Blockage/Restriction Testing

Connect the GE-41415-50 to the fuel tank filler neck. Connect the J 41413-200 to the GE-41415-50 . See Special Tools .
Seal the EVAP system using the EVAP Purge/Seal function with a scan tool.
Pressurize the EVAP system with nitrogen to 5 inches H20. 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 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.
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 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
If you cannot locate a condition with the EVAP system, refer to Diagnostic Aids for additional information.