Circuit/System Testing

Leak Testing

IMPORTANT:
• You must start with the Circuit/System Verification before proceeding with Circuit/System Testing.
• 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. 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 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, if equipped. Or, disconnect the EVAP purge pipe from the purge solenoid. Once smoke is observed, remove the tool, or reconnect the EVAP purge pipe.
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.
7. Verify the EVAP system using the EVAP service port. Connect the J 41413-200  nitrogen/smoke supply hose to the EVAP service port. See Special Tools . Connect the CH-48096  EVAP Service Port Access Tool between the EVAP purge solenoid and the EVAP purge pipe, if necessary. See Special Tools .
8. Command the EVAP vent solenoid closed with a scan tool.
9. Use the remote switch to introduce smoke into the EVAP system.
IMPORTANT: The fuel tank may need to be lowered to improve visibility of some of the EVAP system components.
10. Verify that smoke is not exiting the entire EVAP system with the J 41413-SPT  . See Special Tools .
    • If smoke is observed, repair the condition as necessary.
IMPORTANT: The fuel tank may need to be lowered to improve visibility of some of the EVAP system components.
11. Verify the individual EVAP system components for a leak using the J 41413-300  . See Special Tools .
    • If a condition is found replace the affected component.

Blockage/Restriction Testing

1. Connect the GE-41415-50  to the fuel tank filler neck. Connect the J 41413-200  to the GE-41415-50  . See Special Tools .
2. Seal the EVAP system using the EVAP Purge/Seal function with a scan tool.
3. Pressurize the EVAP system with nitrogen to 5 inches H2O. Compare the Fuel Tank Pressure Sensor parameter to the J 41413-200  pressure/vacuum gage. See Special Tools . The FTP sensor parameter should be within 1 inch H2O of the pressure/vacuum gage.
   • If the FTP sensor parameter is not within 1 inch H2O 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.