Some 2017-2018 Energi and Hybrid vehicles may exhibit a fuel door opening delay longer than 15 sec or unable to open condition without refueling system or fuel door related DTCs. This condition may be due to the high pressure fuel tank pressure transducer (HPFTPT) functionality. Check the HPFTPT after opening the fuel door by releasing the mechanical lever located in the trunk. Install supplemental refueling adaptor in the vehicle to open the capless fuel tank filler pipe. During key on engine off (KOEO) condition check if the fuel tank pressure transducer (FTPT) voltage is between 1.4 1.54 V at atmospheric pressure in the tank. If the voltage is within the range, FTPT is functioning as intended. Check the fuel vapor vent valve (FVVV), also called refueling valve, integrity by following Workshop Manual (WSM), Section 310-00.
