Methods and systems are provided for indicating a restriction in a fuel system vapor recovery line. Responsive to such an indication, methods and systems are provided for taking mitigating actions such that an entirety of a vehicle fuel system and evaporative emissions system, including a fuel filler system, may be diagnosed as to a presence or absence of undesired evaporative emissions, even with the restriction in the vapor recovery line present. In this way, undesired evaporative emissions may be reduced or avoided, completion rates for such tests may be increased, and customer satisfaction may be improved.

Methods and systems are provided for a fuel system. In one example, a method may include cleaning an orifice of an ELCM. The cleaning includes adjusting a position of a valve in a passage to fluidly couple a reference orifice of the ELCM to an intake manifold.

A leak hole determination device in an evaporated fuel processing system. The leak hole determination device includes: a first pressure detector for detecting a first pressure in a fuel tank; a second pressure detector for detecting a second pressure in a canister; and a leak hole determiner for determining whether a leak hole is present. The leak hole determiner determines, after a limit pressure timing subsequent to a depressurization operation for depressurizing an inside of the system, whether a leak hole is present by using a difference between a change speed of a first pressure detected by the first pressure detector and a change speed of a second pressure detected by the second pressure detector.

Methods and systems are provided for a diagnostic of a pressure sensor. In one example, a method includes bypassing one or more vapor canisters and determining a condition of the pressure sensor based on feedback from a hydrocarbon sensor.

A vaporized fuel treating device having a canister that is configured to adsorb vaporized fuel in a fuel tank and to feed the adsorbed vaporized fuel to an engine may include a pressure sensor that is configured to periodically detect an inner pressure of the fuel tank, and a pressure sensor failure determination device that is configured to determine that the pressure sensor has failed when a change of the inner pressure detected by the pressure sensor in a unit of time is not less than a predetermined pressure value that is greater than a maximum value of possible pressure changes within the fuel tank.

A method for a fuel system, comprising: indicating a leak in a fuel tank following applying a vacuum to the fuel tank by running a vacuum pump in a first direction; then purging a fuel vapor canister to the fuel tank by running the vacuum pump in a second direction, opposite the first direction. In this way, the fuel vapor canister may be purged of its contents following a fuel system leak check. This may reduce bleed emissions while increasing the efficiency of the vehicle, as the engine does not need to be turned on in order to purge the canister.

Methods and systems for diagnosing operational status of a carbon filled canister heater are described. The methods and systems may include activating an evaporative emissions system heater, a pump, and a canister purge valve to determine if long chain hydrocarbons are released from a carbon filled canister. Release of long chain hydrocarbons from the carbon filled canister may be indicative of desired operation of a carbon filled canister heater.

A method for diagnosing fuel leakage of a vehicle includes: measuring a pressure of a fuel tank by a pressure sensor in a closed state of a fuel system during starting-off of the vehicle; measuring an inner temperature of the fuel tank by a temperature sensor; and diagnosing, by a controller, whether or not leakage occurs by performing different leakage diagnoses depending on a pressure condition of the fuel tank. Thus, the controller performs a first leakage diagnosis when a pressure value of the fuel tank, measured in the measuring the pressure of the fuel tank, is within an atmospheric pressure level; performs a second leakage diagnosis when the pressure value is higher than a positive pressure; and performs a third leakage diagnosis when the pressure value is lower than a negative pressure.

A fuel tank venting system for a motor vehicle includes an outlet side of a tank venting valve connected to an inlet side of a first vent line and to an inlet side of a second vent line. An outlet side of the first vent line is connected to an intake manifold upstream from a throttle valve and downstream from an air filter, and an outlet side of the second vent line is connected to the intake manifold downstream from the throttle valve. A position sensor may be located at a first position and the first closing element has a detectable element. The position sensor is connected to an electronic control device to transmit signals. A position of the first closing element may be determined by means of the position sensor and the detectable element.

A method for operating a vehicle system is provided. The method includes monitoring a change in a temperature of the fuel vapor canister coupled to a fuel tank via a canister temperature sensor and adjusting operation of a fuel tank isolation valve based on the change in temperature of the fuel vapor canister.