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Diagnostic Procedures

WARNING: This page is about a different car, the 2003 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.
  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. Inspect the EVAP system for a loose, missing, or damaged service port Schrader valve. Check for a loose, incorrect, missing, or damaged fuel fill cap. Check for damaged EVAP purge solenoid. Raise vehicle on a hoist and inspect the EVAP system for any disconnected, improperly routed, kinked, damaged EVAP pipes and hoses. Check for damaged EVAP vent solenoid, or EVAP canister. Did you find and correct the condition? If yes, go to step  34. If no, go to next step.
  3. Clear the DTCs with a scan tool. Command the EVAP purge solenoid to 50 percent and back to zero percent with a scan tool. Do you hear or feel a clicking from the EVAP purge solenoid when it is commanded to 50 percent? If yes, go to next step. If no, go to step  5.
  4. Command the EVAP vent solenoid ON and OFF with the scan tool. Do you hear or feel a click as the EVAP vent solenoid is commanded ON and OFF? If yes, go to step  9. If no, go to step  7.
  5. Disconnect the EVAP purge solenoid. Turn ignition on, with engine off. Connect a test light between the ignition 1 voltage circuit of the EVAP purge solenoid and a known-good ground. Does the test light illuminate? If yes, go to next step. If no, go to step  25.
  6. Connect a test light between the ignition 1 voltage circuit of the EVAP purge solenoid and the control circuit of the EVAP purge solenoid. Command the EVAP purge solenoid to 50 percent and then to zero percent with a scan tool. Does the test light illuminate or pulsate when the EVAP purge solenoid is commanded to 50 percent and turn off when the EVAP purge solenoid is commanded to zero percent? If yes, go to step  20. If no, go to step  18.
  7. Turn ignition on, with engine off. Disconnect the EVAP vent solenoid. Connect a test light between the ignition 1 voltage circuit of the EVAP vent solenoid and a known-good ground. Does the test light illuminate? If yes, go to next step. If no, go to step  26.
  8. Connect a test light between the ignition 1 voltage circuit of the EVAP vent solenoid and the control circuit of the EVAP vent solenoid. Command the EVAP vent solenoid on with a scan tool. Does the test light illuminate? If yes, go to step  21. If no, go to step  19.
    9. NOTE: Ensure that vehicle underbody temperature is similar to the ambient temperature and allow the surrounding air to stabilize before starting the diagnostic procedure. System flow will be less with higher temperatures.
  9. Turn ignition off. Connect the OBD II/Enhanced Emissions Testing Equipment (J-41750) power supply clips to a known-good 12-volt source. Install the Fuel Tank Cap Adapter (J-41415-40) to the fuel fill pipe. Connect the fuel fill cap to the fuel tank cap adapter. Connect the J-41750 nitrogen/smoke supply hose to the J-41415-40. Turn ignition on, with engine off. Command the EVAP vent solenoid closed with a scan tool. Turn the nitrogen/smoke valve on the J-41750 control panel to SMOKE. Use the remote switch to introduce smoke into the EVAP system. Use the EVAP Service Port Vent Fitting (J-41413-VLV) to open the EVAP service port. Remove the J-41413-VLV once smoke is observed. Continue to introduce smoke into the EVAP system for an additional 60 seconds. Inspect the entire EVAP system for exiting smoke with the High Intensity White Light (J-41413-SPT). Continue to introduce smoke at 15 second intervals until the leak source has been located. Did you locate and repair a leak source? If yes, go to step  34. If no, go to next step.
  10. Disconnect the J-41415-40 from the fuel fill pipe. Install the fuel fill cap to the fuel fill pipe. Connect the J-41750 nitrogen/smoke supply hose to the EVAP service port. Use the remote switch to introduce smoke into the EVAP system. Inspect the entire EVAP system for exiting smoke with the J-41413-SPT. Continue to introduce smoke at 15 second intervals until the leak source has been located. Did you locate and repair a leak source? If yes, go to step  34. If no, go to next step.
  11. Use the remote switch to stop introducing smoke. Install the J-41415-40 to the fuel fill pipe. Connect the J-41750 nitrogen/smoke supply hose to the J-41415-40. Connect the vehicle fuel fill cap to the J-41415-40. Command the EVAP vent solenoid open with a scan tool. Compare the Fuel Tank Pressure Sensor parameter with a scan tool, to the Pressure/Vacuum Gauge (J-41750). Is the scan tool Fuel Tank Pressure Sensor parameter within 1.30-1.70 volts? If yes, go to next step. If no, go to step  22.
