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Diagnostic Procedures

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  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. Install a scan tool. Turn ON the ignition, with the engine OFF. With a scan tool, command the EGR valve from 0-100 percent. Does the EGR position sensor remain close to the desired EGR position at all commanded positions? If yes, go to next step. If no, go to step  4.
  3. Observe the Freeze Frame/Failure Records data for this DTC. Turn OFF the ignition for 30 seconds. Operate the vehicle within the Conditions for Running DTC or as close to the Freeze Frame/Failure Records data that you observed. Does the DTC fail this ignition? If yes, go to next step. If no, see DIAGNOSTIC AIDS .
  4. With a scan tool, observe the EGR position sensor parameter. Does the scan tool indicate that the EGR position sensor is at 0 percent? If yes, go to step  7. If no, go to next step.
  5. Turn OFF the ignition. Disconnect the EGR valve connector. Turn ON the ignition, with the engine OFF. With a scan tool, observe the EGR position sensor parameter. Does the scan tool indicate that the EGR position sensor is at 0 percent? If yes, go to next step. If no, go to step  16.
  6. Turn ON the ignition, with the engine OFF. Probe the EGR solenoid high control circuit with a test lamp connected to a good ground. With a scan tool, command the EGR valve between 0-10 percent. Does the test lamp turn ON and OFF with each command? If yes, go to step  10. If no, go to step  9.
  7. Turn OFF the ignition. Disconnect the EGR valve connector. Turn ON the ignition, with the engine OFF. Probe the EGR solenoid high control circuit with a test lamp connected to a good ground. With a scan tool, command the EGR between 0-10 percent. Does the test lamp turn ON and OFF with each command? If yes, go to next step. If no, go to step  9.
  8. Connect a test lamp between the EGR solenoid high control circuit and the EGR solenoid low control circuit. With a scan tool, command the EGR valve between 0-10 percent. Does the test lamp turn ON and OFF with each command? If yes, go to step  20. If no, go to step  15.
  9. Does the test lamp remain illuminated with each command? If yes, go to step  14. If no, go to step  13.
  10. Measure the voltage from the 5-volt reference circuit of the EGR position sensor to the low reference circuit of the EGR position sensor. Does the Digital Multimeter (DMM) display voltage near 5.0 V? If yes, go to next step. If no, go to step  12.
    11. NOTE: If the fuse opens, locate and repair a short to ground in the signal circuit.
  11. Connect a fused jumper between the 5-volt reference circuit of the EGR position sensor and the EGR valve position signal circuit of the EGR position sensor. Does the scan tool indicate that the EGR position sensor is near 100 percent? If yes, go to step  20. If no, go to step  18.
  12. Measure the voltage from the 5-volt reference circuit of the EGR position sensor to a good ground. Does the DMM display voltage near 5.0 V? If yes, go to step  17. If no, go to step  19.
  13. Test the EGR solenoid high control circuit for a short to ground, high resistance or an open. Did you find and correct the condition? If yes, go to step  24. If no, go to step  21.
  14. Test the EGR solenoid high control circuit for a short to voltage. Did you find and correct the condition? If yes, go to step  24. If no, go to step  21.
  15. Test the EGR solenoid low control circuit for an open or high resistance. Did you find and correct the condition? If yes, go to step  24. If no, go to step  21.
  16. Test the EGR valve position signal circuit for a short to voltage. Did you find and correct the condition? If yes, go to step  24. If no, go to step  21.
  17. Test the low reference circuit for an open or high resistance. Did you find and correct the condition? If yes, go to step  24. If no, go to step  21.
  18. Test the EGR valve position signal circuit for high resistance or a high resistance short to ground. Did you find and correct the condition? If yes, go to step  24. If no, go to step  21.
  19. Test the 5-volt reference circuit of the EGR position sensor for an open, a short to ground, or a short to voltage. Did you find and correct the condition? If yes, go to step  24. If no, go to step  21.
  20. Inspect for poor connections at the harness connector of the EGR valve. Did you find and correct the condition? If yes, go to step  24. If no, go to step  22.
  21. Inspect for poor connections at the harness connector of the PCM. Did you find and correct the condition? If yes, go to step  24. If no, go to step  23.
  22. Replace the EGR valve. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step  24.
  23. Replace the PCM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram PCM. See POWERTRAIN CONTROL MODULE  under PROGRAMMING. After repairs, go to next step.
  24. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step  2.
  25. 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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