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Diagnostic Procedures

WARNING: This page is about a different car, the 2002 Oldsmobile Intrigue and 2002 Oldsmobile Aurora. However, it is still accessible from the selected car via links, so may be relevant.
  1. Did you perform the Diagnostic System Check - Engine Controls? If yes, go to next step. If no, go to DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS  under SELF-DIAGNOSTIC SYSTEM.
    NOTE: If DTC P0403 is set, diagnose DTC before continuing with this test. See DTC P0403: EGR SOLENOID CONTROL CIRCUIT .
  2. Ensure ignition is on. Using scan tool, check EGR position sensor parameter. If scan tool indicates zero percent, go to next step. If scan tool does not indicate zero percent, go to step  5.
  3. Using scan tool, command EGR valve from zero percent to 100 percent. If desired EGR position remains close to EGR position sensor at all commanded positions, go to next step. If desired EGR position does not remain close to EGR position sensor at all commanded positions, go to step  6.
  4. Using scan tool, observe and record FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC or as close to recorded FREEZE FRAME/FAILURE RECORDS data as possible. If DTC resets, go to next step. If DTC does not reset, see DIAGNOSTIC AIDS .
  5. Disconnect EGR valve connector. Turn ignition on. Using scan tool, observe EGR position sensor parameter. If scan tool indicates zero percent, go to next step. If scan tool does not indicate zero percent, go to step  9.
  6. Measure the voltage from the 5-volt reference circuit of EGR position sensor to the low reference circuit of EGR position sensor. Does the Digital Multimeter (DMM) display voltage about 5 volts? If yes, go to next step. If no, go to step  8.
    7. NOTE: If fuse blows, locate and repair a short to ground in the signal circuit.
  7. Connect a fused jumper between the 5-volt reference circuit of the EGR position sensor and EGR valve position signal circuit of EGR position sensor. Does scan tool indicate that the EGR position sensor value is about 100 percent? If yes, go to step  13. If no, go to step  11.
  8. Measure the voltage from the 5-volt reference circuit of the EGR position sensor to a good ground. Does DMM display voltage about 5 volts? If yes, go to step  10. If no, go to step  12.
  9. Test the EGR valve position signal circuit for a short to voltage. Did you find and correct the condition? If yes, go to step  17. If no, go to step  14.
  10. Test the EGR position sensor low reference circuit for an open or high resistance. Did you find and correct the condition? If yes, go to step  17. If no, go to step  14.
  11. Test the signal circuit for high resistance or a high resistance short to ground. Did you find and correct the condition? If yes, go to step  17. If no, go to step  15.
  12. 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  17. If no, go to step  15
  13. Check for poor connections at EGR valve connector. Repair connector as necessary. After repairs, go to step  17. If connector is okay, go to step  16.
  14. Check for poor connections at PCM connectors. Repair connectors as necessary. After repairs, go to step  17. If connectors are okay, go to step  16.
  15. Replace EGR valve. After repairs, go to step  17.
  16. Replace PCM. Program replacement PCM. See PROGRAMMING . After repairs, go to next step.
  17. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC. If DTC runs and passes, go to next step. If DTC resets, go to step  2.
  18. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, system is okay. If any other DTCs are set, repair DTCs as necessary. See DIAGNOSTIC TROUBLE CODE DEFINITIONS .
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