Abstract: A method of diagnosing failure of fuel level sensors includes a first measuring step of measuring voltages from first and second failure detection terminals; if the voltage is higher than a reference, diagnosing the voltage as “high,” and if the voltage is lower than a reference, diagnosing the voltage as “low;” and if the voltage is neither high nor low: a second measuring step of receiving the voltages from the first and second failure detection terminals; calculating and storing a difference between the voltages of the first and second failure detection terminals; determining whether an amount of fuel is reduced; if the amount of fuel is reduced, calculating a difference between voltage signals of the first and second failure detection terminals; determining whether the voltage difference before and after the amount of fuel was reduced are identical; and if the voltage differences are identical, returning to the first measuring step.

Abstract: A method of diagnosing failure of fuel level sensors includes a first measuring step of measuring voltages from first and second failure detection terminals; if the voltage is higher than a reference, diagnosing the voltage as “high,” and if the voltage is lower than a reference, diagnosing the voltage as “low;” and if the voltage is neither high nor low: a second measuring step of receiving the voltages from the first and second failure detection terminals; calculating and storing a difference between the voltages of the first and second failure detection terminals; determining whether an amount of fuel is reduced; if the amount of fuel is reduced, calculating a difference between voltage signals of the first and second failure detection terminals; determining whether the voltage difference before and after the amount of fuel was reduced are identical; and if the voltage differences are identical, returning to the first measuring step.

Abstract: A method and system for diagnosing a failure of a rear oxygen sensor is provided. The sensor is determined to have failed if the difference between a maximum output value and a minimum value of the rear oxygen sensor is less than a first value, and if it is not, it is determined whether the difference is between the first value and a second value. If so, the air/fuel mixture is controlled to be richer than a stoichiometric air/fuel ratio for a predetermined period. Then, an output values of a front oxygen sensor and the rear oxygen sensor are respectively compared to first and second threshold values. If the output value of the front oxygen sensor is greater than the first threshold value, and the output value of the rear oxygen sensor is less than the second threshold value, it is determined that the rear oxygen sensor has failed.

Abstract: A method and system for controlling a limp-home function in an electronic throttle system adapted to prevent stalls which may occur due to failure of electronic throttle system by executing proper limp-home control to cater to a running state of the vehicle.

Abstract: A method and system for diagnosing a failure of a rear oxygen sensor is provided. The sensor is determined to have failed if the difference between a maximum output value and a minimum value of the rear oxygen sensor is less than a first value, and if it is not, it is determined whether the difference is between the first value and a second value. If so, the air/fuel mixture is controlled to be richer than a stoichiometric air/fuel ratio for a predetermined period. Then, an output values of a front oxygen sensor and the rear oxygen sensor are respectively compared to first and second threshold values. If the output value of the front oxygen sensor is greater than the first threshold value, and the output value of the rear oxygen sensor is less than the second threshold value, it is determined that the rear oxygen sensor has failed.

Abstract: A method and system for controlling a limp-home function in an electronic throttle system adapted to prevent stalls which may occur due to failure of electronic throttle system by executing proper limp-home control to cater to a running state of the vehicle.