION article. Go to next step.
  2. Turn ignition on. Command EGR valve percentage to 25, 50, 75 and 100, while observing EGR valve position. If actual EGR valve position follows the desired EGR position, go to step  19. If EGR actual position is different than EGR desired position, go to next step.
  3. Turn ignition off. Disconnect EGR valve harness connector. Turn ignition on. Using a test light connected to battery voltage, probe EGR ground circuit. If test light illuminates, go to next step. If test light does not illuminate, go to step  5.
  4. Using a test light connected to ground, probe EGR control circuit. Using scan tool, command EGR valve percentage to increase to 25, 50, 75 and 100. If test light illuminates brighter, flashes or maintains a steady glow with each increase command, go to step  6. If test light does not illuminate brighter, flash or maintain a steady glow for each increase command, go to step  7.
  5. Repair open or poor connection in EGR ground circuit as necessary. Go to step  19.
  6. Using test light connected to ground, probe EGR signal circuit. If test light illuminates, go to step  8. If test light does not illuminate, go to step  9.
  7. Using test light connected to ground, probe EGR control circuit. If test light illuminates, go to step  10. If test light does not illuminate, go to step  11.
  8. Check EGR signal circuit for short to voltage. Repair as necessary. Go to step  19. If short to voltage does not exist, go to step  12.
  9. Using a DVOM connected to ground, probe EGR 5-volt reference circuit terminal. If reading is about 5 volts, go to step  13. If reading is not about 5 volts, go to step  14.
  10. Check EGR control circuit for short to voltage. Repair as necessary. Go to step  19. If short to voltage does not exist, go to step  12.
  11. Using a test light connected to battery voltage, probe EGR control circuit. If test light illuminates, go to step  15. If test light does not illuminate, go to step  16.
  12. Replace and reprogram PCM using required equipment. See PROGRAMMING . Go to step  19.
  13. Check EGR ground circuit for poor connection at PCM harness connector. Repair as necessary. Go to step  19. If connection is okay, go to step  17.
  14. Check EGR 5-volt reference circuit for a short to voltage. Repair as necessary. Go to step  19. If short to voltage does not exist, go back to step  12.
  15. Check EGR control circuit for a short to ground. Repair as necessary. Go to step  19. If short does not exist, go back to step  12.
  16. Check EGR control circuit for an open or poor connection at EGR valve harness connector. Repair as necessary. Go to step  19. If an open or poor connection does not exist, go to step  18.
  17. Replace EGR valve. Go to step  19.
  18. Check PCM harness connectors for poor connection. Repair as necessary. Go to next step. If no problem was found, go back to step  12.
  19. Using scan tool, clear DTCs. Start engine and idle to normal operating temperature. Operate vehicle within conditions for setting DTC P0404. See CIRCUIT DESCRIPTION. If scan tool indicates diagnostic RAN AND PASSED, system is okay. If scan tool indicates diagnostic did not pass, go to step  2.
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