Abstract: An electronic control system for controlling an automatic transmission determines a gear position based on vehicle speed data immediately before a power supply is cut off. The gear position is determined during a transient period occurring after the electronic control system is reset by the power supply cutoff, until the control system resumes stable operation. Even when the electronic control system is reset by the instantaneous power supply cutoff while the vehicle is travelling, the electronic control system allows the vehicle to run safely without erroneous gear shifting immediately afterwards.

Abstract: A clutch target position control system of an engine includes a clutch actuator for controlling a clutch stroke, a sensor for detecting a parameter corresponding to an accelerator pedal depression amount, an engine revolution sensor for detecting a revolution speed of the engine and an input shaft revolution sensor for detecting a revolution speed of the input shaft. The disclosed system utilizes the steps of: reading clutch engagement amounts from map tables of registered data corresponding to each of the sensors, the detected signals from each sensor being converted into and used as address signals; calculating a total of three read clutch engagement amounts; and controlling the clutch actuator to control the actual clutch engagement amount on the basis of the calculated total amount.

Abstract: An electronic control system for controlling an automatic transmission mounted on a vehicle determines whether a vehicle speed sensor is abnormal or not when the transmission gears are in a neutral gear position. If the vehicle speed sensor is abnormal, then vehicle speed data immediately before the vehicle speed sensor becomes abnormal is stored, and a gear position is determined based on the stored vehicle speed data for a predetermined period of time after the transmission gears are shifted from the neutral gear position to another gear position.

Abstract: The number of steps required for a step motor to reach a target load is computed by dividing in proportion the number of steps required for the step motor to move a fuel metering member to move from an idle position to a full-load position by a ratio between a target load value of an electric command given by fuel supply command means such as an accelerator pedal to an internal combustion engine and a maximum value of the electric command. The step motor is driven by the computed step number to correct variations in the characteristics of the fuel supply command means. The number of load estimation steps for the step motor driven by drive means is determined by dividing in proportion an electric maximum command given from the fuel supply control means by a ratio between the actual amount of rotation of the step motor and the amount of rotation from the idle position to the full-load position, and a step-out condition of the step motor is detected from the estimation step number.