Methods and systems are provided for conducting a fuel tank pressure transducer rationality test diagnostic procedure in vehicles with sealed fuel tanks. In one example, vehicle-to-vehicle (V2V) or vehicle-to-infrastructure-to-vehicle (V2I2V) technology may be utilized to obtain fuel tank pressure transducer data from a select crowd of vehicles, where the select crowd may be based on the vehicles in the select crowd experiencing similar ambient temperature and weather as the vehicle being diagnosed. In this way, FTPT data from vehicles in the select crowd may be compared to FTPT data in the vehicle being diagnosed, in order to indicate whether the FTPT in the vehicle being diagnosed is functioning as desired, where such a diagnostic can be performed without unsealing the fuel tank on either the vehicle being diagnosed or the vehicles in the select crowd, and which may thus reduce undesired evaporative emissions.

An abnormality determination device includes an injection instructor that realizes a rich state of an air-fuel ratio in an exhaust gas by sending an instruction of (i) stopping an application of bias to a plus terminal and (ii) adjusting a fuel injection amount from an injector, and an abnormality determiner that distinctively determines abnormality of, i.e., in terms of which one of, the plus terminal or a minus terminal having a sky failure or a ground failure by detecting an electromotive force of an air-fuel ratio sensor when the air-fuel ratio in the exhaust gas is in the rich state according to the instruction of the injection instructor.

Methods and systems are provided for an engine including a humidity sensor. Degradation of the humidity sensor may be determined based on a change in intake air relative humidity as compared to a change in intake air temperature or pressure, under selected conditions. An amount of exhaust gas recirculated to an engine intake is adjusted differently based on whether the humidity sensor is degraded or functional.

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 method is provided for determining the fuel temperature in the high-pressure zone of a fuel injection system of a motor vehicle. The fuel injection system has at least one injector operated by a servo valve which is actuated by means of a piezo actuator. After an injection process has been carried out, the piezo actuator is discharged after the injection has ended in such a way that the servo valve can close, but a non-positive connection remains between the piezo actuator and the servo valve. This condition of reduced charge is maintained. The pressure oscillation of the actuator voltage resulting from this is recorded and from this the hydraulic natural frequency of the enclosed high-pressure volume of fuel is deduced. The prevailing fuel temperature can be determined from the natural frequency.

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.

An engine ECU is provided with an abnormality-diagnosis unit performing an abnormality diagnosis of an Air-Con ECU, and a monitoring IC monitoring the abnormality-diagnosis unit. The abnormality-diagnosis unit determines whether the output signal of the Air-Con ECU is normal based on the specified criterion value, so that the abnormality diagnosis of the Air-Con ECU is performed. The monitoring IC determines whether a criterion value is normal, which is used during the abnormality diagnosis of the Air-Con ECU. The abnormality-diagnosis unit performs an abnormality diagnosis of the monitoring IC. When the monitoring IC determines that the criterion value is abnormal or the abnormality-diagnosis unit determines that the monitoring IC is abnormal, the abnormality diagnosis of the Air-Con ECU is prohibited and a specified operation for abnormality is performed.

An abnormality diagnosis device includes a partially-plugged filter, a pressure difference sensor, a PM sensor, a first estimation portion estimating a diagnosis amount of PM from the partially-plugged filter, according to a running condition of the internal combustion engine, a second estimation portion estimating the diagnosis amount of PM according to an output of the pressure difference sensor, a third estimation portion estimating the diagnosis amount of PM according to an output of the PM sensor, and an abnormality diagnosis portion distinctly determining an abnormality of the internal combustion engine, an abnormality of the partially-plugged filter, and an abnormality of the PM sensor by comparing the diagnosis amount of PM estimated by the first estimation portion, the diagnosis amount of PM estimated by the second estimation portion, and the diagnosis amount of PM estimated by the third estimation portion.

A method is for route identification that is conducive for successful diagnosis of an exhaust gas treatment system of a vehicle. In the method, an ECU in the vehicle receives a value of GPS coordinates from a GPS module, and the ECU retrieves a value of day, date, and time from an ECU clock. The ECU monitors a value of engine operating conditions with reference to the received value of GPS coordinates and the retrieved value of day, date, and time. The ECU identifies a segment of GPS coordinates for successful diagnosis of an exhaust gas treatment system based on the monitored value. Upon the identification, the segment of GPS coordinates is stored in ECU memory.

Methods and systems for calculating a plurality of aging factors in a system operating an engine. The calculated aging factors may include one or more of fuel injector drift, exhaust gas recirculation valve obstruction, and mass air flow sensor bias. Mass flow throughout the system, and pressures and temperatures within the system, are observed in an approach that relies on mass preservation concepts to estimate fuel injector drift, exhaust gas recirculation valve obstruction, and mass air flow sensor bias.