Circuit/System Testing

Leak Testing

IMPORTANT: Ensure that the vehicle underbody temperature is similar to the ambient temperature and allow the surrounding air to stabilize before starting the diagnostic procedure. The system flow will be less with higher temperatures.
1. Connect the GE-41415-50  to the fuel tank filler neck. See Special Tools . Connect the J 41413-200  to the GE-41415-50  . See Special Tools .
2. Turn the nitrogen/smoke valve on the control panel to SMOKE.
3. Command the evaporative emission (EVAP) vent solenoid closed with a scan tool.
4. Use the remote switch to introduce smoke into the EVAP system.
5. Use the J 41413-VLV  to open the EVAP service port. See Special Tools . Once smoke is observed, remove the tool.
IMPORTANT: Introduce smoke at 15 second intervals while testing the system.
6. Verify that smoke is not exiting the entire EVAP system with the J 41413-SPT  . See Special Tools .
   IMPORTANT: The fuel tank may need to be lowered to improve visibility of some of the EVAP system components.
   • If smoke is observed, repair the condition as necessary.
   • If smoke is not observed, verify the EVAP system using the EVAP service port.
7. Connect the J 41413-200  nitrogen/smoke supply hose to the EVAP service port. See Special Tools .
8. Command the evaporative emission (EVAP) vent solenoid closed with a scan tool.
9. Use the remote switch to introduce smoke into the EVAP system.
10. Verify that smoke is not exiting the entire EVAP system with the J 41413-SPT  . See Special Tools .
    IMPORTANT: The fuel tank may need to be lowered to improve visibility of some of the EVAP system components.
    • If smoke is observed, repair the condition as necessary.
    • If smoke is not observed, test the individual EVAP system components for a leak using the J 41413-300  . See Special Tools .

Blockage/Restriction Testing

1. Connect the GE-41415-50  to the fuel tank filler neck. See Special Tools . Connect the J 41413-200  to the GE-41415-50  . See Special Tools .
2. Disconnect the EVAP vent line from the vent solenoid, and seal it, using the correct plug from the J 41413-300  . See Special Tools .
3. Pressurize the EVAP system with nitrogen to 10 inches H20. Compare the Fuel Tank Pressure Sensor parameter with a scan tool to the J 41413-200  pressure/vacuum gage. See Special Tools . The scan tool FTP sensor parameter should be within 1 inch H20 of the pressure/vacuum gage.
   • If the FTP sensor parameter is not within 1 inch H20 of the pressure/vacuum gage, replace the FTP sensor.
4. Increase the EVAP purge solenoid to 100 percent. The FTP sensor pressure should drop to less than 1 in H2O.
   • If the FTP sensor parameter is greater than 1 in H2O, disconnect the EVAP pipes listed below one at a time while observing the FTP sensor parameter with a scan tool. If the FTP sensor parameter drops to less than 1 in H2O when a pipe is disconnected, repair the blockage or restriction in the one of the following EVAP pipe/hoses:
     1. EVAP purge vacuum source from the EVAP purge solenoid
     2. EVAP purge pipe from the EVAP purge solenoid
     3. EVAP purge pipe at the EVAP canister
     4. EVAP vapor pipe at the EVAP canister
5. If you cannot locate a condition with the EVAP system, refer to Diagnostic Aids for additional information.