Circuit/System Testing
- Ignition OFF, remove the fuel tank filler cap.
- Ignition ON, observe the scan tool fuel tank pressure sensor voltage parameter. Verify the FTP sensor voltage parameter is less than 4 volts.
- Start the engine. With a scan tool seal the EVAP system using the EVAP purge seal function. Command the purge open to 20 percent. Seal the system at -8.00 inches H2O. Exit the system seal. Verify the FTP sensor pressure parameter decreases to 0 inches H2O.
- If the scan tool FTP sensor parameter does not decrease, check for a blockage or restrictions in the EVAP vent hose, or replace the EVAP vent solenoid valve.