  12. Seal the EVAP system using the EVAP Purge/Seal function with a scan tool. Turn the nitrogen/smoke valve on the J-41750 control panel to NITROGEN. Use the J-41750 to pressurize the EVAP system to 10 in. H2O on the pressure/vacuum gauge. Is the Fuel Tank Pressure Sensor parameter less than 0.5 volt? If yes, go to next step. If no, go to step  22.
  13. Use the remote switch to stop introducing nitrogen into the EVAP system. Increase the EVAP purge solenoid to 100 percent. Is the Fuel Tank Pressure Sensor parameter 1.30-1.70 volts? If yes, go to DIAGNOSTIC AIDS . If no, go to next step.
  14. Disconnect the EVAP purge vacuum source from the EVAP purge solenoid. Is the Fuel Tank Pressure Sensor parameter 1.30-1.70 volts? If yes, go to step  24. If no, go to next step.
  15. Disconnect the EVAP purge pipe from the EVAP purge solenoid. Is the Fuel Tank Pressure Sensor parameter 1.30-1.70 volts? If yes, go to step  29. If no, go to next step.
  16. Disconnect the EVAP purge pipe at the EVAP canister. Is the Fuel Tank Pressure Sensor parameter 1.30-1.70 volts? If yes, go to step  27. If no, go to next step.
  17. Disconnect the EVAP vapor pipe at the EVAP canister. Is the Fuel Tank Pressure Sensor parameter 1.30-1.70 volts? If yes, go to step  31. If no, go to step  28.
  18. Test control circuit of the EVAP purge solenoid for an open or for a short to voltage. Did you find and correct the condition? If yes, go to step  34. If no, go to step  23.
  19. Test control circuit of the EVAP vent solenoid for an open or for a short to voltage. Did you find and correct the condition? If yes, go to step  34. If no, go to step  23.
  20. Test for an intermittent and for a poor connection at the EVAP canister purge solenoid. Did you find and correct the condition? If yes, go to step  34. If no, go to step  29.
  21. Test for an intermittent and for a poor connection at the EVAP vent solenoid. Did you find and correct the condition? If yes, go to step  34. If no, go to step  30.
  22. Test for an intermittent and for a poor connection at the Fuel Tank Pressure (FTP) sensor. Did you find and correct the condition? If yes, go to step  34. If no, go to step  32.
  23. Test for an intermittent and for a poor connection at the control module. Did you find and correct the condition? If yes, go to step  34. If no, go to step  33.
  24. Repair the pinched or obstructed EVAP purge solenoid vacuum source. After repairs, go to step  34.
  25. Repair the open or short to ground in the ignition 1 voltage circuit of the EVAP purge solenoid. Replace the fuse as necessary. After repairs, go to step  34.
  26. Repair the open or short to ground in the ignition 1 voltage circuit of the EVAP vent solenoid. Replace the fuse as necessary. After repairs, go to step  34.
  27. Repair the restriction in the EVAP purge pipe. After repairs, go to step  34.
  28. Repair restriction in the EVAP vapor pipe. After repairs, go to step  34.
  29. Replace EVAP purge solenoid. After replacing solenoid, go to step  34.
  30. Replace EVAP vent solenoid. After replacing solenoid, go to step  34.
  31. Replace EVAP canister. After replacing EVAP canister, go to step  34.
  32. Replace FTP sensor. After replacing sensor, go to step  34.
  33. Turn ignition off. Replace ECM. Perform ECM relearn procedure. See ELECTRONIC CONTROL MODULE REPROGRAMMING  under PROGRAMMING. After replacing ECM, go to next step.
    34. NOTE: Larger volume fuel tanks and/or those with lower fuel levels may require several minutes for the floating indicator to stabilize.
  34. Turn the nitrogen/smoke valve to NITROGEN. Connect the nitrogen/smoke hose to the 0.20" (0.5 mm) test orifice on the bottom front of the J-41413-200. Use the remote switch to activate the J-41413-200. Align the Red flag on the flow meter with the floating indicator. Use the remote switch to de-activate the J-41413-200. Install the J-41415-40 to the fuel fill pipe. Remove the nitrogen/smoke hose from the test orifice and install the hose onto the J-41415-40. Turn ignition on, with engine off. Command the EVAP vent solenoid closed with a scan tool. Use the remote switch to introduce nitrogen and fill the EVAP system until the floating stabilizes. Compare the flow meters stable floating indicator position to the Red flag. Is the floating indicator below the Red flag? If yes, go to next step. If no, go to step  2.
  35. With a scan tool, observe the stored information, Capture Info. 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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